U.S. patent application number 12/668359 was filed with the patent office on 2010-08-05 for light-emitting materials for electroluminescent devices.
This patent application is currently assigned to Katholieke Universiteit Leuven. Invention is credited to Gert De Cremer, Dirk De Vos, Johan Hofkens, Lesley Pandey, Maarten Roeffaers, Bert Sels, Tom Vosch.
Application Number | 20100194265 12/668359 |
Document ID | / |
Family ID | 39929721 |
Filed Date | 2010-08-05 |
United States Patent
Application |
20100194265 |
Kind Code |
A1 |
De Cremer; Gert ; et
al. |
August 5, 2010 |
LIGHT-EMITTING MATERIALS FOR ELECTROLUMINESCENT DEVICES
Abstract
The present invention concerns an electroluminescent device that
comprises an anode and cathode separated by intermittent layers or
crystal comprising an assembly of oligo atomic metal clusters
confined in molecular sieve capable of emitting electromagnetic
radiation of one or more colours when a voltage is applied over the
device.
Inventors: |
De Cremer; Gert; (Langdorp,
BE) ; De Vos; Dirk; (Holsbeek, BE) ; Hofkens;
Johan; (Brecht, BE) ; Pandey; Lesley;
(Vilvoorde, BE) ; Roeffaers; Maarten; (Hasselt,
BE) ; Sels; Bert; (Balen, BE) ; Vosch;
Tom; (Kessel-Lo, BE) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE, FOURTH FLOOR
ALEXANDRIA
VA
22314-1176
US
|
Assignee: |
Katholieke Universiteit
Leuven
|
Family ID: |
39929721 |
Appl. No.: |
12/668359 |
Filed: |
July 7, 2007 |
PCT Filed: |
July 7, 2007 |
PCT NO: |
PCT/BE08/00053 |
371 Date: |
January 8, 2010 |
Current U.S.
Class: |
313/503 |
Current CPC
Class: |
G06K 19/06046 20130101;
Y02E 10/52 20130101; C09K 11/58 20130101; H01J 61/44 20130101; C09K
11/02 20130101 |
Class at
Publication: |
313/503 |
International
Class: |
H05B 33/02 20060101
H05B033/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 9, 2007 |
GB |
0713250.9 |
Dec 14, 2007 |
GB |
0724442.9 |
Feb 7, 2008 |
GB |
0802265.9 |
Feb 11, 2008 |
GB |
0802400.2 |
Feb 21, 2008 |
GB |
0803185.8 |
Claims
1-15. (canceled)
16. A light-emitting device comprising: an anode, a cathode and at
least one layer or crystal comprising an assembly of oligo atomic
metal clusters confined in microporous molecular sieves, the metal
clusters being capable of emitting electromagnetic radiation in
response to an electrical voltage applied through the anode and
cathode, wherein said microporous molecular sieves are selected
from the group consisting of zeolites, porous oxides,
silicoaluminophosphates, aluminophosphates, gallophosphates,
zincophosphates, titanosilicates and aluminosilicates, or mixtures
thereof.
17. The light-emitting device according to claim 16, wherein the
anode, the cathode and the layers in between the electrodes
comprising the electroluminescent (EL) material comprise layers on
a substantially transparent substrate.
18. The light-emitting device according to claim 16, wherein the
anode or cathode is transparent or partially transparent.
19. The light-emitting device according to claim 16 wherein one
single crystal of molecular sieves comprising an assembly of oligo
atomic metal clusters is disposed in between an anode and
cathode.
20. The light-emitting device according to claim 16, wherein the
emission layer comprises an assembly of oligo atomic metal clusters
confined in molecular sieves dispersed in a conductive polymer.
21. The light-emitting device according to claim 16, wherein the
emission layer comprises an assembly of oligo atomic metal clusters
confined in molecular sieves dispersed in a non-conductive
polymer.
22. The light-emitting device according to claim 16, wherein the
emission layer comprises a deposited layer of an assembly of oligo
atomic metal clusters confined in molecular sieves.
23. The light-emitting device according to claim 16, wherein the
device is encapsulated from the surrounding atmosphere.
