U.S. patent application number 16/172562 was filed with the patent office on 2020-04-30 for methods of modifying the composition of material layers.
The applicant listed for this patent is TECTUS CORPORATION. Invention is credited to William Freeman, Hongjin Jiang.
Application Number | 20200135988 16/172562 |
Document ID | / |
Family ID | 70325523 |
Filed Date | 2020-04-30 |
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United States Patent
Application |
20200135988 |
Kind Code |
A1 |
Jiang; Hongjin ; et
al. |
April 30, 2020 |
METHODS OF MODIFYING THE COMPOSITION OF MATERIAL LAYERS
Abstract
Methods of modifying the composition of layers using selectively
absorbing films are described. The composition of a layer can be
modified by applying a selectively absorbing film in proximity to
the applied coating and components of the layer can be selectively
removed to provide a modified layers. The methods can be used to
increase the concentration of particles in the layer.
Inventors: |
Jiang; Hongjin; (Palo Alto,
CA) ; Freeman; William; (Palo Alto, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TECTUS CORPORATION |
SARATOGA |
CA |
US |
|
|
Family ID: |
70325523 |
Appl. No.: |
16/172562 |
Filed: |
October 26, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 27/156 20130101;
H01L 33/508 20130101; H01L 2933/0041 20130101 |
International
Class: |
H01L 33/50 20060101
H01L033/50; H01L 27/15 20060101 H01L027/15 |
Claims
1. A method of modifying the composition of a layer, comprising:
(a) applying a selectively absorbing film in proximity to a layer,
wherein the layer comprises a first composition, wherein the first
composition comprises particles and at least one additional
component; and (b) modifying the first composition by causing at
the at least one additional component to absorb into the
selectively absorbing film; to provide a modified layer, wherein
the modified layer comprises a second composition comprising
particles.
2. The method of claim 1, wherein modifying comprises concentrating
the particles, removing the at least one additional component from
the first composition, or a combination thereof.
3. The method of claim 1, wherein modifying comprises extracting
one or more low molecular weight components from the first
composition.
4. The method of claim 1, wherein modifying comprises decreasing a
volume of the layer.
5. The method of claim 1, wherein modifying comprises concentrating
the particles in the first composition.
6. The method of claim 1, wherein modifying comprises removing one
or more components from the first composition.
7. The method of claim 1, wherein the first composition comprises a
first vol % of the particles; the second composition comprises a
second vol % of the particles; and the second vol % is greater than
the first vol %.
8. The method of claim 1, wherein the particles comprise a
photoactive material.
9. The method of claim 1, wherein the particles comprise quantum
dots.
10. The method of claim 1, wherein the layer is disposed within one
or more recesses.
11. The method of claim 1, wherein the layer is disposed within one
or more recesses, wherein the recesses have a depth from 1 .mu.m to
4 .mu.m and a width from 1 .mu.m to 4 .mu.m.
12. The method of claim 1, wherein the first composition comprises:
a first concentration of a first component; and the second
composition comprises a second concentration of the first
component, wherein the second concentration is less than the first
concentration.
13. The method of claim 1, wherein a portion of the layer has a
first volume, and the portion of the modified layer corresponding
to the portion of the layer has a second volume, wherein the second
volume is less than the first volume.
14. The method of claim 1, wherein the first composition comprises
a first concentration of the particles; the modified layer
comprises a second concentration of the particles; wherein the
second concentration is greater than the first concentration.
15. A modified layer fabricated using the method of claim 1.
16. A cured modified layer prepared by curing the modified layer of
claim 15.
17. An electronic device comprising the cured modified layer of
claim 16.
18. A method of fabricating one or more pixels, comprising:
providing a substrate comprising one or more recesses, wherein each
of the one or more recesses defines a pixel; depositing a first
composition into each of the one or more recesses, wherein the
first composition comprises particles and one or more additional
components; applying a selectively absorbing film in proximity to
the deposited first composition; and causing one or more of the
additional components of the deposited first composition to absorb
into the selectively absorbing film, to provide one or more pixels
comprising a modified first composition.
19. The method of claim 18, wherein, the first composition
comprises a first vol % of the particles; and the modified first
composition comprises a second vol % of particles, wherein the
second vol % is greater than the first vol %, wherein vol % is
based on the volume of the first composition and the volume of the
modified composition, respectively
20. The method of claim 18, further comprising: depositing a second
composition onto the modified first composition, wherein the second
composition comprises particles and one or more additional
components; applying a selectively absorbing film in proximity to
the deposited second composition; and causing one or more of the
additional components of the deposited second composition to absorb
into the selectively absorbing film, to provide one or more pixels
comprising the modified first composition and a modified second
composition.
21. The method of claim 18, wherein the particles comprises a
photoactive material.
22. The method of claim 18, wherein the particles comprise quantum
dots.
23. A pixel fabricated using the method of claim 18.
24. The pixel of claim 23, wherein the particles comprise a
plurality of quantum dots.
25. An electronic device comprising the pixel of claim 23.
Description
FIELD
[0001] The disclosure relates to methods of modifying the
composition of layers and to modified layers using selectively
absorbing films. The composition of a layer can be modified by
applying a selectively absorbing film onto the layer and components
of the layer can be removed to modify the composition of the layer.
The methods can be used to increase the concentration of particles
in the layer.
BACKGROUND
[0002] Viscous pastes are widely used to manufacture electronic
devices. Pastes are used, for example, to deposit electrical
conductors and optoelectronic elements. The viscous pastes can be
applied using methods such as screen printing or roller coating. To
facilitate the application process, the viscosity of the paste can
be tailored to accommodate, for example, the dimensions of surface
features, feature pitch, feature aspect ratio, and application
speed. The viscosity can be adjusted, for example, using lower
molecular weight constituents, by adding solvents, rheological
control agents, and/or reactive diluents. Certain constituents can
react to form part of and/or become part of a cured polymer network
or binder. Other constituents are not bound to the polymeric
network and, with time, can leach or outgas from the cured
polymeric network. Furthermore, because these unbound constituents,
which are useful in the application process, can take up a
substantial volume percent of the paste, and can compromise device
performance. As a result, these constituents can limit the density
of particles that can be incorporated into a thin film.
[0003] It is desirable to have a method to modify the constituents
of a layer after the layer has been applied or deposited onto a
surface. Such methods can be used, for example, to remove
constituents included in the layer to facilitate application and/or
to remove constituents that may compromise device performance
during use.
SUMMARY
[0004] According to the present invention, methods of modifying the
composition of a layer comprise: (a) applying a selectively
absorbing film in proximity to a layer, wherein the layer comprises
a first composition, wherein the first composition comprises two or
more components; and (b) modifying the first composition by causing
at least one of the two or more components to absorb into the
selectively absorbing film, causing a component to absorb into the
first composition; or a combination thereof; to provide a modified
layer, wherein the modified layer comprises a second
composition.
[0005] According to the present invention, modified layers are
fabricated using methods according to the present invention.
[0006] According to the present invention, cured modified layers
are prepared by curing a modified layer according to the present
invention.
[0007] According to the present invention, electronic devices
comprise a cured modified layer according to the present
invention.
[0008] According to the present invention, electronic systems
comprise an electronic device according to the present
invention.
[0009] According to the present invention, selectively absorbing
films comprise one or more absorbing layers.
[0010] According to the present invention, methods of fabricating
one or more pixels comprise: providing a substrate comprising one
or more recesses, wherein each of the one or more recesses defines
a pixel; depositing a first composition into each of the one or
more recesses, wherein the first composition comprises one or more
components; applying a selectively absorbing film in proximity to
the deposited first composition; and causing one or more components
of the deposited first composition to absorb into the selectively
absorbing film, to provide one or more pixels comprising a modified
first composition.
[0011] According to the present invention, pixels are fabricated
using a method according to the present invention.
[0012] According to the present invention, electronic devices
comprise a pixel according to the present invention.
[0013] According to the present invention, electronic systems
comprise an electronic device according to the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The drawings described herein are for illustration purposes
only. The drawings are not intended to limit the scope of the
present disclosure.
[0015] FIGS. 1A-1C shows steps in the process of modifying a
deposited layer using a selectively absorbing film according to the
present invention.
[0016] FIG. 2A shows a multilayer selectively absorbing film
applied to a layer.
[0017] FIG. 2B shows a detailed view of an example of a multilayer
selectively absorbing film.
[0018] FIGS. 3A and 3B show cross-sectional views of a layer
deposited within wells.
[0019] FIGS. 4A and 4B show photographs of a display comprising a
plurality of 2 .mu.m-wide, 2 .mu.m-deep pixels fabricated using
methods provided by the present disclosure. FIG. 4A shows a
photograph of the display imaged with a 20.times. objective and
FIG. 4B shows a portion of the display imaged with a 50.times.
objective.
[0020] FIGS. 5A and 5B show photographs of another display
comprising a plurality of 10 .mu.m-wide, 2 .mu.m-deep pixels
fabricated using methods provided by the present disclosure. FIG.
5A shows a photograph of the display imaged with a 20.times.
objective and FIG. 5B shows a portion of the display imaged with a
50.times. objective.
[0021] FIGS. 6A-6F show steps for modifying the composition of a
layer using an absorbing film.
DETAILED DESCRIPTION
[0022] For purposes of the following detailed description, it is to
be understood that embodiments provided by the present disclosure
may assume various alternative variations and step sequences,
except where expressly specified to the contrary. Moreover, other
than in any operating examples, or where otherwise indicated, all
numbers expressing, for example, quantities of ingredients used in
the specification and claims are to be understood as being modified
in all instances by the term "about." Accordingly, unless indicated
to the contrary, the numerical parameters set forth in the
following specification and attached claims are approximations that
may vary depending upon the desired properties to be obtained by
the present invention. At the very least, and not as an attempt to
limit the application of the doctrine of equivalents to the scope
of the claims, each numerical parameter should at least be
construed in light of the number of reported significant digits and
by applying ordinary rounding techniques.
[0023] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the invention are approximations,
the numerical values set forth in the specific examples are
reported as precisely as possible. Any numerical value, however,
inherently contains certain errors necessarily resulting from the
standard variation found in their respective testing
measurements.
[0024] Also, it should be understood that any numerical range
recited herein is intended to include all sub-ranges subsumed
therein. For example, a range of "1 to 10" is intended to include
all sub-ranges between (and including) the recited minimum value of
1 and the recited maximum value of 10, that is, having a minimum
value equal to or greater than 1 and a maximum value of equal to or
less than 10.
[0025] The term "absorption" includes various chemical reactions
with the absorbing film such as ionic or covalent bonding that can
influence the mass action distribution in favor of certain of the
reactive mobile species migrating into the absorbing film.
Absorption can take place by active or passive mechanisms.
Absorption includes gradient-induced migration into or out of an
"absorbing" film. Absorption of a component can take place by one
or more mechanisms or processes. For example, a component can
migrate into the matrix of the absorbing film and covalently attach
to the matrix. As another example, a component of a composition can
migrate into an absorbing film, undergoes a catalytic reaction to
release a species, and the species can subsequently migrate back
into the composition. The species can be derived from the component
and/or from the matrix of the absorbing film.
