U.S. patent application number 15/615843 was filed with the patent office on 2017-12-14 for light-emitting material, method for producing light-emitting material and display apparatus.
This patent application is currently assigned to Chi Mei Corporation. The applicant listed for this patent is Chi Mei Corporation. Invention is credited to Yuan-Ren Juang, Jen-Shrong Uen, Szu-Chun Yu.
Application Number | 20170358745 15/615843 |
Document ID | / |
Family ID | 60574153 |
Filed Date | 2017-12-14 |
United States Patent
Application |
20170358745 |
Kind Code |
A1 |
Juang; Yuan-Ren ; et
al. |
December 14, 2017 |
LIGHT-EMITTING MATERIAL, METHOD FOR PRODUCING LIGHT-EMITTING
MATERIAL AND DISPLAY APPARATUS
Abstract
A light-emitting material, a method for producing the
light-emitting material and a display apparatus are provided. An
average particle size of the light-emitting material is 0.1 .mu.m
to 30 .mu.m, and an average distance between outermost quantum dots
of a particle of the light-emitting material and a surface of the
particle of the light-emitting material is 0.5 nm to 25 nm, or a
minimum distance between the outermost quantum dots of a particle
of the light-emitting material and the surface of the particle of
the light-emitting material is 0.1 nm to 20 nm.
Inventors: |
Juang; Yuan-Ren; (Tainan
City, TW) ; Yu; Szu-Chun; (Tainan City, TW) ;
Uen; Jen-Shrong; (Tainan City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chi Mei Corporation |
Tainan City |
|
TW |
|
|
Assignee: |
Chi Mei Corporation
Tainan City
TW
|
Family ID: |
60574153 |
Appl. No.: |
15/615843 |
Filed: |
June 7, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 33/18 20130101;
H01L 33/502 20130101; C09K 11/06 20130101; H01L 51/0001 20130101;
H01L 27/15 20130101; H01L 33/346 20130101; H01L 51/502 20130101;
H01L 33/145 20130101; H01L 51/005 20130101; H01L 51/0081
20130101 |
International
Class: |
H01L 51/00 20060101
H01L051/00; H01L 27/15 20060101 H01L027/15; H01L 33/34 20100101
H01L033/34; H01L 33/14 20100101 H01L033/14; C09K 11/06 20060101
C09K011/06; H01L 33/18 20100101 H01L033/18 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 8, 2016 |
TW |
105118241 |
Claims
1. A light-emitting material, wherein an average particle size of
the light-emitting material is 0.1 .mu.m to 30 .mu.m, and a minimum
distance between outermost quantum dots of a particle of the
light-emitting material and a surface of the particle of the
light-emitting material is 0.1 nm to 20 nm.
2. A light-emitting material, wherein an average particle size of
the light-emitting material is 0.1 .mu.m to 30 .mu.m, and an
average distance between outermost quantum dots of a particle of
the light-emitting material and a surface of the particle of the
light-emitting material is 0.5 nm to 25 nm.
3. The light-emitting material as claimed in claim 1, wherein the
quantum dots are selected from the group consisting of silicon
based nanocrystals, perovskite nanocrystals, II-VI group compound
semiconductor nanocrystals, III-V group compound semiconductor
nanocrystals and IV-VI group compound semiconductor
nanocrystals.
4. The light-emitting material as claimed in claim 2, wherein the
quantum dots are selected from the group consisting of silicon
based nanocrystals, perovskite nanocrystals, II-VI group compound
semiconductor nanocrystals, III-V group compound semiconductor
nanocrystals and IV-VI group compound semiconductor
nanocrystals.
5. The light-emitting material as claimed in claim 1, wherein the
particle comprises: a core; a package layer, wrapping the core; and
the quantum dots, disposed between the core and the package
layer.
6. The light-emitting material as claimed in claim 5, wherein a
material of the core is porous.
7. The light-emitting material as claimed in claim 6, wherein a
surface mean aperture of the core is 3 nm to 100 nm.
8. The light-emitting material as claimed in claim 6, wherein when
the quantum dots are red light quantum dots, a surface mean
aperture of the core is 7 nm to 30 nm, when the quantum dots are
green light quantum dots, a surface mean aperture of the core is 5
nm to 20 nm, and when the quantum dots are blue light quantum dots,
a surface mean aperture of the core is 3 nm to 15 nm.
9. The light-emitting material as claimed in claim 6, wherein a
specific surface area of the core is 100 m.sup.2/g to 1000
m.sup.2/g.
10. The light-emitting material as claimed in claim 5, wherein a
material of the package layer is selected from the group consisting
of polysiloxane, glass, water glass and silicon dioxide.
11. The light-emitting material as claimed in claim 5, wherein a
thickness of the package layer is 0.1 nm to 20 nm.
12. The light-emitting material as claimed in claim 5, wherein an
average particle size of the core is 0.1 .mu.m to 25 .mu.m.
13. The light-emitting material as claimed in claim 5, wherein the
core has lipophilicity.
14. The light-emitting material as claimed in claim 2, wherein the
particle comprises: a core; a package layer, wrapping the core; and
the quantum dots, disposed between the core and the package
layer.
15. The light-emitting material as claimed in claim 14, wherein a
material of the core is porous.
16. The light-emitting material as claimed in claim 15, wherein a
surface mean aperture of the core is 3 nm to 100 nm.
17. The light-emitting material as claimed in claim 15, wherein
when the quantum dots are red light quantum dots, a surface mean
aperture of the core is 7 nm to 30 nm, when the quantum dots are
green light quantum dots, a surface mean aperture of the core is 5
nm to 20 nm, and when the quantum dots are blue light quantum dots,
a surface mean aperture of the core is 3 nm to 15 nm.
18. The light-emitting material as claimed in claim 15, wherein a
specific surface area of the core is 100 m.sup.2/g to 1000
m.sup.2/g.
19. The light-emitting material as claimed in claim 14, wherein a
material of the package layer is selected from the group consisting
of polysiloxane, glass, water glass and silicon dioxide.
20. The light-emitting material as claimed in claim 14, wherein a
thickness of the package layer is 0.1 nm to 20 nm.
21. The light-emitting material as claimed in claim 14, wherein an
average particle size of the core is 0.1 .mu.m to 25 .mu.m.
22. The light-emitting material as claimed in claim 14, wherein the
core has lipophilicity.
23. A display apparatus, comprising: the light-emitting material as
claimed in claim 1, wherein the display apparatus is a television,
a digital camera, a digital video camera, a digital photo frame, a
mobile phone, a notebook computer, a monitor for a computer, an
audio reproduction device, a game machine or a vehicle display.
24. A display apparatus, comprising: the light-emitting material as
claimed in claim 2, wherein the display apparatus is a television,
a digital camera, a digital video camera, a digital photo frame, a
mobile phone, a notebook computer, a monitor for a computer, an
audio reproduction device, a game machine or a vehicle display.
25. A method for producing a light-emitting material, comprising:
producing a core attached with quantum dots; and mixing the core
attached with the quantum dots with a package material to produce
the light-emitting material, wherein a particle of the
light-emitting material comprises the core, the quantum dots and a
package layer, the package layer is composed of the package
material and wraps the core, and the quantum dots are disposed
between the core and the package layer.