24. The light-emitting device according to claim 16, wherein the
emission layer is part of a cavity in order to achieve lasing.
25. The light-emitting device according to claim 16 used for the
generation of white light and or specific colored light.
26. The light-emitting device according to claim 16 comprising an
assembly of different small Au and/or Ag clusters confined in one
or a combination of multiple molecular sieves to create light at a
predetermined color temperature.
27. The light-emitting device according to claim 16, wherein the
molecular sieves are selected from among microporous materials
selected from the group consisting of zeolites, porous oxides,
silicoaluminophosphates and aluminosilicates.
28. The light-emitting device according to claim 16, wherein the
molecular sieves are zeolites selected from the small pore zeolites
among zeolite A like materials such as zeolite 3A, Zeolite 13X,
Zeolite 4A and Zeolite 5A, and ZKF, and combinations thereof.
29. The light-emitting device according to claim 16, wherein the
molecular sieves are large pore zeolites selected from the group
consisting of Mordenite, ZSM-5, MCM-22, Ferrierite, Faujasites X
and Y.
30. The light-emitting device according to claim 16, wherein the
pores of the molecular sieves containing the small clusters of Au
and/or Ag are coated with a coating matrix.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to white light and
colored light emission using confined metal atomic clusters,
preferably silicium, silver, copper and gold, and more particularly
to the use of molecular sieves comprising oligo atomic silver
clusters as luminescent materials for electroluminescence based
lighting and display applications.
BACKGROUND OF THE INVENTION
[0002] The present invention concerns emissive material of confined
metal oligo atomic clusters in molecular sieves, for instance
zeolites, used in the emissive layer of organic light emitting
devices (OLED) and light emitting diodes (LED).
[0003] LED's have been around since the 1960's and have known a
constant evolution, the latest developments being bright blue and
white LED's. These LED's require high purity semiconductor material
which usually entail high production costs. Emission of coloured
LED's generally consists of narrow-spectrum light of a predefined
wavelength dependant on the material used, making it difficult to
tune the emission colour. The present invention provides an
alternative for the current semiconductor materials at lower
production cost and greater ease of tuning the emission spectrum of
the LED.
[0004] OLED's are a far more recent innovation and have known an
increasing interest as an alternative to current display (e.g.
plasma, LCD) and lighting (e.g. fluorescent lamps) technologies
because of the numerous advantages they offer, such as: low
production cost, ease of manufacture, wide viewing angle, high
efficiency, possibility of flexible displays, high contrast, large
area, . . . However, it's development has been curbed by several
factors. One of the most challenging problems is the limited
lifetime of the organic materials used in the fabrication of
OLED's. During the first experiments with OLED's the emission
intensity halved after only 100 hours of operation (Ref Tang, C.
W., Van Slyke, S. A., Appl. Phys. Lett., 1987, 51, 913). Nowadays
(extrapolated) lifetimes of more then 20.000 hours at 400
cd/m.sup.2 have been reported (Ref: Cambridge Display Technologies,
Press release, Jun. 9, 2006). Although this is sufficient for
displays; lighting applications require a luminance of at least
1000 cd/m.sup.2, resulting in far lower lifetimes. The most
important causes of degradation are oxygen and moisture, therefore
OLED's need to be properly sealed from the surrounding atmosphere.
The use of air stable compounds can mean a strong reduction of
production cost and time, and an increase in operation
lifetime.
[0005] All OLED's and LED's are based on the same basic principle:
one or more layers of organic or inorganic semiconductors are
sandwiched between two electrodes. An electric field is applied
over this layer(s) causing electrons and holes to be injected in
the layer(s) from the cathode and anode. These charges recombine in
the semiconductor creating an excited state. The excited state then
relax back to a non-excited state by emitting a photon. The
wavelength of the emitted light therefore depends on the properties
of the recombination centre.