[0026] Viscosity refers to interrelated non-Newtonian rheological
properties of a composition that can be time-dependent and/or
time-independent. For example, viscosity refers to dilatant,
rheopectic, and Bingham behavior.
[0027] Modified thin layers and methods of modifying thin layers
are disclosed.
[0028] A thin layer on a substrate and having a first composition
can be modified by applying a selectively absorbing film onto the
thin layer. Constituents of the first composition can be caused to
absorb into the selectively absorbing film such that the initial
thin layer is modified to have a second composition, where the
first composition the second composition are different. After the
composition of the thin layer has been modified, the selectively
absorbing film can be removed and the modified thin layer can be
subjected to further processing.
[0029] A thin layer can be provided on a substrate.
[0030] A substrate can comprise a planar surface or can comprise a
structured surface. A structured surface refers to a surface having
topographical surface features that can be raised above and/or
recessed below a nominal surface plane of the substrate. A
substrate surface can have any suitable topography as appropriate
for a particular application. For example, a substrate can comprise
a plurality of wells recessed below the nominal surface. The wells
can have any suitable dimensions. For example, the plurality of
wells can have a maximum dimension in the surface plane from 1
.mu.m to 4 .mu.m and can have a depth with respect to the substrate
surface from 1 .mu.m to 4 .mu.m. Each of the plurality of wells can
define a volume, for example, from 1 .mu.m.sup.3 to 64 .mu.m.sup.3,
from 3 .mu.m.sup.3 to 40 .mu.m.sup.3, from 6 .mu.m.sup.3 to 50
.mu.m.sup.3, or from 10 .mu.m.sup.3 to 40 .mu.m.sup.3. The wells
can have any suitable geometry such as, for example, round, oval,
square, rectangular, triangular, elliptical, a regular polygon, or
an irregular polygon.
[0031] For example, a well can have an aspect ratio from 10:1 to
1:10, from 8:1 to 1:8, from 6:1 to 1:6, from 4:1 to 1:4, from 3:1
to 1:3, from 2:1 to 1:2, or 1.5:1 to 1:1.5.
[0032] A well can have a maximum in-plane dimension, for example,
less than 5 .mu.m, less than 4 .mu.m, less than 3 .mu.m, less than
2 .mu.m, or less than 1 .mu.m.
[0033] A well can have a depth, for example, from 1 .mu.m to 10
.mu.m, from 1 .mu.m to 8 .mu.m, from 1 .mu.m, to 8 .mu.m, from 2
.mu.m to 6 .mu.m, or from 2 .mu.m to 4 .mu.m.
[0034] A well can have a depth that is the same as or greater than
the maximum in-plane dimension.
[0035] A substrate can be formed from any suitable material such
as, for example, a metal, a semiconductor, an inorganic material, a
ceramic, a thermoplastic, a thermoset, a composite, or a
combination of any of the foregoing. Because the methods disclosed
by the present disclosure can be carried out at room temperature
(25.degree. C.), at least with respect to the disclosed methods,
the thermal properties of the substrate material are not
particularly limiting. For example, a substrate may be formed of
glass, metal foil, metal foil covered with dielectric, or a polymer
such as polyethylene terephthalate (PET), polyethylene naphthalate
(PEN), polycarbonate (PC), polyethersulphone (PES), aromatic
fluorine-containing polyarylates (PAR), polycyclic olefin (PCO),
and polyimide (PI). A substrate can incorporate electronic
circuitry. A substrate can comprise any material or combination of
materials used in the electronic industry including, for example,
metals, semiconductors, dielectrics, and insulators.
[0036] A substrate can be, for example, an aluminum substrate
having 2 .mu.m.times.2 .mu.m wells with a depth of 2 .mu.m on a 5
.mu.m pitch. A substrate can be configured to provide a display
comprising a plurality of pixels.
[0037] A layer can have any suitable composition comprising two or
more constituents. A layer can be continuous such as in the form of
a sheet or thin film, or can be discontinuous such as in selected
regions on a substrate. For example, a layer includes a layer
comprising a composition deposited within wells disposed in a
substrate.
[0038] A layer composition can be viscous, having an initial
viscosity, for example, from 500 centipoise to 10,000 centipoise,
from 500 centipoise to 8,000 centipoise, from 500 centipoise to
6,000 centipoise, or from 500 centipoise to 4,000 centipoise. A
layer composition can have a viscosity, for example, greater than
500 centipoise, greater than 1,000 centipoise, greater than 2,500
centipoise, greater than 5,000 centipoise, or greater than 10,000
centipoise. A layer composition can have a relative low viscosity,
such as, for example, less than 1,000 centipoise, less than 500
centipoise, less than 200 centipoise, less than 100 centipoise, or
less than 50 centipoise. For example, a layer composition can have
a viscosity from 1 centipoise to 1,000 centipoise, from 5
centipoise to 800 centipoise, from 10 centipoise to 600 centipoise,
or from 50 centipoise to 500 centipoise. Viscosity can be measured
using an Anton Paar MCR 302 rheometer with a gap from 1 mm to 2 mm
at 25.degree. C. and a shear rate of 100 sec.sup.-1.
[0039] A thin layer can have sufficient internal integrity such
that when a selectively absorbing film is applied to the surface of
the layer, and subsequently removed, the modified layer remains
adhered to the underlying substrate. The composition can be
spreadable onto a substrate using a squeegee or other apparatus
that can push the composition across a surface and into recesses.
The deposition can be performed at any suitable temperature. The
composition can be have a sufficiently low viscosity such that it
can be spread onto a substrate or deposited onto a substrate using
method used to deposit low viscosity compositions such as by ink
jet printing. It can be desirable that the composition be
spreadable and able fill a plurality of wells recessed into a
substrate. For example, each of the plurality of wells can have a
width of 2 .mu.m.times.2 .mu.m with a depth of 2 .mu.m on a 5 .mu.m
pitch. The wells can be deeper such as can have a depth from 2
.mu.m to 100 .mu.m, from 2 .mu.m to 75 .mu.m, from 2 .mu.m to 50
.mu.m, or from 2 .mu.m to 25 .mu.m. The wells can have a width, for
example, from 2 .mu.m to 20 .mu.m, from 2 .mu.m to 15 .mu.m, from 2
.mu.m to 10 .mu.m, or from 2 .mu.m to 5 .mu.m. It can be
appreciated that different deposition methods and different
composition viscosities, as well as other factors such as surface
tension, can be selected depending on the dimensions of the wells
in which the composition is to be deposited.
[0040] A layer can comprise a curable composition such as a
thermoset, an inorganic composition, or a green ceramic. A curable
composition can be deposited onto a substrate to form a layer and
subsequently cured. Suitable cure mechanisms include, for example,
actinic radiation such as UV, coreactive chemistries, latent cure
mechanisms, and moisture cure mechanisms. Curing of a deposited
composition can occur without an independent initiation process, or
can occur using a separate initiation process such as by exposing
the deposited composition to UV radiation. Cure can be accelerated,
for example, by applying heat to the deposited composition
[0041] A layer can comprise a composition comprising one or more
constituents such as binders, curing agents, particles, solvent,
reactive diluents, rheology control agents, catalysts, dispersants,
light scattering agents, initiators, and combinations of any of the
foregoing.
[0042] A binder can comprise an organic binder, and can include
small molecules, prepolymers, and combinations thereof. Binders
refer to compounds that are reactive to form a cured polymeric
network or matrix. Small molecules can have a molecular weight, for
example, less than 1,000 Daltons, less than 800 Daltons, less than
600 Daltons, or less than 400 Daltons, Prepolymer can have a
molecular weight, for example, greater than 1,000 Daltons, greater
than 2,000 Daltons, greater than 4,000 Daltons, or greater than
6,000 Daltons. The binder can include coreactive components that
can be cured by heat, by actinic radiation, moisture-cure, or by
dark cure mechanism. The coreactive components can be based on any
suitable chemistry such as acrylate, polyurethane, polyurea,
thiol/ene, Michael addition, carbonate, epoxy/thiol, or epoxy/amine
curing chemistry. Suitable binders include, for example, melamines,
a phenols, alkyls, epoxies, polyurethanes, maleic acids,
polyamides, polymethyl methacrylates, polyacrylates,
polycarbonates, polyvinyl alcohols, polyvinylpyrrolidones,
hydroxyethylcellulose, carboxymethylcellulose,
carboxymethylcellulose, and monomers, homopolymers, copolymers, and
prepolymers of any of the foregoing. The binder can also comprise a
silicone.
[0043] A copolymerizable composition can be
photo-polymerizable.
[0044] A copolymerizable composition can be based on acrylate
chemistry and can include acrylate monomers and/or acrylate
oligomers.
[0045] A reactive diluent is a low molecular weight compound that
can be used to control the rheology and during curing can become
covalently bound to the polymeric network.
[0046] A catalyst can be any suitable catalyst for accelerating the
chemical reaction between the binder and the curing agent. In
UV-cure systems, the catalyst can be a photoinitiator.
[0047] A dispersant refers to a compound that facilitates the
dispersal of particles in the composition. A dispersant prevents or
minimizes agglomeration of the particles and facilitates the
ability of the particles to disperse homogenously throughout the
thin film composition.
[0048] Examples of suitable light scattering agents include
titanium dioxide, alumina, barium sulfate, polytetrafluoroethylene,
barium titanate and the like.
[0049] Examples of suitable rheology modifiers include fumed
silica, treated silica, and hydrophilic silica.
[0050] A layer can be in the form of paste or in the form of an
ink. For certain applications it can be desirable that a deposited
layer have a high particle content. For example, in electrically
conductive, electrooptic, and optoelectronic applications it can be
useful to have a high particle content to increase the electrical
conductivity of the layer and/or to increase the optical output of
a layer. A paste can have a relatively high viscosity and an ink
can be a colloidal suspension of particles.
[0051] A layer can comprise a particles. The particles can have any
suitable shape, such as cylindrical, lenticular, spheroidal,
planar, particulate, rod-shaped, flake, or other suitable shape.
Particles can comprise organic particles, inorganic particles,
metal particles, semiconductor particles, or composite particles.
Particles can be thermally conductive and/or electrically
conductive. Particles can be field-responsive such as, for example,
photoactive or electroactive. A photoactive particle is responsive
to radiation.
[0052] In certain applications, it can be desirable that an initial
layer composition have a high volume percent loading of particles.
For example, a high volume of a thermally conductive, electrically
conductive, photoactive filler, or electroactive particles can be
useful in enhancing the respective properties of a cured film
fabricated using the composition. An initial layer composition can
include, for example, an amount of particles from 1 vol % to 99 vol
%, from 10 vol % to 90 vol %, from 20 vol % to 80 vol %, or from 30
vol % to 70 vol %, where vol % is based on the volume of the
composition The amount of particles in the initial layer
composition can be limited, for example, by the method used to
apply the layer and/or the topography of the substrate to which the
layer composition is to be applied. For example, increasing amounts
of particles increase the viscosity of the layer composition, which
can make it difficult to apply the composition into small substrate
features. Although less viscous compositions can more easily fill
small substrate features, the vol % loading of the filler is also
less.