26. The method for producing the light-emitting material as claimed
in claim 25, wherein the step of producing the core attached with
the quantum dots comprises producing the core with an average
particle size of 0.1 .mu.m to 25 .mu.m and attached with the
quantum dots.
27. The method for producing the light-emitting material as claimed
in claim 25, wherein the package layer is obtained through a
reaction of silicon oxide.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan
application serial no. 105118241, filed on Jun. 8, 2016. The
entirety of the above-mentioned patent application is hereby
incorporated by reference herein and made a part of this
specification.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The invention relates to a light-emitting material, a method
for producing the light-emitting material and a display apparatus,
and particularly relates to a light-emitting material having
quantum dots, a method for producing the light-emitting material
and a display apparatus.
Description of Related Art
[0003] Quantum dot is a material with good light absorption and
luminescence properties, which has narrow light-emitting full width
at half maximum (FWHM), high light-emitting efficiency and a wider
absorption spectrum, so that it has high color purity and
saturation, and is gradually applied to display panel techniques in
recent years. Presently, when the quantum dots are applied, the
quantum dots are directly dispersed in a solvent, and then coated
on a desired position. However, the light-emitting feature of the
quantum dot has considerable relevance with a size thereof. Not
only the quantum dots are hard to be evenly distributed in the
solvent, but also the quantum dots are probably gathered into
micron-sized quantum dot clusters. In this case, light-emitting
uniformity is not easy to be improved, and the micron-sized quantum
dot clusters may loss the light-emitting feature. On the other
hand, the quantum dots preserved in a liquid form have high
difficulty in application, and are not easy to be applied in
various different processing designs. Moreover, the periphery of
the quantum dots and polymers such as ligands thereof have
disadvantages of none high-temperature endurance, which also limits
the application of the quantum dots. Therefore, how to produce a
quantum dot material with a long service life becomes an important
issue in application and promotion of the quantum dots.
SUMMARY OF THE INVENTION
[0004] The invention is directed to a light-emitting material, a
method for producing the light-emitting material and a display
apparatus, which are adapted to resolve a problem of poor
light-emitting efficiency of quantum dots.
[0005] The invention provides a light-emitting material with an
average particle size of 0.1 .mu.m to 30 .mu.m, where a minimum
distance between outermost quantum dots of a particle of the
light-emitting material and a surface of the particle of the
light-emitting material is 0.1 nm to 20 nm.
[0006] The invention provides another light-emitting material with
an average particle size of 0.1 .mu.m to 30 .mu.m, where an average
distance between outermost quantum dots of a particle of the
light-emitting material and a surface of the particle of the
light-emitting material is 0.5 nm to 25 nm.
[0007] In an embodiment of the invention, the quantum dots are
selected from the group consisting of silicon based nanocrystals,
perovskite nanocrystals, II-VI group compound semiconductor
nanocrystals, III-V group compound semiconductor nanocrystals and
IV-VI group compound semiconductor nanocrystals.
[0008] In an embodiment of the invention, an average particle size
of the quantum dots is 1 nm to 25 nm.
[0009] In an embodiment of the invention, the quantum dots include
red light quantum dots, green light quantum dots and blue light
quantum dots, where an average particle size of the red light
quantum dots is 3 nm to 25 nm, an average particle size of the
green light quantum dots is 2 nm to 20 nm, and an average particle
size of the blue light quantum dots is 1 nm to 15 nm.
[0010] In an embodiment of the invention, under irradiation of a
light with a wavelength of 390 nm to 500 nm, the red light quantum
dots emit a light with a peak wavelength of 610 nm to 660 nm and a
peak full width at half maximum (FWHM) of 15 nm to 60 nm, the green
light quantum dots emit a light with a peak wavelength of 520 nm to
550 nm and a peak FWHM of 15 nm to 60 nm, and the blue light
quantum dots emit a light with a peak wavelength of 440 nm to 460
nm and a peak FWHM of 15 nm to 60 nm.
[0011] In an embodiment of the invention, under irradiation of a
light with a wavelength of 390 nm to 500 nm, the quantum dots emit
a light with a peak wavelength of 400 nm to 700 nm and a peak FWHM
of 15 nm to 60 nm.
[0012] In an embodiment of the invention, a weight percentage of
the quantum dots is 0.1% to 30%.
[0013] In an embodiment of the invention, the particle includes a
core, a package layer and the quantum dots. The package layer wraps
the core, and the quantum dots are disposed between the core and
the package layer.
[0014] In an embodiment of the invention, a material of the core is
porous.
[0015] In an embodiment of the invention, a surface mean aperture
of the core is 3 nm to 100 nm.
[0016] In an embodiment of the invention, when the quantum dots are
the red light quantum dots, the surface mean aperture of the core
is 7 nm to 30 nm, when the quantum dots are the green light quantum
dots, the surface mean aperture of the core is 5 nm to 20 nm, and
when the quantum dots are the blue light quantum dots, the surface
mean aperture of the core is 3 nm to 15 nm.
[0017] In an embodiment of the invention, a specific surface area
of the core is 100 m.sup.2/g to 1000 m.sup.2/g.
[0018] In an embodiment of the invention, a material of the core is
selected from the group consisting of polysiloxane, glass, water
glass and silicon dioxide.
[0019] In an embodiment of the invention, a material of the package
layer is selected from the group consisting of polysiloxane, glass,
water glass and silicon dioxide.
[0020] In an embodiment of the invention, a thickness of the
package layer is 0.1 nm to 20 nm.
[0021] In an embodiment of the invention, an average particle size
of the core is 0.1 .mu.m to 25 .mu.m.
[0022] In an embodiment of the invention, the core has
lipophilicity.
[0023] The invention provides a method for producing a
light-emitting material, which includes following steps. A core
attached with quantum dots is produced. The core attached with the
quantum dots and a package material are mixed to produce the
light-emitting material. A particle of the light-emitting material
includes the core, the quantum dots and a package layer, where the
package layer is composed of the package material and wraps the
core, and the quantum dots are disposed between the core and the
package layer.
[0024] In an embodiment of the invention, the step of producing the
core attached with the quantum dots includes producing the core
with an average particle size of 0.1 .mu.m to 25 .mu.m and attached
with the quantum dots.
[0025] In an embodiment of the invention, the step of producing the
core attached with the quantum dots includes mixing a quantum dot
solution with the core, where the quantum dot solution is formed by
mixing the quantum dots with n-hexane.
[0026] In an embodiment of the invention, a weight percentage of
the quantum dots of the quantum dot solution is 0.1% to 5%.
[0027] In an embodiment of the invention, the step of producing the
core attached with the quantum dots includes mixing the quantum
dots with a core solution, where the core solution is formed by
mixing the core with n-hexane.
[0028] In an embodiment of the invention, a weight percentage of
the core of the core solution is 0.5% to 10%.
[0029] In an embodiment of the invention, the step of producing the
core attached with the quantum dots includes centrifugal filtration
after standing.
[0030] In an embodiment of the invention, the package layer is
obtained through the reaction of silicon oxide.