[0006] Present invention proposes the use of metal oligo atomic
clusters as recombination centre. In contrast to bulk metals which
are devoid of a band gap, small metal oligo atomic clusters display
interesting emissive properties from discrete energy levels. This
phenomenon has been demonstrated e.g., for silver smaller than 100
atoms in rare gas matrices, in aqueous solutions and on silver
oxide films. Quantum chemical calculations confirm the molecular
character and discrete energy states of these small silver
clusters. (Ref 1. Johnston, R. L. (2002) Atomic and Molecular
Clusters (Taylor & Francis, London and New York); Rabin, I.,
Schulze, W., Ertl, G., Felix, C., Sieber, C., Harbich, W., &
Buttet, J. (2000) Chemical Physics Letters 320, 59-64; Peyser, L.
A., Vinson, A. E., Bartko, A. P., & Dickson, R. M. (2001)
Science 291, 103-106; Lee, T. -H., Gonzalez, J. I., & Dickson,
R. M. (2002) Proc. Natl. Acad. Sci. USA 99, 10272-10275; Lee, T.
H., Gonzalez, J. I., Zheng, J., & Dickson, R. M. (2005)
Accounts of Chemical Research 38, 534-541; Bonacic-Koutecky, V.,
Mitric, R., Burgel, C., Noack, H., Hartmann, M., & Pittner, J.
(2005) European Physical Journal D 34, 113-118; Lee, T. -H.,
Hladik, C. R., & Dickson, R. M. (2003) Nano Letters 3,
1561-1564; Rabin, I., Schulze, W., & Ertl, G. (1999) Chemical
Physics Letters 312, 394-398; Felix, C., Sieber, C., Harbich, W.,
Buttet, J., Rabin, I., Schulze, W., & Ertl, G. (1999) Chemical
Physics Letters 313, 105-109; Rabin, I., Schulze, W., & Ertl,
G. (1998) Crystal Research and Technology 33, 1075-1084; Rabin, I.,
Schulze, W., & Ertl, G. (1998) Journal of Chemical Physics 108,
5137-5142; Konig, L., Rabin, I., Schulze, W., & Ertl, G. (1996)
Science 274, 1353-1355; Zheng, J. & Dickson, R. M. (2002)
Journal of the American Chemical Society 124, 13982-13983;
Bonacic'-Koutecky, V., Veyret, V., & Mitric', R. (2001) Journal
of Chemical Physics 115, 10450-10460; Bonacic-Koutecky, V.,
Pittner, J., Boiron, M., & Fantucci, P. (1999) Journal of
Chemical Physics 110, 3876; Bonacic'-Koutecky, V., Cespiva, L.,
Fantucci, P., & Koutecky, J. (1993) Journal of Chemical Physics
98, 7981-7994; Yoon, J., Kim, K. S., & Baeck, K. K. (2000)
Journal of Chemical Physics 112, 9335-9342; Fedrigo, S., Harbich,
W., & Buttet, J. (1993) Journal of Chemical Physics 99,
5712-5717.
[0007] The major problem in the study and creation of small metal
oligo atomic clusters is aggregation to large nanoparticles and
eventually to bulk metal, with loss of emission. Here, it is
demonstrated that the use of porous structures with limited pore,
cavity and channel sizes, overcomes the aggregation problem
enabling emissive entities, which are stable in time.
[0008] The materials of present invention, for instance zeolites
containing oligo silver atom clusters exhibit remarkable stability,
based on absorbance measurements in mordonites. (Ref Bogdanchikova,
N. E., Petranovskii, V. P., Machorro, R., Sugi, Y., Soto, V. M.,
& Fuentes, S. (1999) Applied Surface Science 150, 58-64)
Bogdanchikova et al. found that the stability of the silver
clusters depends on the acid strength, which may be related to the
composition, e.g., the SiO.sub.2/Al.sub.2O.sub.3 molar ratio, of
the molecular sieves. Silver clusters in mordenites having weak
acidic sites are stable for at least 50 months, a sufficiently long
period with respect to the applications in mind for use in a
visible light source. Disappearance of the clusters was linked to
oxidation. Reduction of the clusters or an oxygen-free or -poor
device obviously can increase the stability even more. In the
present invention, metal oligo atomic clusters are protected from
oxidation due to encapsulation in the molecular sieves.
Additionally, if necessary, an external coating of the material
crystals or capping of the pore entrances can be used to further
protect the occluded metal clusters.
[0009] Silver clusters in molecular sieves are cheap and non toxic.