[0053] As a result, the vol % loading of filler in an initial layer
composition can be less than is desired for the final cured film.
For example, it can be desired that the final cured film have a vol
% loading of particle greater than 50 vol %, greater than 60 vol %,
greater than 70 vol %, greater than 80 vol %, greater than 90 vol
%, greater than 95 vol % or greater than 99 vol %. However, due to
constraints associated with the application method and/or the
surface topography, it may not be possible to obtain the desired
particle loading for the final product in the initially deposited
layer.
[0054] A layer can be applied to a substrate using any suitable
method. For example, the layer can be applied by spraying, by
dip-coating, by ink jet printing, by roller-coating, by
spin-coating, by transfer-printing, by spreading, or by any other
suitable method. An appropriate method can be determined by, for
example, the viscosity of the material being applied and by the
topography of the surface being coated.
[0055] An applied layer can have any suitable thickness as
appropriate for a particular application. For example, an applied
layer can have a thickness, less than 100 .mu.m, less than 50
.mu.m, less than 30 .mu.m, less than 20 .mu.m, less than 10 .mu.m,
or less than 5 .mu.m. A layer can have a thickness, for example,
from 0.5 .mu.m to 100 .mu.m, from 1 .mu.m to 50 .mu.m, from 2 .mu.m
to 20 .mu.m, or from 2 .mu.m to 10 .mu.m. The applied layer can be
continuous such as have a substantially constant thickness across a
planar surface. An applied layer can be discontinuous such that the
layer only covers a portion or portions of a surface. A
discontinuous layer can cover portions of a planar surface. A
discontinuous layer can cover or fill recesses in the substrate and
the nominal planar surface can have substantially no layer.
[0056] An applied layer can have any suitable thickness. The layer
can be relatively thin such that a selectively absorbing film can
modify the coating throughout the thickness of the layer. For
example, a thin layer can have a thickness less than 5 .mu.m, less
than 4 .mu.m, less than 3 .mu.m, less than 2 .mu.m or less than 1
.mu.m. In certain applications, it can be desirable that only the
top surface of the layer be modified. In these applications a
thicker coating can be used.
[0057] A selectively absorbing film includes one or more layers
configured to absorb one or more materials from a layer deposited
on a substrate. By selectively absorbing is meant that the two or
more materials forming the layer are not equally absorbed by the
selectively absorbing film. For example, some materials forming the
layer may be absorbed by the selectively absorbing film and other
materials may exhibit no appreciable absorption or only limited
absorption. Some materials may absorb at a faster rate into the
selectively absorbing film, while other materials may have a
relatively slower rate of absorption. Thus, when a selectively
absorbing film is applied to a layer, over a period of time,
certain constituents of the layer will be preferentially absorbed
by the selectively absorbing film, compared to other constituents.
Selective absorption can refer to selective absorption of small
molecules. For example, a solvent can be absorbed and monomeric
binders, rheology modifiers and/or other materials may not be
absorbed. For example, small molecules such as monomers may be
absorbed and larger molecules such as prepolymers may not be
absorbed. For example, a selectively absorbing film can selectively
absorb molecules based on molecular weight and/or by physical size.
As another example, organic components of a composition such as
solvents, binders, and others may be absorbed, possibly at
different rates, and particles may not be absorbed by the
selectively absorbing film. The selectively absorbing film may
absorb all small molecules in a composition, at least to some
extent, and not absorb the particles. In this way, particles can
become concentrated in the layer.
[0058] A selectively absorbing film can include a single layer or
can include multiple layers. The layers of a selectively absorbing
film can be selected based on absorptive properties, absorption
control properties, and/or physical properties. An absorbing layer
can be selected, for example, to absorb molecules based on size,
polarity, hydrophobicity, hydrophilicity, or a combination of any
of the foregoing. Examples of layers selected based on physical
properties include a support layer that provides structural
support. Each of the multilayer layers can independently have a
different thickness.
[0059] A selectively absorbing film can include a single layer. A
single layer of a selectively absorbing film can have a surface
that does not adhere to the deposited layer to be modified and that
selectively absorbs small molecules and does not adhere to the
deposited layer and/or to particles within the deposited layer.
[0060] Examples of suitable materials for single layer selectively
absorbing films include silicones, polymers having intrinsic
micro-porosity, metal-organic frameworks, and porous coordination
polymers.
[0061] A multilayer selectively absorbing film can include, for
example, a porous layer that does not adhere to the deposited
layer. A porous layer can exclude molecules based on molecular
weight and or size. Examples of such porous materials include
silica, polystyrene-divinyl benzene, and alumina. One or more
absorbing films can overly the porous layer. Porous layers,
absorbing layers, and selectively absorbing layers can be
interspersed throughout a multilayer selectively absorbing
film.
[0062] A selectively absorbing film can have any suitable
thickness. A suitable thickness can be determined, for example, by
the amount of material to be absorbed, the topography of the
surface on which the material layer is deposited, on the method
used to apply the selectively absorbing film to the coating, and on
the desired structural integrity. To facilitate the ability of a
selectively absorbing film to conform to surface topography it can
be desirable that a an absorbing film be thin.
[0063] FIG. 2A shows a multilayer selectively absorbing film 201
applied to a material layer 202 on a substrate 203. An example of a
multilayer selectively absorbing film 201 is shown in FIG. 2B. The
selectively absorbing film shown in FIG. 2B includes support layer
204, a first absorbing layer 205, a second absorbing layer 206, and
a release layer 207. Support layer 204 provides structural
integrity to the selectively absorbing film and can determine the
mechanical properties of the film. For example, the support layer
204 can be flexible to facilitate the ability of the film to
conform to a topography of an underlying surface. The support layer
204 can be substantially rigid to facilitate the ability of a load
applied to the film to be distributed evenly across the plane of an
underlying surface.
[0064] A support layer can comprise any suitable material that
provides mechanical integrity and that can facilitate handling of
the selectively absorbing film.
[0065] First absorbing layer 205 can be configured to absorb
molecules that are able to pass through the second absorbing layer
206. For example, molecules absorbed by the first absorbing layer
205 can have a smaller physical size than molecules capable of
being absorbed by the second absorbing layer 206.
[0066] The second absorbing layer 206 can be permeable to molecules
absorbed in the first absorbing layer. A second absorbing layer 206
may not absorb molecules to a significant extent but can serve as a
porous membrane that allows molecules to easily pass through the
layer and into the first absorbing layer, where the molecules
become sequestered.
[0067] The bottom layer 207 can be a porous layer that allows
molecules to pass through and into the overlying layers. The bottom
layer 207 can also function as a release layer and can be
configured to not adhere to the underlying surface.
[0068] A selectively absorbing film can comprise, for example, from
1 to 10 layers, from 1 to 6 layers, from 1 to 4 layers, or from 1
to 2 layers. A selectively absorbing film can comprise, for
example, 1, 2, 3. 4, 5, 6, 7, 8, 9, or 10 layers.
[0069] The thickness a layer of a selectively absorbing film can
be, for example, from 100 .mu.m to 1,200 .mu.m, from 200 .mu.m, to
1,000 .mu.m, from 300 .mu.m to 800 .mu.m, or from 400 .mu.m to 600
.mu.m.
[0070] A bottom layer can be uniform within the plane.
[0071] For certain applications, a bottom layer can be non-uniform
within the plane.
[0072] The bottom layer of a selectively absorbing film can be
treated to control absorption of materials in a layer and/or to
prevent or to minimize adhesion of the absorbing film to materials
in the layer.
[0073] For example, the bottom layer can be physically structured
such that the bottom layer does not have a uniform thickness. For
example, the bottom layer can include depressions and or cavities.
A physically structured bottom surface can be used tailor the
absorptive properties of the film to provide a structured modified
layer, such that the structured modified layer has non-uniform
properties and/or composition within the plane of the layer. A
physically structured bottom layer can facilitate contact of the
selectively absorbing film with a layer deposited within a cavity;
or conversely a physically structured bottom layer can prevent or
minimize contact of the selectively absorbing film with certain
regions of the layer.
[0074] A bottom layer can have non-uniform physical and/or material
properties within the plane of the film. For example, with the
plane of the film, certain regions can be permeable to molecules
within the deposited layer, and in other regions within the plane
of the film, the film can be impermeable to molecules within the
deposited layer. Non-uniform regions can be fabricated, for
example, by changing the cross-linking density of the polymeric
network of the bottom layer of the selectively absorbing film.
[0075] A bottom layer of a selectively absorbing film can comprise
a mask in which desired areas are removed to provide access to a
deposited layer. The mask material may be impermeable, partially
permeable, or selectively permeable with respect to certain or all
constituents of the layer.
[0076] An absorbing layer can comprise a semipermeable material
such as, for example, silicones, non-isocyanate polyurethanes
cellular polyurethanes, polyacrylic acids, and polyethylene
glycols. The semipermeable material can be in the form of sponges,
hydrogels or porous membranes. For example, silicones such as
polymethyl siloxanes are known to absorb non-polar solvent such as
hydrocarbons, toluene and dichloromethanol,
[0077] An selectively absorbing layer can be a porous layer and can
be made from materials that can separate materials by size.
[0078] A selectively absorbing film can be configured to
selectively transport molecules from a deposited layer based on
molecular size, surface energy, steric hindrance or a combination
of any of the foregoing.
[0079] Selectively absorbing films can be field-responsive. A
field-responsive selectively absorbing film refers to a film in
which the properties can be dynamically changed while the film is
applied to a layer. For example, an external field such as an
electrical, optical, microwave, inductive, or thermal field can be
applied to change a property of the selectively absorbing film or
change a property of a portion of a selectively absorbing film. The
application of an external field can change the pore size of one or
more layers of the film. In another example, a layer of the film
can include molecules that change conformation, for example by
absorption of radiation, and can thereby change the transport
properties of a film. Other molecules responsive to external fields
include liquid crystals and/or rotoxanes. Photoisomerization can be
used to control the transport properties of a film and/or can be
used to monitor the film. For example, it can be useful to actively
monitor the absorption of materials into the film to quantify the
amount of material being removed from the coating. In can be
desirable to monitor the absorption process. For example, this can
be accomplished using optical methods.
[0080] When a selectively absorbing film is applied to a coating a
concentration gradient can be produced such that components of the
coating can passively diffuse into the area of low concentration
within the selectively absorbing film. A selectively absorbing film
can change volume when in contact with certain materials that can
cause the absorbing film to swell.
[0081] A selectively absorbing film can be formed from a material
having a free volume that allows certain components to pass through
and/or be absorbed into the absorbing layers.
[0082] One or more absorbing layers of a selectively absorbing film
can include a solvent. The presence of a solvent in an absorbing
film can facilitate the ability of a component to diffuse into the
absorbing layers. A solvent can be selected to preferentially
solubilize a component or multiple components of the coating. A
solvent can be selected to modify the pore volume of an absorbing
layer. For example, certain solvents can cause a polymeric material
to swell.
[0083] The presence of a solvent in a selectively absorbing layer
can also maintain the integrity of the interface between the
selectively absorbing film and the coating during the absorption
process. For example, as materials are removed from the deposited
layer and absorbed into the selectively absorbing film, solvent
from the absorbing film can transfer into the interface and/or
transfer into the deposited layer.