[0031] The invention provides a display apparatus including the
aforementioned light-emitting material, and the display apparatus
is a television, a digital camera, a digital video camera, a
digital photo frame, a mobile phone, a notebook computer, a monitor
for a computer, an audio reproduction device, a game machine or a
vehicle display.
[0032] According to the above description, in the light-emitting
material, the method for producing the light-emitting material and
the display apparatus, the quantum dots are located in internal of
the light-emitting material and the light-emitting material
presents a granular state, so that during the application, the
quantum dots are unnecessary to be distributed in the solvent and
are not gathered to lose the light-emitting feature, such that good
light-emitting efficiency is achieved.
[0033] In order to make the aforementioned features and advantages
of the invention comprehensible, several exemplary embodiments
accompanied with figures are described in detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
[0035] FIG. 1 is a cross-sectional view of a light-emitting
material according to an embodiment of the invention.
[0036] FIG. 2 is a flowchart illustrating a method for producing a
light-emitting material according to an embodiment of the
invention.
[0037] FIG. 3 and FIG. 4 are pictures of the light-emitting
material after embedding and sectioning observed through a
transmission electron microscopy.
[0038] FIG. 5A to FIG. 5J are schematic diagrams of display
apparatuses according to a plurality of embodiments of the
invention.
DESCRIPTION OF EMBODIMENTS
[0039] FIG. 1 is a cross-sectional view of a light-emitting
material according to an embodiment of the invention. Referring to
FIG. 1, an average particle size of the light-emitting material 100
of the present embodiment is 0.1 .mu.m to 30 .mu.m, or 0.5 .mu.m to
25 .mu.m, or 0.5 .mu.m to 20 .mu.m. From a macro point of view, the
light-emitting material 100 of the present embodiment presents a
granular state, and a size of each particle is probably different,
though the particle size of the light-emitting material of the
present embodiment is 0.1 .mu.m to 30 .mu.m, or within the
aforementioned ranges. The average particle size of the
light-emitting material 100 is an average of the particle sizes of
at least 20 particles in the light-emitting material 100. Regarding
a distance between outermost quantum dots 110 of the particle of
the light-emitting material 100 and a surface S10 of the particle
of the light-emitting material 100, two aspects are provided for
description, and there is no interdependence between the two
aspects, and any light-emitting material complying with any one of
the two aspects is considered to be the light-emitting material
suitable for the invention.
[0040] One of the aspects is to discuss a minimum distance D10
between the outermost quantum dots 110 of the particle of the
light-emitting material 100 and the surface S10 of the particle of
the light-emitting material 100, and a range of the minimum
distance D10 is 0.1 nm to 20 nm, i.e. the minimum distance D10
between the quantum dots 110 located the closest to the particle
surface in the particle and the particle surface S10 of the
light-emitting material 100 is 0.1 nm to 20 nm, or 0.1 nm to 15 nm,
or 0.1 nm to 10 nm.
[0041] The other aspect is to discuss an average distance between
the outermost quantum dots 110 of the particle of the
light-emitting material 100 and the surface S10 of the particle of
the light-emitting material 100, and a range of the average
distance is 0.5 nm to 25 nm, or 0.5 nm to 18 nm, or 0.5 nm to 12
nm. The calculation method of the average distance is, for example,
to adopt at least three particles in the light-emitting material
100 to obtain the minimum distance D10 between the outermost
quantum dot 110 of each of the three particles and the surface S10
of the particle, and take an average of the at least three minimum
distances D10 as the average distance.
[0042] Since the particle size of the light-emitting material 100
of the present embodiment is 0.1 .mu.m to 30 .mu.m, which is
greater than the nanometre-level size of the quantum dot itself,
the light-emitting material 100 can be used in form of a solid
state, or can be added into a solvent and used in form of a liquid
state, and uniformity of distribution of the light-emitting
material 100 with the particle size of 0.1 .mu.m to 30 .mu.m can be
easily controlled in usage. The particle size of the light-emitting
material 100 can be observed and measured by using a transmission
electron microscopy. Moreover, since the minimum distance D10
between the outermost quantum dots 110 of the light-emitting
material 100 and the surface S10 of the particle of the
light-emitting material 100 is 0.1 nm to 20 nm, or the average
distance between the outermost quantum dots 110 of the
light-emitting material 100 and the surface S10 of the particle of
the light-emitting material 100 is 0.5 nm to 25 nm, the quantum
dots 110 can be properly protected, and when the light-emitting
material 100 is applied to a light-emitting diode (LED) package or
other products, the quantum dots 110 embedded in the light-emitting
material 100 can be properly protected, and may resist a chemical
reaction and high temperature, high humidity in a processing
process, such that reliability of a final product is improved and
better light-emitting efficiency is maintained. If the quantum dots
110 are excessively close to the surface S10 in the light-emitting
material 100, the quantum dots 110 probably cannot be sufficiently
protected, and the final light-emitting efficiency is influenced by
a process environment. If the quantum dots 110 are located
excessively away from the surface S10 in the light-emitting
material 100, it may have a problem of insufficient overall
light-emitting efficiency. Moreover, through the porous cores, so
that there is appropriate distances between the quantum dots 110,
and avoid excessive close distances between the quantum dots 110 to
lose the light-emitting feature.
[0043] The quantum dots 110 of the present embodiment are, for
example, selected from the group consisting of silicon based
nanocrystals, perovskite nanocrystals, II-VI group compound
semiconductor nanocrystals, III-V group compound semiconductor
nanocrystals and IV-VI group compound semiconductor nanocrystals,
though the invention is not limited thereto.
[0044] One of implementations of the aforementioned perovskite
nanocrystal is organic metal halide RNH.sub.3PbX.sub.3 or pure
inorganic perovskite CsPbX.sub.3, where R can be C.sub.nH.sub.2n+1,
n has a range of 1-10, and X is selected from the group consisting
of chlorine, bromine and iodine or a mixture thereof; for example,
selected from the group consisting of CH.sub.3NH.sub.3PbI.sub.3,
CH.sub.3NH.sub.3PbCl.sub.3, CH.sub.3NH.sub.3PbBr.sub.3,
CH.sub.3NH.sub.3PbI.sub.2Cl, CH.sub.3NH.sub.3PbICl.sub.2,
CH.sub.3NH.sub.3PbI.sub.2Br, CH.sub.3NH.sub.3PbIBr.sub.2,
CH.sub.3NH.sub.3PbIClBr, CsPbI.sub.3, CsPbCl.sub.3, CsPbBr.sub.3,
CsPbI.sub.2Cl, CsPbICl.sub.2, CsPbI.sub.2Br, CsPbIBr.sub.2 and
CsPbIClBr, though the invention is not limited thereto.
[0045] One of implementations of the aforementioned II-VI group
compound semiconductor nanocrystal is II-VI, where II is selected
from the group consisting of zinc, cadmium and mercury or a mixture
thereof, VI is selected from the group consisting of oxygen,
sulfur, selenium, tellurium or a mixture thereof; for example,
selected from the group consisting of CdO, CdS, CdSe, CdTe, ZnO,
ZnS, ZnSe, ZnTe, HgO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS,
ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS,
CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe,
CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe and HgZnSTe, though
the invention is not limited thereto. One of implementations of the
aforementioned III-V group compound semiconductor nanocrystal is
III-V, where III is selected from the group consisting of
aluminium, gallium and indium or a mixture thereof, V is selected
from the group consisting of nitrogen, phosphorus, arsenic or a
mixture thereof; for example, selected from the group consisting of
GaN, GaP, GaAs, AlN, AlP, AlAs, InN, InP, InAs, GaNP, GaNAs, GaPAs,
AlNP, AlNAs, AlPAs, InNP, InNAs, InPAs, GaAlNP, GaAlNAs, GaAlPAs,
GaInNP, GaInNAs, GaInPAs, InAlNP, InAlNAs, InCuSe and InAlPAs,
though the invention is not limited thereto. The aforementioned
IV-VI group compound semiconductor nanocrystal is, for example,
PbTe, though the invention is not limited thereto.
[0046] Moreover, those skilled in the art should understand that
the quantum dots 110 of the nano-particle type can be divided into
a binary core, a ternary core or a quaternary core structure.
Alternatively, the quantum dots 110 of the nano-particle type can
be a core-shell structure or a core-multi-shell structure.
Alternatively, the quantum dots 110 of the nano-particle type can
be doped or graded nano-particles. The quantum dots 110 of the
present embodiment are preferably nano-particles of a CdSe/ZnS
core/shell structure.
[0047] The inorganic surface atoms of the quantum dots 110 may
implement surface reforming by using an organic group. The organic
group avails suppressing gathering of the quantum dots, and may
properly isolate the quantum dots 110 from their surrounding
electronic and chemical environments. The organic group is
generally referred to as a sealing agent. In many cases, the
sealing agent includes or is basically formed by a Lewis base
compound, for example, a hydrocarbon Lewis base compound diluted in
an inert solvent. The sealing agent includes mono-functional or
multifunctional ligands, for example, phosphine (trioctylphosphine,
triphenylphosphine, t-butylphosphine etc.), phosphine oxide
(trioctylphosphine oxide, triphenylphosphine oxide, etc.), alkyl
phosphonic acid, alkylamine (hexadecylamine, octylamine, etc.),
arylamine, pyridine, long chain fatty acid, thiophene, etc.
[0048] A change of the average particle size of the quantum dots
may cause a change of a wavelength of a light emitted by the
quantum dots. Therefore, a peak wavelength of the light emitted by
the quantum dots can be controlled by the material and the size of
the quantum dots. The average particle size of the quantum dots 110
of the present embodiment is, for example, 1 nm to 25 nm, or 1 nm
to 15 nm, or 1 nm to 10 nm. The quantum dots 110 of the present
embodiment include red light quantum dots, green light quantum dots
and blue light quantum dots. The red light quantum dots are
configured to emit a red light, and an average particle size
thereof is, for example, 3 nm to 25 nm, or 4 nm to 15 nm, or 5 nm
to 10 nm. The green light quantum dots are configured to emit a
green light, and an average particle size thereof is, for example,
2 nm to 20 nm, or 3 nm to 15 nm, or 4 nm to 9 nm. The blue light
quantum dots are configured to emit a blue light, and an average
particle size thereof is, for example, 1 nm to 15 nm, or 2 nm to 10
nm, or 2 nm to 8 nm.
[0049] A photoluminescence (PL) analysis may quickly and reliably
measure an energy level structure and a transition behaviour in the
material, which is a powerful and non-destructive analysis
technique. By analyzing features of an excitation spectrum, a type
of doped impurity, a band gap size, a compound composition of the
material can be learned, or important information such as a quantum
dot size, a carrier transmission path and a service life, etc. of
the material can be learned. Regarding the quantum dot material,
the photoluminescence analysis may measure a quantum dot shape, a
quantum dot size, an optical energy value of electrons in energy
level transition, various reliabilities, etc., so that the
photoluminescence analysis can be used as an evaluation tool for
quantum dots.
[0050] Regardless of an excitation source, once the electrons of
the excited atoms are excited, the electrons may release an energy
difference between the energy levels in form of lighting when the
electrons fall from a high energy excitation state to a low energy
ground state. When an emission spectrum of the quantum dot is
analyzed, following parameters are noted: (1) a wavelength and a
strength thereof corresponding to a peak of an emission spectrum;
(2) a wavelength corresponding to two sides of a half peak width;
(3) full width at half maximum (FWHM).
[0051] In an embodiment of the invention, when the light-emitting
material 100 is irradiated by a light with a wavelength greater
than 350 nm and smaller than a light-emitting wavelength, for
example, a light with a wavelength of 390 nm to 500 nm, the light
emitting material 100, for example, emits a light with a peak
wavelength of 400 nm to 700 nm, and the FWHM of the light is for
example, 15 nm to 60 nm or 20 nm to 60 nm.
[0052] In an embodiment of the invention, when the light-emitting
material 100 is irradiated by a light with a wavelength greater
than 350 nm and smaller than a light-emitting wavelength, for
example, a light with a wavelength of 390 nm to 500 nm, the quantum
dots 110, for example, emit a light with a peak wavelength of 400
nm to 700 nm, and the FWHM of the light is for example, 15 nm to 60
nm or 20 nm to 60 nm. In an embodiment of the invention, a peak
wavelength of the light emitted by the red light quantum dots is,
for example, 600 nm to 700 nm, or 605 nm to 680 nm, or 610 nm to
660 nm, and the FWHM of the light is for example, 15 nm to 60 nm or
20 nm to 60 nm. In an embodiment of the invention, a peak
wavelength of the light emitted by the green light quantum dots is,
for example, 500 nm to 600 nm, or 510 nm to 560 nm, or 520 nm to
550 nm, and the FWHM of the light is for example, 15 nm to 60 nm or
20 nm to 60 nm. In an embodiment of the invention, a peak
wavelength of the light emitted by the blue light quantum dots is,
for example, 400 nm to 500 nm, or 430 nm to 470 nm, or 440 nm to
460 nm, and the FWHM of the light is for example, 15 nm to 60 nm or
20 nm to 60 nm. The peak wavelength, the intensity and the FWHM of
the light emitted by the quantum dots are, for example, obtained by
a steady state fluorescence spectrometer (model No. FLmax-3)
manufactured by Horiba company by performing the photoluminescence
analysis.
[0053] In an embodiment of the invention, a weight percentage of
the quantum dots 110 in the light-emitting material can be 0.1% to
30%. The light-emitting material 100 formed based on the weight
percentage of such range has a stable light-emitting effect. The
weight percentage of the quantum dots 110 in the light-emitting
material refers to a percentage of a weight of the quantum dots 110
relative to a weight of the entire light-emitting material 100.
Moreover, the weight percentage of the quantum dots 110 can also be
0.2% to 25%, or 0.3% to 20%. When the weight percentage of the
quantum dots 110 is lower than 0.1%, a concentration of the quantum
dots 110 in the light-emitting material 100 is relatively low, and
the whole light-emitting efficiency is not good. When the weight
percentage of the quantum dots 110 is higher than 30%, the quantum
dots 110 may have a phenomenon of self absorption, such that the
whole light-emitting efficiency is decreased, and the emitted light
may have a red shift. The weight percentage can be obtained by
means of necessary analysis, for example, an inductively coupled
plasma (ICP) spectrum analysis method, etc.