[0084] A selectively absorbing film can be applied by any suitable
method. The method can include applying pressure to the selectively
absorbing film or may not involve applying pressure to the
selectively absorbing film. If pressure is applied, the pressure
may be applied selectively across the surface or may entail
applying pressure in certain regions across the surface. The
pressure may be applied to facilitate the ability of the
selectively absorbing film to physically contact a coating. A
selectively absorbing film may, when applied to the deposited
layer, have sufficient contact that it is not necessary to apply
pressure to the selectively absorbing film.
[0085] A selectively absorbing film can be applied to a substrate
using, for example, a platen, may be rolled onto the coating, may
be applied by vacuum, by spraying, or by spin coating. Applying a
selectively absorbing film in the form of a liquid or low-viscosity
material can facilitate the ability of the selectively absorbing
film to conform to surface topography. For example, when a layer is
disposed within small-dimensioned wells, a solid film may not be
able to sufficiently conform to enable contact with material
disposed within a well. Alternatively, a low viscosity, curable
composition can be applied to the substrate such that the curable
composition fills the wells and contacts the deposited layer within
the wells. The low viscosity, curable composition can then be cured
in place to provide a selectively absorbing film.
[0086] A selectively absorbing film having multiple layers may be
applied as a single film.
[0087] A selectively absorbing film having multiple layers can be
applied such that one or more of the multiple layers are applied
sequentially or at different times. For example, a first layer can
be applied and materials from the coating allowed to absorb into
the first absorbing layer. Then, a second absorbing layer can be
applied onto the first absorbing layer and materials allowed to
absorb into both the first and second absorbing layers. This can be
useful to produce a concentration gradient that can facilitate the
ability of materials to be absorbed into the selectively absorbing
film.
[0088] Furthermore, rather than use a selectively absorbing film
configured to absorb several materials having different properties,
it can be useful to have a variety of selectively absorbing films
with each film configured to optimize the absorption of a
particular material or materials from the coating. A first
selectively absorbing film can be applied to the layer, and a first
material or materials allowed to absorb into the first film. The
first film can then be removed and a second absorbing film applied
to the first modified layer, a second material or materials allowed
to absorb into the second film, to provide a second modified
layer.
[0089] To facilitate the ability of a selectively absorbing film to
contact an underlying layer, a solution may be applied to the
coating and/or onto the bottom surface of the selectively absorbing
film to provide an interfacial layer. Particularly when the surface
topography of the deposited layer is non-planar, such as in
recesses or wells on a substrate, the ability of the selectively
absorbing film to contact the layer can be facilitated by the
presence of an interfacial layer. The interfacial layer can be
formed of a material in which molecules that are intended to be
absorbed are soluble and therefore allows the molecules to flow
from the layer, across the interface, and into the selectively
absorbing film. The solution can also facilitate the ability of the
selectively absorbing film to maintain functional contact with the
layer as components of the layer are removed and the volume of the
layer decreases. This can be useful, for example, when a layer is
within a recess where it may be difficult to establish and maintain
physical contact between the layer and the selectively absorbing
film. The interface solution can comprise a volatile material to
facilitate removal of the interface after the selective absorption
process is complete.
[0090] A selectively absorbing film can be a film provided in the
form of a sheet or multiple sheets of material. The sheets can be
prepared by any suitable method such as, for example, by extrusion,
casting, or laminating A porous adhesive layer can be used to bond
adjacent films.
[0091] A selectively absorbing film can be provided as a system
including multiple separate or combined films that can be applied
separately and/or at different times during the process. For
example, a porous layer can be applied to the deposited layer and
overlying films can be added and/or removed.
[0092] A selectively absorbing film can be applied to a layer as a
liquid, which can be allowed to set or cure in place. The liquid
material can be applied, for example, using a spray, spin coating,
roller coating, or spreading. After a first selectively absorbing
material has been applied as a liquid and cured to a provide a thin
film, subsequent overlying films can be applied either as solid
films or from a liquid. An advantage of applying a selectively
absorbing film as a liquid or low viscosity material is that the
liquid can more readily conform to the surface topography. For
example, a liquid film can fill recesses in a substrate and thereby
make physical contact with a layer, at least initially, within a
recess.
[0093] After a selectively absorbing film is applied to a deposited
layer, one or more components of the layer can be allowed to
diffuse into the selectively absorbing film.
[0094] The diffusion can take place at room temperature (25.degree.
C.) or at higher temperatures. For example, the absorption can take
place at temperatures less than 50.degree. C., less than 40.degree.
C., less than 30.degree. C., or less than 25.degree. C. Although
higher temperatures can reduce the viscosity of the deposited
composition and in principle facilitate the selective absorption
process, higher temperatures can also accelerate thermal curing
reactions. Therefore, a suitable temperature can be selected based
on the materials used and the dynamics of the selective absorption
process
[0095] A slight pressure can be applied to the selectively
absorbing film, or no pressure can be applied. A slight pressure
can be useful to facilitate physical contact between the deposited
layer and the selectively absorbing film. However, compressing the
absorbing film can also reduce the free volume.
[0096] The slight pressure can be applied continuously,
intermittently, or repeatedly. For example, the pressure applied
can be varied at different times to maintain contact between the
selectively absorbing film and the deposited layer and/or to create
a pumping action that can facilitate the ability of components of
the deposited layer to move into the selectively absorbing
film.
[0097] To facilitate transport of the components during absorption
a the assembly can be vibrated. Vibration, including frequencies
from subsonic through ultrasonic, can help to reduce adhesion and
facilitate mixing of a deposited composition and facilitate
transport of the absorbed components into and through the layer(s)
of the selectively absorbing film.
[0098] To facilitate transport of components during absorption a
vacuum can be applied to the top surface of the selectively
absorbing film.
[0099] An example of the process steps for modifying a deposited
thin film using a selectively absorbing film provided by the
present disclosure is described in the following paragraphs and
certain aspects are illustrated in FIGS. 1A-1C. FIGS. 1A-1C show a
substrate 101, a deposited material layer 102 applied to the
substrate 101, and a selectively absorbing film 103 applied to the
material layer 102.
[0100] First, a substrate having a deposited layer to be modified
is provided. A substrate can be a planar surface or can have a
surface topography. For example, a substrate surface can comprise
elevations and/or depressions. The layer can have a substantially
constant thickness across the substrate surface, or can have a
varying thickness across the substrate surface. A substrate surface
can comprise a plurality of depressions or cavities, and the
plurality of depressions or cavities can be filled, entirely or
partially, with the material layer.
[0101] A selectively absorbing film can be applied onto the surface
of the layer. The selectively absorbing film can be applied to the
layer by any suitable method, which can in part be determined by
the physical properties of the film. For example, a flexible film
can be rolled across the surface of the coating or can be applied
as a planar sheet of material onto the surface of the layer. The
film may be applied to the layer with minimal pressure. In certain
embodiments, the film may be applied to the layer with a suitable
pressure. It may not necessary that the selectively absorbing film
be applied to the deposited layer with a pressure to facilitate
selective absorption. Application of a slight pressure can serve to
facilitate physical contact between the film and the layer, both
initially and during the absorption process.
[0102] In embodiments in which the selectively absorbing film is
structured, within the plane of the film and/or orthogonal to the
plane of the film, the selectively absorbing film can be aligned
with substrate features and/or coating features before being
applied to the deposited layer.
[0103] A selectively absorbing film can be substantially homogenous
within the plane of the film. For example, any cross-section of the
film orthogonal to the plane of the film, can have the same
physical structure and material properties across the profile. An
example of a homogeneous selectively absorbing film is a
selectively absorbing film comprising multiple planar material
layers that have been laminated together to form a single sheet.
When applied to a deposited layer that has a homogeneous physical
structure and material composition within the plane, the
selectively absorbing film and the deposited layer can interact
uniformly to provide a modified coating having substantially
uniform properties and composition.
[0104] A structured selectively absorbing film can be used to
provide a modified coating that has non-uniform properties and
composition within the plane of the modified coating. For example,
after a layer having a substantially uniform composition is applied
to a surface of a substrate, it can be desirable to modify the
applied layer in certain regions to provide a chemically structured
layer. This can be accomplished by applying a structured
selectively absorbing film onto the uniform layer. The structured
absorbing film can be configured to have regions or areas with
different absorptive properties such that after being applied to a
layer having homogeneous composition, following the non-uniform
selective absorption, the modified layer will have a structured
chemical composition.
[0105] Selectively absorbing films and methods of using the
selectively absorbing films can be used, for example, to remove
components from a deposited coating, to increase the density or
volume percent (vol %) of particles within a deposited layer,
and/or to introduce components into the deposited layer.
[0106] For example, a layer composition can comprise hydrophobic or
hydrophilic solvents to decrease the viscosity. A selectively
absorbing film can selectively absorb the small size, low molecular
weight, solvent molecules from the composition.
[0107] For example, UV curable compositions can be initiated by
free radical mechanisms and UV free radical photoinitiators can be
employed in such systems to catalyze UV cure. To some extent, these
reactions can be initiated by room lighting. To control the cure of
UV curable systems, it can be desirable to introduce the
UV-sensitive free radical imitators after the UV curable
composition is applied to a surface. This can be accomplished, for
example, by loading a selectively-permeable film provided by the
present disclosure with a UV photoinitiator into the composition
after it has been applied to a substrate. Under suitable conditions
the UV-photoinitiator can diffuse from the permeable film and into
the applied composition.
[0108] A selectively-permeable film can also be used to impart
properties to the surface of a deposited layer the that are not
necessarily present throughout the thickness of the coating. For
example, in certain applications it can be desirable that the
surface of a coating have a hardness, solvent resistance, optical
property such as reflectivity or scattering, or coloring, which may
be different than the rest of the deposited layer.
[0109] To accomplish this, for example, low molecular weight
cross-linking agents can be diffused into the surface of the
deposited layer in contact with the selectively absorbing film.
[0110] Vacuum can be used to extract volatile components after a
thin layer is applied to a surface. However, not all components are
volatile, and the high viscosity of the coating can prevent or
reduce diffusion of the volatile component to the layer
surface.
[0111] A permeable film provided by the present disclosure can be
used to exchange components with an applied composition. For
example, a permeable film can be used to introduce a component into
the applied composition and can be used to extract one or more
components from the applied composition.
[0112] A selectively absorbing film can be used to introduce
components into a layer.
[0113] A selectively absorbing film can comprise one or more
unbound components incorporated into one or more of the layers
forming the selectively absorbing film. A material in the absorbing
film can diffuse into the layer.
[0114] A layer can have a relatively high viscosity such as in the
form of a paste and have a relatively high concentration of filler.
Such materials can have a relatively high vol % of particles. For
example, for a well filled with a composition having a particle
content of 50 vol % and assuming that 75% of the carrier can be
removed, after the absorption process 37.5 vol % of the well is
free, where vol % is based on the volume of the well. A second
layer can be applied to fill the volume, thereby increasing the
particle content of the well from 50 vol % to 68.75 vol %.