[0054] Referring to FIG. 1, each particle of the light-emitting
material 100 of the present embodiment includes a core 120, a
package layer 130 and quantum dots 110. The package layer 130 wraps
the core 120. The quantum dots 110 are disposed between the core
120 and the package layer 130. In other words, a thickness D20 of
the package layer 130 substantially determines the minimum distance
D10 between the outermost quantum dots 110 of the particle and the
surface S10 of the particle. The thickness D20 of the package layer
130 is, for example, 0.1 nm to 20 nm.
[0055] A material of the core 120 of the present embodiment can be
material selected from the group consisting of organic polymers,
inorganic polymers, water-soluble polymers, organic solvent-soluble
polymers, biopolymers and synthetic polymers, for example, selected
from the group consisting of polysiloxane, silica, polyacrylate,
polycarbonate, polystyrene, polyethylene, polypropylene,
polyketone, polyether ether ketone, polyester, polyamide,
polyimide, polyacrylamide, polyolefin, polyacetylene, polyisoprene,
polybutadiene, poly(vinylidene fluoride), poly(vinyl chloride),
ethylene vinyl acetate, polyethylene terephthalate, polyurethane
and cellulose polymer. The material of the core 120 of the present
embodiment can also be an inorganic medium, for example, material
selected from the group consisting of silica, bentonite, glass,
quartz, kaolin, silicon dioxide, aluminium oxide and zinc oxide.
The package layer 130 of the present may have a material the same
or different to that of the core 120. The material of the core 120
of the present embodiment is preferably silicon oxide, for example,
material selected from the group consisting of polysiloxane, glass,
water glass and silicon dioxide.
[0056] The material of the package layer 130 of the present
embodiment can be material selected from the group consisting of
organic polymers, inorganic polymers, water-soluble polymers,
organic solvent-soluble polymers, biopolymers and synthetic
polymers, for example, selected from the group consisting of
polysiloxane, silica, polyacrylate, polycarbonate, polystyrene,
polyethylene, polypropylene, polyketone, polyether ether ketone,
polyester, polyamide, polyimide, polyacrylamide, polyolefin,
polyacetylene, polyisoprene, polybutadiene, poly(vinylidene
fluoride), poly(vinyl chloride), ethylene vinyl acetate,
polyethylene terephthalate, polyurethane and cellulose polymer. The
material of the package layer 130 of the present embodiment can
also be an inorganic medium, for example, material selected from
the group consisting of silica, bentonite, glass, quartz, kaolin,
silicon dioxide, aluminium oxide and zinc oxide. The material of
the package layer 130 of the present embodiment is preferably
silicon oxide, for example, material selected from the group
consisting of polysiloxane, glass, water glass and silicon
dioxide.
[0057] The water glass is a material combined with alkali metal
oxide and silicon dioxide, and can be divided into lithium water
glass, sodium silicate and potassium water glass according to the
types of the alkali metal, and molecular formulas thereof are
respectively Li.sub.2O.nSiO.sub.2, Na.sub.2O.nSiO.sub.2 and
K.sub.2P.nSiO.sub.2, in which a coefficient n is referred to as a
water glass modulus, which is a molecular ratio (or mole ratio)
between the silicon oxide and the alkali metal oxide in the water
glass, where n is between 1.5-4.0, and is preferably between
2.0-3.5. The water glass of the present embodiment can be at least
one selected from the group consisting of the lithium water glass,
sodium silicate and potassium water glass, though the invention is
not limited thereto. In the present embodiment, the water glass is
preferably the potassium water glass.
[0058] Polysiloxane is obtained through a hydrolysis and
condensation reaction occurred by adding water to a siloxane
compound shown in a following equation (I):
R.sup.a.sub.nSi(OR.sup.b).sub.4-n n=0.about.3 Equation (I);
[0059] Where, R.sup.a represents an aromatic base with a carbon
number of 6-15, R.sup.b represents an alkyl group with a carbon
number of 1-5. In the present embodiment, the siloxane compound
includes, in a definition of R.sup.a, the aromatic base is, but not
limited to, phenyl, tolyl, p-hydroxyphenyl,
1-(p-hydroxyphenyl)ethyl, 2-(p-hydroxyphenyl)ethyl,
4-hydroxyl-5-(p-hydroxyphenylcarbonyloxy)pentyl or naphthyl. In the
definition of R, the alkyl is, but not limited to, methyl, ethyl,
n-propyl, isopropyl or n-butyl. In the present embodiment, the
polysiloxane is preferably obtained through the hydrolysis and
condensation reaction occurred by adding water to
tetraethoxysilane.
[0060] An average particle size of the core 120 of the present
embodiment is, for example, 0.1 .mu.m to 25 .mu.m, or 0.3 .mu.m to
15 .mu.m, or 0.5 .mu.m to 10 .mu.m. The material of the core 120 of
the present embodiment is porous, and a surface mean aperture of
the core 120 is 3 nm to 100 nm. When the core 120 is porous, it
avails evenly and stably absorbing the quantum dots 110 on the core
120. In an embodiment, when the quantum dots 110 are the red light
quantum dots, the surface mean aperture of the core 120 is, for
example, 7 nm to 40 nm, or 7 nm to 35 nm, or 7 nm to 30 nm. When
the quantum dots 110 are the green light quantum dots, the surface
mean aperture of the core 120 is, for example, 5 nm to 30 nm, or 5
nm to 25 nm, or 5 nm to 20 nm. When the quantum dots 110 are the
blue light quantum dots, the surface mean aperture of the core 120
is, for example, 3 nm to 25 nm, or 3 nm to 20 nm, or 3 nm to 15 nm.
The specific surface area of the core 120 is, for example, 100
m.sup.2/g to 1000 m.sup.2/g. In an embodiment of the invention,
porous micron particles are taken as the cores of the invention.
The porous micron particles can be silicon dioxide particles. The
core may have a property of lipophilicity, and the porous micron
particles can be lipophilic silicon dioxide particles. The
lipophilic cores can be obtained by reforming the core of the
lipophilic silicon dioxide particles through a silane compound
shown in a following equation (II):
R.sup.c.sub.mSi(OR.sup.d).sub.4-m m=1.about.3 Equation (II);
[0061] Where R.sup.c represents an alkyl group with a carbon number
of 3-20, and R.sup.d represents an alkyl group with a carbon number
of 1-15. In the present embodiment, RE is, for example, but not
limited to, octyl, nonyl, or decyl; and R.sup.d is, for example,
but not limited to, methyl, ethyl, n-propyl, isopropyl or
n-butyl.
[0062] Taking the porous core 120 made of silicon dioxide as an
example, it can be a porous core with an average particle diameter
of 1-5 .mu.m, a surface mean aperture of 5-15 nm, and a specific
surface area of 500-900 m.sup.2/g; or the core 120 can be a porous
core with the average particle diameter of 1-5 .mu.m, the surface
mean aperture of 10-30 nm, and the specific surface area of 250-750
m.sup.2/g; or the core 120 can be a porous core with the average
particle diameter of 0.5-1.5 .mu.m, the surface mean aperture of
5-15 nm, and the specific surface area of 200-600 m.sup.2/g; or the
core 120 can be a porous core with the average particle diameter of
0.1-0.5 .mu.m, the surface mean aperture of 3-12 nm, and the
specific surface area of 100-500 m.sup.2/g.
[0063] In the present embodiment, after a high temperature test of
250.degree. C. is performed to the light-emitting material of the
invention for 2 hours, a retention ratio of a photoluminescence
(PL) measurement intensity is 50-75% relative to the PL measurement
intensity before the high temperature test. On the other hand, a
retention ratio of light-emitting efficiency of the conventional
unprocessed (core adsorption, package) quantum dot material after
the same high temperature test is only 2%. Therefore, the structure
of the light-emitting material of the invention avails improving
high temperature resistance capability of the quantum dots.
[0064] According to the above description, it is known that the
light-emitting material of the present embodiment includes the
quantum dots incorporated into an optical transparent medium (for
example, silicon dioxide). The light-emitting material can be
applied to a light-emitting diode (LED) package material (for
example, epoxy resin, polysiloxane resin, acrylate resin, glass,
etc.). The quantum dots in the optical transparent medium are
optically connected to a solid state/primary light source (for
example, a LED, a laser light source, an arc light and a blackbody
light source, etc.), such that when the light-emitting material is
excited by the light coming from the primary light source, the
quantum dots in the light-emitting material may emit a secondary
light with a desired color. Moreover, a required intensity and
wavelength of the light emitted by the whole device can be
satisfied by properly mixing the color of the primary light and the
color of the secondary light produced by the quantum dots through
frequency down-conversion of the primary light. Moreover, a size, a
shape and a composition of the optical transparent medium can be
controller, or the size and the number of the quantum dots of each
type in the optical transparent medium can be controlled to make
the light emitted by the light-emitting material containing the
quantum dots to produce a light with any specific color and
intensity after subsequent light mixing. The LEDs using of the
light-emitting material of the present embodiment may serve as a
backlight unit or a light-emitting assembly of other light-emitting
device, or a plurality of LEDs are arranged in an array to serve as
a quantum dot LED (QLED) display equipment, i.e. each of the LEDs
is a pixel.
[0065] The light-emitting material of the invention can be applied
to various display apparatuses. The display apparatus can be a
television (which is also referred to as a TV, or a TV receiver)
(referring to FIG. 5A), a digital camera (referring to FIG. 5B), a
digital video camera (referring to FIG. 5C), a digital photo frame
(referring to FIG. 5D), a mobile phone (referring to FIG. 5E), a
notebook computer (referring to FIG. 5F), a mobile computer, a
monitor adapted to a computer, etc. (referring to FIG. 5G), a
portable game machine, a portable information terminal, an audio
reproduction device (referring to FIG. 5H), a game machine
(referring to FIG. 5I) and a vehicle display (referring to FIG.
5J).
[0066] It should be noted that the light-emitting material of the
invention is not limited to be applied to the LED package material,
but can also be applied to an optical film, an optical plate, a
transparent tube, an optical component, a backlight unit, a
light-emitting device, a color conversion material, an optical
material, an ink, a label agent, etc., and all of the light emitted
therefrom can be effectively consisted of only the light emitted by
the quantum dots (i.e. only the secondary light), or consisted of
the light emitted by the quantum dots and the light emitted by the
solid state/primary light source (i.e. the primary light and the
secondary light). In an embodiment, the light-emitting material may
contain one or a plurality of types of the quantum dots used for
emitting lights of different colors.
[0067] FIG. 2 is a flowchart illustrating a method for producing
the light-emitting material according to an embodiment of the
invention. Referring to FIG. 2, the method for producing the
light-emitting material of the present embodiment includes
following steps. In step S10, a quantum dot solution and a core
solution are mixed to produce cores attached with the quantum dots.
In step S120, the core attached with the quantum dots and a package
material are mixed in a solvent to produce the light-emitting
material. Each particle of the light-emitting material produced
according to the aforementioned method is substantially the same
with the particle of the light-emitting material of FIG. 1.
[0068] To be specific, in the step S110, the solution evenly
distributed with the quantum dots and the solution evenly
distributed with the cores are mixed to form the cores attached
with the quantum dots. In the step S120, the cores attached with
the quantum dots that are obtained in the aforementioned step and
the package material are mixed in the solvent, such that a package
layer formed by the package material wraps the cores attached with
the quantum dots through a physical and/or chemical change. By
properly adjusting a proportion of the cores and the quantum dots,
and through a combination of physical and chemical features of a
solution system (for example a proportion, a temperature change, a
material feature and a solvent selection), the quantum dots can be
evenly and effectively adsorbed on the cores. Similarly, by
properly adjusting a proportion of the core attached with the
quantum dots and the package material, and through a combination of
physical and chemical features of a solution system (for example, a
proportion, a temperature change, a material feature and a solvent
selection), the quantum dots can be nicely protected by the package
layer.
[0069] The quantum dot solution in the step S110 of the present
embodiment is a solution formed by mixing the quantum dots with
n-hexane. A weight percentage of the quantum dots in the quantum
dot solution is 0.1% to 5%. The core solution in the step S110 of
the present embodiment is a solution formed by mixing the cores
with the n-hexane. A weight percentage of the cores in the core
solution is 0.5% to 10%. In the step S110 of the present
embodiment, the step of producing the core attached with the
quantum dots includes centrifugal filtration after standing. In the
step S120 of the present embodiment, the step of mixing the cores
attached with the quantum dots and the package material in the
solvent to produce the light-emitting material includes: adding
tetraethoxysilane and NH.sub.4OH to the ethanol added with the
cores attached with the quantum dots, and sequentially performing
centrifugal separation, cleaning, centrifugal separation and drying
after stirring the solution at a room temperature.
Quantum Dot Solution Synthesis Example 1
[0070] Cadmium oxide (CdO) of 340 mg and oleic acid of 4500 mg are
added in a three-necked flask. Then, octadecene (ODE) of 15 ml is
added, and the solution is heated and reacted to mix in a vacuum
environment under a temperature of 180.degree. C. Then, nitrogen is
filled in the three-necked flask, and the temperature is elevated
to 250.degree. C. Then, TOPSe of 0.3 ml, 0.2 mmol is injected and
the solution is heated under the temperature of 250.degree. C.
Then, the solution is stirred to produce an orange suspension
liquid, and then the suspension liquid is cooled down and the
reactant is washed by using methanol. Finally, acetone is used to
precipitate and separate a suspended substance, and dissolve the
same in n-hexane, such that an n-hexane solution with a material of
CdSe nanocompound is obtained. Then, trioctylphosphine (TOP) of
1600 mg and sulphur (S) of 64 mg are added to the three-necked
flask, and zinc acetate (ZnAc) of 300 ml is added therein, and the
solution is heated and reacted to mix in a vacuum environment under
a temperature of 120.degree. C. Then, CdSe nanoparticles of 80 mg
are added to react under the temperature of 120.degree. C. Then, a
mixture obtained after the above reaction is cooled down to
60.degree. C., and ethanol of 300 ml is adopted for precipitation.