[0115] A deposited layer can have a relatively low viscosity such
as in the form of an ink. For an ink, the vol % particles can be
about 10 vol %, such as from 5 vol % to 20 vol %. Repeated use of a
selectively absorbing film to remove the carrier can result in a
substantial increase in the vol % loading of the particles in the
layer.
[0116] A selectively absorbing film can incorporate a
non-functional exchange material. By non-functional is mean that
the material does not have a specific function in the modified
composition such as acting as a binder or a catalyst. A
non-functional exchange material can be used to fill and restore
the free volume created by the absorbed components. For example,
for a layer deposited in a well, when 50 vol % is removed by the
absorbing film, at some point during the absorption the vacuum
force will offset the absorbing force thereby preventing further
absorption. To prevent or minimize this phenomenon, a
non-functional material initially in the absorbing layer can
diffuse into the well and effectively exchange with the absorbed
components. It can be desirable, for example, that the
non-functional exchange material have a low vapor pressure to
facilitate subsequent removal from the modified coating.
[0117] A deposited composition can include a component that
facilitates the ability of the deposited composition to form a
deposited layer and/or to conform to substrate surface topography,
and the can be readily absorbed by the selectively absorbing film.
For example, such a component can be preferentially absorbed by the
selectively absorbing film, and the selectively absorbing film can
be engineered to facilitate the absorption of the component. Using
such co-engineered combinations of layer components and the
selectively absorbing film, the composition of the modified layer
following the selective absorption process can be more
intentionally controlled.
[0118] A non-functional exchange material can also serve the
purpose of maintaining functional contact between the deposited
layer and the absorbing film as the volume of the deposited layer
decreases during the extraction process. To facilitate removal of
the non-functional material, it can also desirable that the
non-functional exchange material do appreciably diffuse into the
modified layer. Therefore, a non-functional exchange material can
be selected to have a low solubility with the non-absorbed
materials in the modified layer.
[0119] Methods provided by the present disclosure can be used to
modify the composition of a layer after it is deposited onto a
surface.
[0120] Depending on the method of application a composition can
include components that facilitate the deposition process but that
are either not useful or not desired in a cured product.
[0121] For example, compositions can include additives such as
solvents and rheology modifiers that are useful to reduce the
viscosity and/or improve the ability of a layer to fill a surface
topography.
[0122] Such additives may not bind to a cured network and may leach
from the matrix with time.
[0123] In can be desirable that these additives be removed from the
layer.
[0124] Methods provided by the present disclose can be used to
increase the concentration of a filler within a volume. Due to
surface adhesion, fillers can significantly increase the viscosity
of a composition, placing limits on the vol % loading of a
particular type of particle can be used with a particular
application method. Again, additives such as solvents and rheology
modifiers can be incorporated into a composition comprising
particles, and it can be useful that these additives be removed,
whether or not an objective is to increase the vol % loading of the
layer in a layer.
[0125] Alternatively, rather than fill the removed volume with a
solvent, the volume can be filled with air. The selectively
absorbing film can be sufficiently porous such that air can pass
through the film to fill the decreasing volume. In this scenario,
continued extraction of components from the layer can take place at
the meniscus.
[0126] A modified layer can have a concentration of low molecular
weight components, hydrophobic components, hydrophilic contents or
combinations of any of the forgoing that is less than the
concentration of the respective components in the initial
as-applied, deposited layer.
[0127] A modified coating can occupy a volume that is less than the
respective volume of the initial layer.
[0128] A modified layer can have a higher vol % particle content
than the vol % particle content of the applied layer, wherein vol %
is based on the volume of the relevant layer or portion
thereof.
[0129] A layer may be designed to be modified by one or more the
absorbed components. For example, a saponin or fatty acid in the
layer can bind to the matrix of the absorbing film through a
hydrophilic moiety, resulting in the hydrophobic end being
presented to the interior of the channels or pores of the matrix
thereby rendering the matrix more hydrophobic. This can result in
tailoring the properties of the matrix in a sequential fashion such
that a hydrophobic surface becomes hydrophilic during the
absorption process. This change in properties may be used to limit
or augment the absorption of other components or can be used as a
selective gate that maintains a hydrophobic molecule in an
absorbing layer more remote from the deposited layer from diffusing
into the deposited layer until after the molecule that alters the
hydrophobicity of the more proximal layer is absorbed from the
deposited layer.
[0130] An initial, as deposited, thin layer can have no particles,
or can have a particle content, for example, from 1 vol % to 99 vol
%, such as from 5 vol % to 95 vol %, 10 vol % to 90 vol %, 15 vol %
to 85 vol %, 20 vol % to 80 vol %, or from 20 vol % to 70 vol
%.
[0131] A particle can include organic particles, inorganic
particles, ceramic particles, metal particles, semiconductor
particles, or a combination of any of the foregoing.
[0132] Examples of suitable organic particles include
thermoplastics, thermosets, or a combination thereof. Examples of
suitable organic particles include epoxies, epoxy-amides, ETFE
copolymers, polyethylenes, polypropylenes, polyvinylidene
chlorides, polyvinylfluorides, TFE, polyamides, polyimides,
ethylene propylenes, perfluorohydrocarbons, fluoroethylenes,
polycarbonates, polyetheretherketones, polyetherketones,
polyphenylene oxides, polyphenylene sulfides, polyether sulfones,
thermoplastic copolyesters, polystyrenes, polyvinyl chlorides,
melamines, polyesters, phenolics, epichlorohydrins, fluorinated
hydrocarbons, polycyclics, polybutadienes, polychloroprenes,
polyisoprenes, polysulfides, polyurethanes, isobutylene isoprenes,
silicones, styrene butadienes, liquid crystal polymers, and
combinations of any of the foregoing.
[0133] Examples of suitable inorganic particles include carbon
black, calcium carbonate, precipitated calcium carbonate, calcium
hydroxide, hydrated alumina (aluminum hydroxide), fumed silica,
silica, precipitated silica, silica gel, and combinations of any of
the foregoing. For example, an inorganic particle can include a
combination calcium carbonate and fumed silica, and the calcium
carbonate and fumed silica can be treated and/or untreated. An
inorganic filler can comprise calcium carbonate and fumed silica.
An inorganic filler can be coated or uncoated. For example, an
inorganic filler can be coated with a hydrophobic material, such as
a coating of polydimethylsiloxane. Inorganic fillers useful in
compositions include carbon black, calcium carbonate, precipitated
calcium carbonate, calcium hydroxide, hydrated alumina (aluminum
hydroxide), fumed silica, silica, precipitated silica, silica gel,
and combinations of any of the foregoing. For example, an inorganic
filler can include a combination calcium carbonate and fumed
silica, and the calcium carbonate and fumed silica can be treated
and/or untreated.
[0134] Examples of suitable ceramic particles include zirconium
dioxide, boron carbide, silicon nitride, hydroxyapatite, alumina,
and aluminosilicates.
[0135] Suitable particles include low-density particles,
electrically conductive particles, optically response particles, or
a combination of any of the foregoing. Low density particles can
have, for example, a specific gravity less than 1.0, less than
0.75, or less than 0.5.
[0136] Examples of suitable electrically conductive particles
include copper, nickel, silver, aluminum, tin, nickel powder,
graphite, nickel-coated graphite, stainless steel, or a combination
of any of the foregoing. Electrically conductive fillers also
include high band gap materials such as zinc sulfide, inorganic
barium compounds, zinc oxide, tin oxide, and combinations of
conductive particles. Other examples of electrically conductive
fillers include electrically conductive noble metal-based fillers
such as pure silver; noble metal-plated noble metals such as
silver-plated gold; noble metal-plated non-noble metals such as
silver plated cooper, nickel or aluminum, for example,
silver-plated aluminum core particles or platinum-plated copper
particles; noble-metal plated glass, plastic or ceramics such as
silver-plated glass microspheres, noble-metal plated aluminum or
noble-metal plated plastic microspheres; noble-metal plated mica;
and other such noble-metal conductive fillers. Non-noble
metal-based materials can also be used and include, for example,
non-noble metal-plated non-noble metals such as copper-coated iron
particles or nickel-plated copper; non-noble metals, e.g., copper,
aluminum, nickel, cobalt; non-noble-metal-plated-non-metals, e.g.,
nickel-plated graphite and non-metal materials such as carbon black
and graphite. Combinations of electrically conductive fillers can
also be used to meet the desired conductivity, EMI/RFI shielding
effectiveness, hardness, and other properties suitable for a
particular application.
[0137] Particles can include pigment, phosphors, electroactive
particles, magnetic particles, quantum dots, nano-diamonds,
photonic crystals, and combinations of any of the foregoing.
[0138] A phosphor refers to any type of wavelength converting
material capable of absorbing light of at least one wavelength and
capable of emitting light at another wavelength. Examples of
phosphors include quantum dots, which are semiconductor materials
having a size, composition, and structure in which the electrical
and optical characteristics differ from the bulk properties due to
quantum confinement effects. Fluorescence of quantum dots results
from the excitation of a valence electron by light absorption,
followed by the emission at a lower energy wavelength as the
excited electrons return to the ground state. Quantum confinement
causes the energy difference between the valence and conduction
bands to change depending on the size, composition and structure of
a quantum dot. For example, the larger the quantum dot, the lower
the energy of its fluorescence spectrum. The photoluminescence
emission wavelength of a quantum dot can have a sharp emission
spectrum and exhibit a high quantum efficiency.
[0139] Quantum dots can have any suitable geometry such as, for
example, rods, disks, prolate spheroids, and crystalline,
polycrystalline, or amorphous nanoparticles that can convert light
at a suitable wavelength or range of wavelengths, absorb selected
wavelengths of light, and/or convert one form of energy into
another.
[0140] Examples of quantum dot semiconductor materials include, for
example, Groups II-VI, III-V, IV-VI semiconductor materials.
Suitable quantum dot materials include CdS, CdSe, CdTe, ZnS, ZnSe,
ZnTe, GaAs, GaP, GaAs, GaSb, HgS, HgSe, HgTe, InAs, InP, InSb,
AlAs, AlP, and AlSb. Other examples of suitable quantum dot
materials include InGaP, ZnSeTe, ZnCdS, ZnCdSe, and CdSeS.
Multi-core structures are also possible. Examples of multicore
quantum dot configurations include a quantum dot having a
semiconductor core material, a thin metal layer to protect the core
from oxidation and to facilitate lattice matching, and a shell to
enhance the luminescence properties. The core and shell layers can
be formed from the same material, and may be formed, for example,
from any of the listed semiconductor materials. A metal layer can
comprise Zn or Cd.
[0141] Ligands can be bound to quantum dots, for example, to
promote ligands to promote solubility of the quantum dots in the
polymerizable composition, which can provide for higher vol %
loadings without agglomeration. Ligands can be derived from a
coordinating solvent that may be included in the reaction mixture
during the growth process. Examples of suitable ligands include
fatty acid ligands, long chain fatty acid ligands, alkyl
phosphines, alkyl phosphine oxides, alkyl phosphonic acids, alkyl
phosphinic acids, pyridines, furans, and amines. Specific examples
include pyridine, tri-n-octyl phosphine (TOP), tri-n-octyl
phosphine oxide (TOPO), tris-hydroxylpropylphosphine (tHPP) and
octadecylphosphonic acid ("ODPA"). Technical grade TOPO can be
used.