The obtained precipitate is red quantum dots after centrifugal
separation, and a peak wavelength of the emitted light is 630 nm,
and the FWHM thereof is 30 nm.
Quantum Dot Solution Synthesis Example 2
[0071] CdO of 260 mg, zinc acetate of 7020 mg, and oleic acid of 45
mg are added in a three-necked flask. Then, ODE of 140 ml is added,
and the solution is heated and reacted to mix in the vacuum
environment under a temperature of 120.degree. C. Then, nitrogen is
filled in the three-necked flask, and the temperature is elevated
to 250.degree. C. Then, TOPSe of 20 ml, 0.025 mmol and sulphur of
1080 mg are injected and the solution is heated under the
temperature of 250.degree. C. Then, the solution is stirred to
produce a yellow green suspension liquid, and then the suspension
liquid is cooled down and ethanol of 300 ml is adopted for
precipitation. The obtained precipitate is green quantum dots after
centrifugal separation, and a peak wavelength of the emitted light
is 530 nm, and the FWHM thereof is 40 nm.
[0072] Producing of the Quantum Dot Solution
[0073] The red quantum dots of the quantum dot solution synthesis
example 1 removed with the solvent are mixed with the n-hexane to
produce a red quantum dot n-hexane solution with a weight
percentage of the quantum dots of 1%, so as to obtain a quantum dot
solution (1).
[0074] The green quantum dots of the quantum dot solution synthesis
example 2 removed with the solvent are mixed with the n-hexane to
produce a green quantum dot n-hexane solution with a weight
percentage of the quantum dots of 1%, so as to obtain a quantum dot
solution (2).
[0075] Producing of the Core Solution
[0076] The porous micron particles that take lipophilic silicon
dioxide particles with an average diameter of 3 .mu.m, a surface
mean aperture of 10 nm, and a specific surface area of 700
m.sup.2/g as cores are mixed with n-hexane to produce a porous
micron particle n-hexane solution with a weight percentage of the
porous micron particles of 5%, so as to obtain a core solution
(3).
[0077] The porous micron particles that take lipophilic silicon
dioxide particles with the average diameter of 1 .mu.m, the surface
mean aperture of 10 nm, and the specific surface area of 400
m.sup.2/g as cores are mixed with n-hexane to produce a porous
micron particle n-hexane solution with a weight percentage of the
porous micron particles of 5%, so as to obtain a core solution
(4).
[0078] The porous micron particles that take lipophilic silicon
dioxide particles with the average diameter of 3 .mu.m, the surface
mean aperture of 16 nm, and the specific surface area of 500
m.sup.2/g as cores are mixed with n-hexane to produce a porous
micron particle n-hexane solution with a weight percentage of the
porous micron particles of 5%, so as to obtain a core solution
(5).
[0079] The porous micron particles that take lipophilic silicon
dioxide particles with the average diameter of 0.15 .mu.m, the
surface mean aperture of 5 nm, and the specific surface area of 120
m.sup.2/g as cores are mixed with n-hexane to produce a porous
micron particle n-hexane solution with a weight percentage of the
porous micron particles of 5%, so as to obtain a core solution
(6).
[0080] The porous micron particles that take lipophilic silicon
dioxide particles with the average diameter of 50 .mu.m, the
surface mean aperture of 12 nm, and the specific surface area of
120 m.sup.2/g as cores are mixed with n-hexane to produce a porous
micron particle n-hexane solution with a weight percentage of the
porous micron particles of 5%, so as to obtain a core solution
(7).
[0081] The micron particles that take lipophilic silicon dioxide
particles with the average diameter of 3 .mu.m and non-micropore as
cores are mixed with n-hexane to produce a micron particle n-hexane
solution with a weight percentage of the micron particles of 5%, so
as to obtain a core solution (8).
Embodiment 1
[0082] The aforementioned quantum dot solution (1) of 0.25 g and
the aforementioned core solution (3) of 5 g are mixed, and the
mixture is made to stand for 10 minutes. Then, porous micron
particles containing the quantum dots (i.e. the cores attached with
the quantum dots) are obtained after centrifugal filtration. Then,
the porous micron particles containing the quantum dots are added
to ethanol of 250 g and are evenly dispersed. Then,
tetraethoxysilane (TEOS) of 0.5 g and NH.sub.4OH with a weight
percentage of 29% of 2.5 g are added, and the solution is stirred
for 4 hours at the room temperature, and now a pH value thereof is
10-11. Then, centrifugal separation is performed, and then the
leftover is cleaned by pure water for three times, and then a
drying process is performed to obtain the micron level
light-emitting material of 0.2778 g. After embedding and
sectioning, the light-emitting material can be observed and
measured (shown in FIG. 3 and FIG. 4) by using a transmission
electron microscopy. Moreover, photoluminescence analysis can be
adopted to measure an intensity of a peak of the light-emitting
material, and a result thereof is shown in a table 2.
Embodiments 2-7
[0083] The embodiments 2-7 are the same to the embodiment 1, and
material usage amounts and stir time can be obtained by referring
the table 1.
Embodiments 8
[0084] Referring to the table 1 for the material usage amounts and
the stir time, and except that a tetraethoxysilane package step is
performed twice, the other steps of the embodiment 8 are the same
to the embodiment 1. In detail, the porous micron particles
containing the quantum dots are added to ethanol of 250 g and are
evenly dispersed. Then, TEOS of 2.5 g and NH.sub.4OH with a weight
percentage of 29% of 2.5 g are added, and the solution is stirred
for 8 hours at the room temperature, and now a pH value thereof is
10-11. Then, centrifugal separation is performed, and the leftover
is added to ethanol of 250 g and is evenly dispersed, and TEOS of
2.5 g and NH.sub.4OH with the weight percentage of 29% of 2.5 g are
added, and the solution is stirred for 8 hours at the room
temperature, and is then cleaned by pure water for three times, and
then a drying process is performed to obtain the micron level
light-emitting material of 0.6757 g.
Embodiments 9-13
[0085] The embodiments 6-13 are the same to the embodiment 1, and
material usage amounts and stir time can be obtained by referring
the table 1.
Embodiments 14
[0086] The aforementioned quantum dot solution (2) of 1.25 g and
the aforementioned core solution (4) of 5 g are mixed, and the
mixture is made to stand for 10 minutes. Then, porous micron
particles containing the quantum dots (i.e. the cores attached with
the quantum dots) are obtained after centrifugal filtration. Then,
the porous micron particles containing the quantum dots are added
to ethanol of 250 g and are evenly dispersed. Then,
tetraethoxysilane (TEOS) of 0.5 g, potassium water glass aqueous
solution with a weight percentage of 29% of 0.5 g
(SiO.sub.2:K.sub.2O=2.5:1 w/w; K.sub.2O.nSiO.sub.2, n=2.54) and
NH.sub.4OH with a weight percentage of 29% of 2.5 g are added, and
the solution is stirred for 4 hours at the room temperature, and
now a pH value thereof is 10-11. Then, centrifugal separation is
performed, and then the leftover is cleaned by pure water for three
times, and then a drying process is performed to obtain the micron
level light-emitting material of 0.3289 g.
Embodiments 15-16
[0087] The embodiments 15-16 are the same to the embodiment 14, and
material usage amounts and stir time can be obtained by referring
the table 1.
Comparison Example
[0088] A light-emitting material obtained by removing solvent from
the aforementioned quantum dot solution (1) of 0.25 g
TABLE-US-00001 TABLE 1 Silicon oxide (g) Quantum dot Potassium Stir
solution (g) Core solution (g) water time 1 2 3 4 5 6 7 8 TEOS
glass (hour) Embodiment 1 0.25 0 5 0 0 0 0 0 0.5 0 4 Embodiment 2
0.025 0 5 0 0 0 0 0 0.5 0 4 Embodiment 3 2.5 0 5 0 0 0 0 0 0.5 0 4
Embodiment 4 5 0 5 0 0 0 0 0 0.5 0 4 Embodiment 5 8 0 5 0 0 0 0 0
0.5 0 4 Embodiment 6 0.25 0 0 5 0 0 0 0 0.5 0 4 Embodiment 7 0.25 0
0 5 0 0 0 0 2.5 0 8 Embodiment 8 0.25 0 0 5 0 0 0 0 2.5 0 8 2.5 0 8
Embodiment 9 0.25 0 0 5 0 0 0 0 0 0 Embodiment 10 0.25 0 0 0 0 0 5
0 0.5 0 4 Embodiment 11 0.25 0 0 0 0 0 0 5 0.5 0 4 Embodiment 12
0.25 0 0 0 0 0 0 0 0.5 0 4 Embodiment 13 0 1.25 5 0 0 0 0 0 0.5 0 4
Embodiment 14 0 1.25 0 5 0 0 0 0 0.5 0.5 4 Embodiment 15 0 1.25 0 0
0 5 0 0 0.5 0.5 4 Embodiment 16 0 1.25 0 0 5 0 0 0 0.5 0.5 4
Comparison example 0.25 0 0 0 0 0 0 0 0 0 0
[0089] The weight percentage of the quantum dots, the particle size
of the light-emitting materials, the average distance between the
outermost quantum dots of the particle and the surface of the
particle, and a package layer thickness of the aforementioned
embodiments are shown in a following table 2.
[0090] A result of the PL measurement data and light-emitting
retention ratio (%) of the aforementioned embodiments is shown in
the table 2, in which PL.sub.25 is an intensity of the PL
measurement peak of the light-emitting material at a room
temperature of 25.degree. C., and PL.sub.250 is an intensity of the
PL measurement peak of the light-emitting material after a high
temperature test of 250.degree. C. for 2 hours. The light-emitting
retention ratio (%) is the ratio of PL.sub.250 to PL.sub.25.
TABLE-US-00002 TABLE 2 Minimum Average distance distance between
between outermost outermost Particle quantum quantum size of dots
of the dots of the Light Weight light particle particle Package
emitting percentage emitting and surface and surface layer
retention of quantum material of particle of particle thickness
ratio dots (%) (.mu.m) (nm) (nm) (nm) PL.sub.25 (%) Embodiment 0.9
3.1 3.5 4 4 6.1 .times. 10.sup.5 65 1 Embodiment 0.08 3.0 3.5 4 4
4.2 .times. 10.sup.5 75 2 Embodiment 8.4 3.1 3.5 4 4 9.9 .times.
10.sup.5 63 3 Embodiment 16.8 3.0 4.5 5 5 6.6 .times. 10.sup.5 60 4
Embodiment 21.3 3.1 4.5 5 5 4.4 .times. 10.sup.5 45 5 Embodiment
0.83 1.0 3.5 4 4 6.3 .times. 10.sup.5 69 6 Embodiment 0.6 1.1 17 20
20 5.5 .times. 10.sup.5 69 7 Embodiment 0.37 1.2 34 40 40 1.8
.times. 10.sup.5 67 8 Embodiment 1 1.0 -- -- -- 1.1 .times.
10.sup.6 25 9 Embodiment 0.78 51.3 3.5 4 4 4.6 .times. 10.sup.5 39
10 Embodiment 0.75 3.0 3.5 4 4 1.3 .times. 10.sup.5 36 11
Embodiment 85 0.027 9 10 10 5.7 .times. 10.sup.5 30 12 Embodiment
3.7 1.0 4.5 5 5 8.6 .times. 10.sup.5 74 13 Embodiment 3.8 1.1 7 8 8
8.8 .times. 10.sup.5 68 14 Embodiment 3.2 0.16 7 8 8 9.0 .times.
10.sup.5 75 15 Embodiment 3.5 3.1 7 8 8 8.3 .times. 10.sup.5 63 16
Comparison 100 -- -- -- -- 1.0 .times. 10.sup.6 2 example
[0091] The following phenomena can be found from the aforementioned
experimental data. The light-emitting efficiency of the comparison
example only having the quantum dots without the cores and the
package layer is very poor, since there is no package layer for
protection, and the quantum dots are easily gathered to lose the
light-emitting feature. The light-emitting efficiency of the
embodiment 9 only having the quantum dots and the cores without the
package layer is also poor, since there is no package layer for
protection. The light-emitting efficiency of the embodiment 12 only
having the quantum dots and the package layer without the cores is
also poor, since the quantum dots are easily gathered to lose the
light-emitting feature. In view of the embodiment 11, the surface
of the core has no micropore, so that the quantum dots are easily
gathered, which results in a poor light-emitting efficiency. In
view of the embodiment 10, the particle size of the cores is
excessively large, such that a surface area used for effectively
absorbing the quantum dots under a same volume is decreased, which
results in a fact that the entire quantum dots are easily gathered,
and the PL light-emitting intensity and the light-emitting
retention ratio are all poor. In view of the embodiment 8, the
package layer thickness is greater than 20 nm, and the average
distance between the outermost quantum dots of the particle of
light-emitting material and the surface of the particle of
light-emitting material is also greater than 20 nm, which results
in a fact that the number of the entire quantum dots is low, and
the PL light-emitting intensity and the light-emitting retention
ratio are all poor. Comparatively, the PL light-emitting
intensities and the light-emitting retention ratios of
light-emitting materials of the embodiments 1-7 and the embodiments
13-16 produced according to the method complied with the spirit of
the invention are good.
[0092] In summary, in the light-emitting material, the method for
producing the light-emitting material and the display apparatus,
the quantum dots are located in internal of the light-emitting
material and the light-emitting material presents a granular state,
so that the quantum dots have better high-temperature reliability
and maintain better light-emitting efficiency. The quantum dots
naturally keep enough distance there between and are not gathered
to lose the light-emitting feature. Moreover, the granular micro
level quantum dots are convenient in usage compared to the
nanometer level quantum dots dispersed in the solution.
[0093] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
invention cover modifications and variations of this invention
provided they fall within the scope of the following claims and
their equivalents.
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