[0142] Examples of other phosphor particles include phosphors that
intrinsically exhibit photoluminescence because of the composition.
Examples of phosphor particles that exhibit luminescence due to the
composition include sulfides, aluminates, oxides, silicates,
nitrides, YAG (optionally doped with cerium), and terbium aluminum
garnet (TAG) based materials. Other exemplary materials include
yellow-green emitting phosphors: (Ca,Sr,Ba)Al.sub.2O.sub.4:Eu,
(Lu,Y) 3Al.sub.5O.sub.12:Ce.sub.3.sup.+(LuAG, YAG),
Tb.sub.3Al.sub.5O.sub.12:Ce.sup.3+(TAG); orange-red emitting
phosphors: BaMgAl.sub.10O.sub.17:Eu.sup.2+(Mn.sub.2.sup.+),
Ca.sub.2Si.sub.5N.sub.8:Eu.sup.2+, (Zn,Mg)S:Mn,
(Ca,Sr,Ba)S:Eu.sup.2+; UV-deep blue absorbing phosphors for blue
and yellow-green emission: (Mg,Ca,Sr,Ba).sub.2SiO.sub.4:Eu.sup.2+,
(Mg,Ca,Sr,Ba).sub.3Si.sub.2O.sub.7:Eu.sup.2+,
Ca.sub.8Mg(SiO.sub.4).sub.4Cl.sub.2:Eu.sup.2+; and phosphors that
can emit over the full visible spectrum depending on composition
and processing (Sr,Ca,Ba)Si.sub.xO.sub.yN.sub.z:Eu.sup.2+,
Y.sub.2O.sub.2S:Eu.sup.3+,
(Ca,Mg,Y).sub.vSi.sub.wAl.sub.xO.sub.yNz:Eu.sup.2. A phosphor
particle can have a dimension of from 1 .mu.m to 20 .mu.m. A
phosphor particle have a dimension of from 100 nm to 1 .mu.m. A
phosphor particles can be combination of phosphors having different
particles sizes.
[0143] Suitable particles can have any suitable geometric profile.
For example, particles can be substantially spherical,
substantially non-spherical, rod-shaped, oblong, or flake.
[0144] Particles can have any suitable dimension. For example,
particles can have dimensions, for example, from 1 nm to 1,000 nm,
from 1 nm to 750 nm, from 1 nm to 500 nm, from 1 nm to 400 nm, from
1 nm to 300 nm, from 1 nm to 200 nm, from 1 nm to 100 nm, from 1 nm
to 50 nm, or from 1 nm to 25 nm.
[0145] Selectively absorbing films can be used to increase the
amount and density, such as vol %, of particles within a volume.
Increasing the vol % loading of particles in a layer can be useful
when the increasing the density can significantly increase a
desired property of the layer. For example, increasing the density
of an electrically conductive particles can dramatically increase
the electrical conductivity of the volume. As another example,
increasing the density of an electroactive particle such as a
quantum dot, can dramatically increase the light output of the
volume. For example, in display applications it can be useful to
obtain a high light output per area. This can be achieved, with
certain limitations, by increasing the number of light emitting
materials underlying the area such as within a volume underlying
the viewing area. A low vol % of the light emitting particles can
require a higher volume to achieve a desired light output. However,
in certain displays, having a thin dimensions can be desirable and
therefore the intensity of a pixel cannot be increased by
increasing the volume underlying the pixel. In such designs, it can
be desirable to increase the vol % loading of the light emitting
materials to obtain a desired light output in a small volume as
determined by the dimensions of a thin display.
[0146] For certain applications it can be desirable to fill a
volume such as a cavity in a substrate with a high volume of
particles. High particle content increases the viscosity of a
composition, and it is difficult to fill cavities using viscous
materials. Although low viscosity materials and rheology modifiers
can be used in the composition to mitigate the effects of high
particle content, the content of the particles can be less than
desirable.
[0147] One approach to increase the particle content of a deposited
composition is to remove certain materials other than the
particulates from the composition after it has been applied to a
surface such as a cavity in the substrate. Removing certain
materials from the deposited composition can reduce the volume of
the remaining composition and thereby increase the vol % particle
content of the modified composition, but not necessarily the vol %
particle content of the initially filled volume such as a volume of
a cavity. For example, removing 50 vol % of the low molecular
weight, low viscosity, constituents of the initial composition will
leave the cavity with the same vol % particulate content, and will
leave the cavity only 50% filled.
[0148] The vol % particulate content of the cavity can then be
increased by applying or depositing a second volume of the initial
unmodified composition into the free volume in the cavity created
by removing the low molecular weight components. In this way, the
vol % particle content within the cavity can be increased by 50%.
Further cycles of removing components of the initial composition
and refilling the free volume can be used to increase the vol %
particle content within the cavity.
[0149] Methods provided by the present disclosure can be used to
increase the density of the particles in a deposited thin layer.
For example, the thin layer can comprise particles and various
other constituents such as constituents effective in reducing the
viscosity of the particle-containing composition to facilitate
depositing the thin film onto the substrate and in particular onto
a structured substrate. After the filler-containing composition is
deposited onto the substrate surface, a selectively absorbing layer
can be applied to the thin film. The selectively absorbing film can
abstract at least some of the non-filler content of the thin film
such as solvent and low molecular weight species such as
rheological control agents. For example, the selectively absorbing
film can abstract from 1 vol % to 70 vol %, from 5 vol % to 60 vol
%, from 10 vol % to 50 vol %, or from 20 vol % to 40 vol % of the
constituents of the deposited thin film. The density of the filler
can thereby be increased.
[0150] Particles includes surface-modified particles. Particle can
be modified to improve the compatibility such as dispersibility, of
the particles with the thin film composition, such as binding to
the surrounding matrix. Particles can be modified to bind to other
particles.
[0151] As can be appreciated, densifying electrically conductive
and optically responsive particles can be used to improve the
electronic and optical properties of the thin films into which they
are incorporated. Densifying electrically conductive thin films can
reduce the surface resistivity and through resistance, and
densifying optically responsive particles can increase the light
output power (LOP) per unit area.
[0152] In a deposited layer having a high vol % content of
particles it can be useful to have a binder to maintain the
integrity of the layer. Thus, it can be desirable that a certain
amount of the co-reactive components forming the binder remain in
the layer. The coreactive components can be small molecules, which
remain in the modified coating after the selective absorption
process. The coreactive components can be prepolymers, which remain
in the modified coating after the selective absorption process.
[0153] A deposited layer can include particles and small molecules
and a selectively absorbing film can absorb the small molecules to
about the same extent. Thus, after the selective absorption process
the composition of the small molecules will not change, and only
the concentration of the filler in the coating will increase. In
this example, the small molecules can include co-reactive
components of a binder, solvent, rheology modifiers, and
catalysts.
[0154] A deposited layer can include particles, large molecules,
and small molecules and a selectively absorbing film can absorb
primarily the small molecules. After the selective absorption
process the small molecules will preferentially be removed, and the
modified layer will include primarily the filler ant the large
molecules. In this example, the large molecules can comprise
coreactive components of the binder, and the small molecules can
include solvent, rheology modifiers, and catalysts.
[0155] Depending on the size of the particles, removal of
non-particle components of the layer can be facilitated by applying
a vacuum to the selectively absorbing film. Components of the layer
that are accessible to the pores of the absorbing film can be
removed from the coating.
[0156] An example of a process flow for preparing a modified layer
is shown in FIGS. 6A-6F. FIG. 6A shows a substrate 601 having an
open well 602. The substrate can be any suitable material such as,
for example, a metal or a semiconductor. As shown in FIG. 6B, layer
of material 603 comprising, for example, particulates can be
deposited within the well using any suitable method including those
disclosed herein. As shown in FIG. 6C, after layer 603 is deposited
within well 602, and absorbing film having a first layer 604 and a
second layer 605 can be applied onto layer 603. Components from the
deposited layer 603 can then be absorbed into the absorbing film
604/605 causing the volume of the absorbing film to decrease and
effectively increasing the density of particulates within the
layer. FIG. 6D shows an example of the structure during and/or
following the absorption process. FIG. 6E shows a cross-section of
modified layer 603A having a higher concentration of particulates
and/or other component than in the initially deposited layer 603.
As shown in FIG. 6F, another layer of material 603B can be applied
onto modified layer 603A. Material 603B can have the same
composition, for example, as material 603. In this way, the
concentration of particulates and/or components can be increased
within the well.
[0157] Methods provided by the present disclosure can be used to
fabricate pixels of a display.
[0158] As an example, a periodic array of wells can be fabricated
in a substrate in a desired arrangement for the display pixels. For
example, wells can be 2 .mu.m.times.2 .mu.m wide and 2 .mu.m deep
on a 5 .mu.m pitch and fabricated in a aluminum substrate.
[0159] Photo-responsive materials such as quantum dots can be
deposited within the wells. When illuminated with a light source
such as an LED the quantum dots can radiate at a desired wavelength
depending on the composition and the structure of the quantum
dot.
[0160] Lighting and display applications can include a wavelength
conversion layer comprising phosphor particles, such as quantum
dots, dispersed within a glass or polymer matrix. The phosphors can
be arranged into groups of phosphors that emit a different color
emission spectrum.
[0161] A light emitting device such as a display can include an
array of pixels with each pixel comprising a plurality of subpixels
designed for different color emission spectra. Each subpixel can
comprise a well in a substrate containing phosphor particles, and
different subpixels of a pixel can contain phosphor particles
capable of emitting a different color emission spectrum.
[0162] Quantum dots can be applied to a substrate from a
polymerizable composition. In addition to the quantum dots, the
polymerizable composition can include co-reactive binders,
cross-linking agents, scattering agents, rheology modifiers,
catalysts, filler, photoinitiator, or combinations of any of the
foregoing. The materials can be selected so as to absorb or to have
minimal absorption at the irradiated wavelength and the emission
wavelength of the quantum dots.
[0163] Other materials can be dispersed within the wavelength
conversion layer. For example, a light scattering agent such as
TiO.sub.2 or Al.sub.2O.sub.3 particles can be dispersed within the
wavelength conversion layer. Light scattering agents can increase
the phosphor particle efficiency by increasing light scattering
within the wavelength conversion layer. Light scattering agents can
also reduce transmission of the incident light through the
wavelength conversion layer. A pigment or dye can be dispersed
within the wavelength conversion layer. A pigment can act as a
color filter and can have, for example, a color similar to the
emission wavelength of the phosphor particle. The pigment or dye
can absorb at wavelength other than those being emitted from the
phosphor particle, further narrowing the emission spectrum of the
pixel.
[0164] For example, the other materials may be dispersed within the
matrix material, such as glass or polymer matrix of the wavelength
conversion layer.
[0165] A wavelength conversion layer can be incorporated into a
variety of lighting or display devices. Examples of lighting
applications include interior or exterior lighting applications,
such as billboard lighting, building lighting, street lighting,
light bulbs, and lamps. Examples of display applications include
passive matrix display and active matrix displays, such as display
signage, display panels, televisions, tablets, phones, laptops,
computer monitors, kiosks, digital cameras, handheld game consoles,
media displays, electronic book displays, and large area signage
display.
EXAMPLES
[0166] Embodiments provided by the present disclosure are further
illustrated by reference to the following examples, which describe
methods, compositions, and devices provided by the present
disclosure. It will be apparent to those skilled in the art that
many modifications, both to materials, and methods, may be
practiced without departing from the scope of the disclosure.
Example 1
Quantum Dot Optical Display
[0167] Quantum dot displays were fabricated using the materials and
methods provided by the present disclosure.
[0168] The substrate consisted of an thick aluminum film with
circular cavities having a 1.8 .mu.m diameter and a depth of 1.6
.mu.m on a 5 .mu.m pitch.
[0169] The coating composition was prepared by combining one or
more acrylates such as vinyl neodecanoate, hexylacrylate, octyl
acrylate, lauryl acrylate, bornyl methacrylate, and/or hexadecene,
a UV photoinitiator such as Irgacure.RTM. 179 and/or Irgacure.RTM.
1871, and quantum dots. The weight of the composition was about
1.5-times the weight of the quantum dots. The quantum dots formed a
colloidal suspension, which was determined by the concentration at
which the quantum dots began to precipitate. The composition
included about 10 wt % of the photoinitiator.
[0170] The coating composition was applied to the substrate using a
blade made of polydimethylsiloxane (Sylgard.RTM. 184, Dow
Chemical). The coating composition was gently spread over the
surface of the substrate by hand using the blade with a slight
pressure.
[0171] The thin coating was applied to fill the cavities and to
minimize the amount of ink outside the cavities and left on the top
surface of the substrate.
[0172] FIGS. 3A and 3B show photographs of cross-sections of
cavities containing a thin layer after deposition and before a
selectively absorbing film was applied to the deposited layer. The
cavities 301 shown in the figures within the aluminum substrate 302
have a width of about 1.6 .mu.m and a depth of about 1.6 .mu.m. The
composition comprising quantum dots is shown to completely fill the
cavity.
[0173] A selectively absorbing film was prepared by molding a 500
.mu.m thick sheet of Sylgard.RTM. 184 using the process recommended
by the manufacturer.
[0174] The selectively absorbing film was applied to the quantum
dot-containing layer by rolling the selectively absorbing film onto
the surface.
[0175] After a period of time the selectively absorbing film was
observed to swell and to increase in weight, indicating that
components of the quantum dot-containing layer became absorbed into
the selectively absorbing film.
[0176] As evidenced by the absence of fluorescence upon exposure to
a blue light source (440 nm at 5 mW) the quantum dots did not
adhere to the selectively absorbing film after it was removed.
[0177] FIGS. 4A and 4B show photographs of a display comprising a
plurality of 2 .mu.m-wide, 2 .mu.m-deep pixels fabricated using
methods provided by the present disclosure. FIG. 4A shows a
photograph of the display imaged with a 20.times. objective and
FIG. 4B shows a portion of the display imaged with a 50.times.
objective.
[0178] FIGS. 5A and 5B show photographs of another display
comprising a plurality of 10 .mu.m-wide, 2 .mu.m-deep pixels
fabricated using methods provided by the present disclosure. FIG.
5A shows a photograph of the display imaged with a 20.times.
objective and FIG. 5B shows a portion of the display imaged with a
50.times. objective.
ASPECTS OF THE INVENTION
[0179] Aspect 1. A method of modifying the composition of a layer,
comprising: (a) applying a selectively absorbing film in proximity
to a layer, wherein the layer comprises a first composition,
wherein the first composition comprises two or more components; and
(b) modifying the first composition by causing at least one of the
two or more components to absorb into the selectively absorbing
film, causing a component to absorb into the first composition; or
a combination thereof; to provide a modified layer, wherein the
modified layer comprises a second composition.
[0180] Aspect 2. The method of aspect 1, wherein modifying
comprises purifying the first composition, concentrating one or
more components of the first composition, removing one or more
components from the first composition, densifying a component of
the first composition, introducing one or more components into the
first composition, or a combination of any of the foregoing.
[0181] Aspect 3. The method of any one of aspects 1 to 2, wherein
modifying comprises extracting one or more low molecular weight
components from the first composition.
[0182] Aspect 4. The method of any one of aspects 1 to 3, wherein
modifying comprises extracting, from the first composition, small
molecules, prepolymers, solvents, rheology control agents, or a
combination of any of the foregoing.
[0183] Aspect 5. The method of any one of aspects 1 to 4, wherein
modifying comprises decreasing a volume of the layer.
[0184] Aspect 6. The method of any one of aspects 1 to 5, wherein
modifying comprises concentrating one or more components of the
first composition.
[0185] Aspect 7. The method of any one of aspects 1 to 6, wherein
modifying comprises removing one or more components from the first
composition.
[0186] Aspect 8. The method of any one of aspects 1 to 7, wherein
modifying comprises adding one or more components to the first
composition.
[0187] Aspect 9. The method of any one of aspects 1 to 8, wherein
the first composition and the second composition comprise an
unreacted thermoset composition.
[0188] Aspect 10. The method of any one of aspects 1 to 9, wherein
the first composition comprises a vol % loading of particles from 1
vol % to 90 vol %.
[0189] Aspect 11. The method of any one of aspects 1 to 10, wherein
the first composition comprises a first vol % of particles; the
second composition comprises a second vol % of particles; and the
second vol % is greater than the first vol %.
[0190] Aspect 12. The method of any one of aspects 10 to 11,
wherein the particles comprises a photoactive material.
[0191] Aspect 13. The method of any one of aspects 10 to 12,
wherein the particles comprise quantum dots.
[0192] Aspect 14. The method of any one of aspects 1 to 13, wherein
the layer has a thickness from 1 .mu.m to 500 .mu.m.
[0193] Aspect 15. The method of any one of aspects 1 to 14, wherein
the layer has a thickness less than 10 .mu.m.
[0194] Aspect 16. The method of any one of aspects 1 to 15, wherein
the layer comprises a continuous layer.
[0195] Aspect 17. The method of any one of aspects 1 to 16, wherein
the layer comprises a discontinuous layer.
[0196] Aspect 18. The method of any one of aspects 1 to 17, wherein
the layer is disposed within one or more recesses.
[0197] Aspect 19. The method of aspect 18, wherein the layer is
disposed within one or more recesses, wherein the recesses have a
depth from 1 .mu.m to 4 .mu.m and a width from 1 .mu.m to 4
.mu.m.
[0198] Aspect 20. The method of any one of aspects 1 to 19, wherein
applying a selectively absorbing film in proximity to the layer
comprises placing the film in contact with the layer.
[0199] Aspect 21. The method of any one of aspects 1 to 20, wherein
applying a selectively absorbing film in proximity to the layer
comprises placing the film near the layer.
[0200] Aspect 22. The method of any one of aspects 1 to 20, wherein
applying a selectively absorbing film comprises placing a solid
selectively absorbing film in proximity to the layer.
[0201] Aspect 23. The method of any one of aspects 1 to 22, wherein
applying a selectively absorbing film comprises depositing a liquid
film onto the layer.
[0202] Aspect 24. The method of aspect 23, further comprising
curing the liquid film to provide a solid selectively absorbing
film.
[0203] Aspect 25. The method of any one of aspects 1 to 24, wherein
the selectively absorbing film comprises a single layer.
[0204] Aspect 26. The method of any one of aspects 1 to 24, wherein
the selectively absorbing film comprises two or more layers.
[0205] Aspect 27. The method of any one of aspects 1 to 26, wherein
applying the absorbing film comprises applying two or more
selectively absorbing films sequentially.
[0206] Aspect 28. The method of any one of aspects 1 to 27, wherein
applying comprises pressing the selectively absorbing film onto the
layer
[0207] Aspect 29. The method of any one of aspects 1 to 28, wherein
the selectively absorbing film has a total thickness from 1 .mu.m
to 1 mm.
[0208] Aspect 30. The method of any one of aspects 1 to 29, wherein
the selectively absorbing film is structured within the plane of
the selectively absorbing film.
[0209] Aspect 31. The method of any one of aspects 1 to 30, wherein
the selectively absorbing film comprises multiple layers.
[0210] Aspect 32. The method of any one of aspects 1 to 31, wherein
the selectively absorbing film comprises: a release layer; one or
more absorbing layers overlying the release layer; and a structural
layer overlying the one or more absorbing layers.
[0211] Aspect 33. The method of aspect 32, wherein the release
layer, the one or more absorbing layers, the structural layer, or a
combination of any of the foregoing is field-responsive.
[0212] Aspect 34. The method of any one of aspects 1 to 33, wherein
the selectively absorbing film comprises one or more
field-responsive layers.
[0213] Aspect 35. The method of aspect 34, wherein the one or more
field-response layers comprises a field-responsive compound.
[0214] Aspect 36. The method of aspect 35, wherein the
field-responsive compound comprises liquid crystals, rotaxanes,
field switchable molecules, or a combination of any of the
foregoing.
[0215] Aspect 37. The method of any one of aspects 34 to 36,
wherein each of the one or more field-responsive layers is
configured to control a property of the field-responsive layer in
response to an externally applied stimulus.
[0216] Aspect 38. The method of aspect 37, wherein the property
comprises wetting, porosity, surface energy, surface charge, bulk
modulus, surface stress, or a combination of any of the
foregoing.
[0217] Aspect 39. The method of any one of aspects 37 to 38,
wherein, each of the one or more field-responsive layers is
configured to control the porosity of the selectively absorbing
film; and the porosity is associated with a change in pore size
distribution, channel connectivity, effective channel surface area,
a change in surface affinity, or a combination of any of the
foregoing.
[0218] Aspect 40. The method of any one of aspects 1 to 39, wherein
causing comprises passive diffusion.
[0219] Aspect 41. The method of any one of aspects 1 to 39, wherein
causing comprises active diffusion.
[0220] Aspect 42. The method of any one of aspects 1 to 41, wherein
causing comprises maintaining a temperature of the layer at less
than 30.degree. C.
[0221] Aspect 43. The method of any one of aspects 1 to 41, wherein
causing comprises maintaining a temperature of the layer from
20.degree. C. to 28.degree. C.
[0222] Aspect 44. The method of any one of aspects 1 to 41, wherein
causing comprises heating the layer and the absorbing film.
[0223] Aspect 45. The method of any one of aspects 1 to 44, wherein
causing comprises applying a vacuum to the selectively absorbing
film.
[0224] Aspect 46. The method of any one of aspects 1 to 45, wherein
causing comprises applying an electromagnetic field to the layer,
the selectively absorbing film, or a combination thereof.
[0225] Aspect 47. The method of any one of aspects 1 to 45, wherein
causing comprises applying an electrical field to the layer, the
selectively absorbing film, or a combination thereof.
[0226] Aspect 48. The method of any one of aspects 1 to 45, wherein
causing comprises applying a magnetic field to the layer, the
selectively absorbing film, or a combination thereof.
[0227] Aspect 49. The method of any one of aspects 1 to 48, wherein
the first composition comprises a first reactive component and a
second reactive component, wherein the first reactive component is
reactive with the second reactive component.
[0228] Aspect 50. The method of aspect 49, wherein each of the
first reactive component and the second reactive component comprise
a monomer, a copolymer, or a combination thereof.
[0229] Aspect 51. The method of any one of aspects 1 to 50, wherein
each of the first composition and the second composition are
curable using actinic radiation.
[0230] Aspect 52. The method of any one of aspects 1 to 51, wherein
the first composition comprises a first viscosity, and the second
composition comprises a second viscosity, wherein the first
viscosity is less than the second viscosity.
[0231] Aspect 53. The method of any one of aspects 1 to 52, wherein
the first composition comprises: a first concentration of a first
component; and the second composition comprises a second
concentration of the first component, wherein the second
concentration is less than the first concentration.
[0232] Aspect 54. The method of any one of aspects 1 to 53, wherein
a portion of the layer has a first volume, and the portion of the
modified layer corresponding to the portion of the layer has a
second volume, wherein the second volume is less than the first
volume.
[0233] Aspect 55. The method of aspect 54, wherein the second
volume is less than 75% of the first volume.
[0234] Aspect 56. The method of aspect 54, wherein the second
volume is less than 50% of the first volume.
[0235] Aspect 57. The method of any one of aspects 1 to 56, wherein
each of the first composition and the second composition comprise
particles.
[0236] Aspect 58. The method of claim 1, wherein the particles
comprise photoactive particles, electroactive particles, or a
combination thereof.
[0237] Aspect 59. The method of any one of aspects 1 to 58, wherein
the first composition comprises a first concentration of particles;
the modified layer comprises a second concentration of particles;
wherein the second concentration is greater than the first
concentration.
[0238] Aspect 60. The method of any one of aspects 1 to 59, wherein
the selectively absorbing film comprises one or more layers wherein
each of the one or more layers independently comprises a polymer of
intrinsic microporosity (PIMs), a porous organic polymer (POP), a
polysiloxanes, a metal organic framework (MOFs), a porous
coordination polymers (PCPs), or a combination of any of the
foregoing.
[0239] Aspect 61. The method of any one of aspects 1 to 60, wherein
the selectively absorbing film comprises a silicone.
[0240] Aspect 62. A modified layer fabricated using the method of
any one of aspects 1 to 61.
[0241] Aspect 63. A cured modified layer prepared by curing the
modified layer of aspect 62.
[0242] Aspect 64. An electronic device comprising the cured
modified layer of aspect 63.
[0243] Aspect 65. The electronic device of aspect 64, wherein the
electronic device comprises an optoelectronic device.
[0244] Aspect 66. The electronic device of aspect 64, wherein the
electronic device comprises a display or a lighting device.
[0245] Aspect 67. An electronic system comprising the electronic
device of any one of aspects 64 to 66.
[0246] Aspect 68. A selectively absorbing film, comprising one or
more absorbing layers.
[0247] Aspect 69. A method of fabricating one or more pixels,
comprising: providing a substrate comprising one or more recesses,
wherein each of the one or more recesses defines a pixel;
depositing a first composition into each of the one or more
recesses, wherein the first composition comprises one or more
components; applying a selectively absorbing film in proximity to
the deposited first composition; and causing one or more components
of the deposited first composition to absorb into the selectively
absorbing film, to provide one or more pixels comprising a modified
first composition.
[0248] Aspect 70. The method of aspect 69, wherein causing produces
a free volume within each of the one or more recesses, and the
method further comprises depositing a second composition into the
free volume within each of the one or more recesses.
[0249] Aspect 71. The method of any one of aspects 69 to 70,
wherein the second composition and the first composition are the
same.
[0250] Aspect 72. The method of any one of aspects 69 to 70,
wherein the second composition and the first composition are
different.
[0251] Aspect 73 The method of any one of aspects 69 to 72, further
comprising: applying a selectively absorbing film in proximity to
the deposited second composition; and causing one or more
components of the deposited second composition to absorb into the
selectively absorbing film.
[0252] Aspect 74. The method of any one of aspects 69 to 73,
wherein the first composition comprises a plurality of
particles.
[0253] Aspect 75. The method of any one of aspects 69 to 74,
wherein the first composition comprises a plurality of quantum
dots.
[0254] Aspect 76. The method of any one of aspects 69 to 75,
wherein, the first composition comprises a first vol % of the
particles; and the modified first composition comprises a second
vol % of particles, wherein the second vol % is greater than the
first vol %, wherein vol % is based on the volume of the first
composition and the volume of the modified composition,
respectively
[0255] Aspect 77. The method of any one of aspects 69 to 76,
wherein, a recess comprising the first composition comprises a
first vol % of the particles; the pixel has a second vol % of the
particles, the second vol % is greater than the first vol %,
wherein vol % is based on the volume of the recess.
[0256] Aspect 78. The method of any one of aspects 69 to 77,
wherein each of the one or more recesses comprises a width from 1
.mu.m to 4 .mu.m and a depth from 1 .mu.m to 4 .mu.m.
[0257] Aspect 79. The method of any one of aspects 69 to 78,
wherein each of the one or more pixels is characterized by a
conversion efficiency from 40% to 80%,
[0258] Aspect 80. A pixel fabricated using the method of any one of
aspects 69 to 79.
[0259] Aspect 81. The pixel of aspect 80, wherein the pixel has a
volume from 1 .mu.m.sup.3 to 30 .mu.m.sup.3, and a quantum
efficiency greater than 75%.
[0260] Aspect 82. The pixel of any one of aspects 80 to 81, wherein
the pixel comprises a plurality of quantum dots.
[0261] Aspect 83. The pixel of any one of aspects 80 to 82, wherein
the pixel comprises from 70 vol % to 90 vol % of the quantum
dots.
[0262] Aspect 84. An electronic device comprising the pixel of any
one of aspects 80 to 83.
[0263] Aspect 85. The electronic device of aspect 84, wherein the
electronic device comprises an optoelectronic device.
[0264] Aspect 86. The electronic device of aspect 84, wherein the
electronic device comprises a display or a lighting device.
[0265] Aspect 87. An electronic system comprising the electronic
device of any one of aspects 84 to 86.
[0266] Aspect 1A. A method of modifying the composition of a layer,
comprising: (a) applying a selectively absorbing film in proximity
to a layer, wherein the layer comprises a first composition,
wherein the first composition comprises particles and at least one
additional component; and (b) modifying the first composition by
causing at the at least one additional component to absorb into the
selectively absorbing film; to provide a modified layer, wherein
the modified layer comprises a second composition comprising
particles.
[0267] Aspect 2A. The method of aspect 1A, wherein modifying
comprises concentrating the particles, removing the at least one
additional component from the first composition, or a combination
thereof.
[0268] Aspect 3A. The method of any one of aspects 1A to 2A,
wherein modifying comprises extracting one or more low molecular
weight components from the first composition.
[0269] Aspect 4A. The method of any one of aspects 1A to 3A,
wherein modifying comprises decreasing a volume of the layer.
[0270] Aspect 5A. The method of any one of aspects 1A to 4A,
wherein modifying comprises concentrating the particles in the
first composition.
[0271] Aspect 6A. The method of any one of aspects 1A to 5A,
wherein modifying comprises removing one or more components from
the first composition.
[0272] Aspect 7A. The method of any one of aspects 1A to 6A,
wherein the first composition comprises a first vol % of the
particles; the second composition comprises a second vol % of the
particles; and the second vol % is greater than the first vol
%.
[0273] Aspect 8A. The method of any one of aspects 1A to 7A,
wherein the particles comprise a photoactive material.
[0274] Aspect 9A. The method of any one of aspects 1A to 8A,
wherein the particles comprise quantum dots.
[0275] Aspect 10A. The method of any one of aspects 1A to 9A,
wherein the layer is disposed within one or more recesses.
[0276] Aspect 11A. The method of any one of aspects 1A to 10A,
wherein the layer is disposed within one or more recesses, wherein
the recesses have a depth from 1 .mu.m to 4 .mu.m and a width from
1 .mu.m to 4 .mu.m.
[0277] Aspect 12A. The method of any one of aspects 1A to 11A,
wherein the first composition comprises: a first concentration of a
first component; and the second composition comprises a second
concentration of the first component, wherein the second
concentration is less than the first concentration.
[0278] Aspect 13A. The method of any one of aspects 1A to 12A,
wherein a portion of the layer has a first volume, and the portion
of the modified layer corresponding to the portion of the layer has
a second volume, wherein the second volume is less than the first
volume.
[0279] Aspect 14A. The method of any one of aspects 1A to 13A,
wherein the first composition comprises a first concentration of
the particles; the modified layer comprises a second concentration
of the particles; wherein the second concentration is greater than
the first concentration.
[0280] Aspect 15A. A modified layer fabricated using the method of
any one of aspects 1A to 14A.
[0281] Aspect 16A. A cured modified layer prepared by curing the
modified layer of aspect 15A.
[0282] Aspect 17A. An electronic device comprising the cured
modified layer of aspect 16A.
[0283] Aspect 18A. A method of fabricating one or more pixels,
comprising: providing a substrate comprising one or more recesses,
wherein each of the one or more recesses defines a pixel;
depositing a first composition into each of the one or more
recesses, wherein the first composition comprises particles and one
or more additional components; applying a selectively absorbing
film in proximity to the deposited first composition; and causing
one or more of the additional components of the deposited first
composition to absorb into the selectively absorbing film, to
provide one or more pixels comprising a modified first
composition.
[0284] Aspect 19A. The method of aspect 18A, wherein, the first
composition comprises a first vol % of the particles; and the
modified first composition comprises a second vol % of particles,
wherein the second vol % is greater than the first vol %, wherein
vol % is based on the volume of the first composition and the
volume of the modified composition, respectively
[0285] Aspect 20A. The method of any one of aspects 18A to 19A,
further comprising: depositing a second composition onto the
modified first composition, wherein the second composition
comprises particles and one or more additional components; applying
a selectively absorbing film in proximity to the deposited second
composition; and causing one or more of the additional components
of the deposited second composition to absorb into the selectively
absorbing film, to provide one or more pixels comprising the
modified first composition and a modified second composition.
[0286] Aspect 21A. The method of any one of aspects 18A to 20A,
wherein the particles comprises a photoactive material.
[0287] Aspect 22A. The method of any one of aspects 18A to 21A,
wherein the particles comprise quantum dots.
[0288] Aspect 23A. A pixel fabricated using the method of any one
of aspects 18A to 22A.
[0289] Aspect 24A. The pixel of aspect 23A, wherein the particles
comprise a plurality of quantum dots.
[0290] Aspect 25A. An electronic device comprising the pixel of any
one of aspects 23A to 24A.
[0291] Finally, it should be noted that there are alternative ways
of implementing the embodiments disclosed herein. Accordingly, the
present embodiments are to be considered as illustrative and not
restrictive. Furthermore, the claims are not to be limited to the
details given herein, and are entitled to their full scope and
equivalents thereof
* * * * *