Zeolites are currently used in large quantities in washing powder
and silver despite its antimicrobial properties, has no known toxic
effect on human tissue. Colloidal silver has for instance widely
been marketed as a dietary supplement for protective activity
against oxidative stress and reactive oxygen species formation.
[0010] In recent years, expertise has been gained in the synthesis
of zeolites with desired properties by the choice of the structure
directing agent (SDA), control of the synthesis conditions, and
post-synthesis treatments. (Ref van Bekkum, H., Flanigen, E. M.,
Jacobs, P. A., Jansen, J. C. (editors) Introduction to Zeolite
Science and Practice, 2nd edition. Studies in Surface Science and
Catalysis, 2001, 137; Corma, A., Chem. Rev., 1997, 97, 2373-2419;
Davis, M. E., Nature, 2002, 417, 813-821; Davis, M. E., et al.,
Chem. Mater., 1992, 4, 756-768; de Moor P -P. E. A. et al., Chem.
Eur. J., 1999, 5(7J, 2083-2088; Galo, J de A. A., et al., Chem.
Rev., 2002, 102, 4093-4138) At the same time, the family of ordered
mesoporous materials has been greatly expanded by the use of
different surfactants and synthesis conditions. (Ref Corma, A.,
Chem. Rev., 1997, 97, 2373-2419; Davis, M. E., Nature, 2002, 417,
813-821; Galo, J. de A. A., et al., Chem. Rev., 2002, 102,
4093-4138; Ying, J. Y., et al., Angew. Chem. Int. Ed., 1999, 3S,
56-77) The use of the appropriate template enables the control of
the pore size, distribution and connectivity during the zeolite
synthesis. For example, use of surfactants such as
cetyltrimethylammonium bromide or dodecyltrimethylammonium bromide
generally results in formation of mesoporous materials. In a
preferred embodiment, the molecular sieves are one or more selected
from the group consisting of mordenite, ZSM-5, A-zeolite,
L-zeolite, faujasite, ferrierite, chabazite type of zeolites, and
mixtures of the foregoing zeolites.
[0011] The use of stable inorganic metal nanoclusters as dopant is
a further improvement, as degradation will be negligible with these
inorganic systems. In summary, the current state of the art has
never suggested or demonstrated the conversion of an electric
current to visible light, by oligo atomic metal clusters embedded
in molecular sieves.
[0012] Present invention concerns the field of lighting devices,
and related, comprising e.g., white light and colored luminescent
materials with emission of visible white or colored light. Such
devices thus comprise luminescent materials for electroluminescence
based lighting generated through the action of confined metal oligo
atomic clusters, more particularly oligo atomic silver clusters
loaded in molecular sieves (e.g., LTA zeolites, Linde Type A
zeolites).
SUMMARY OF THE INVENTION
[0013] The present invention solves problems of the related art by
providing highly stable electroluminescent materials for use in
display and lighting technologies.
[0014] In accordance with the purpose of the invention, as embodied
and broadly described herein, the invention is broadly drawn to an
illuminating device comprising one or more layers containing an
electroluminescent (EL) material in contact with an anode and
cathode. The anode and cathode are electrically isolated from one
and other. If an electrical field or voltage is applied over the
anode and cathode, the EL material will emit electromagnetic
radiation. In accordance with the purpose of the invention, the
invention comprises an assembly of small clusters of the noble
metals of the group consisting of gold, silver, copper, platinum,
palladium, silicium, rhodium, nickel, iridium and cobalt preferably
Au and/or Ag clusters confined in molecular sieves, preferably
zeolites, as EL material.
[0015] Under voltage such EL material can emit an electromagnetic
radiation for instance in the ultraviolet to visible and infrared
region of the electromagnetic spectrum. The preferred voltage to
activate the EL material to emit electromagnetic radiation is a
voltage of 0.05 to 100 volt, more preferably 0.1 to 50 volt, yet
more preferably 0.2 to 25 volt, yet more preferably 0.5 to 15 volt
and most preferably 1 to 10 volt.
[0016] The molecular sieves doped with metal clusters can be
dispersed in a getter material or deposited as a single layer, or
even a single crystal, between the anode and cathode. The getter
material can consist of one or more conducting or non-conducting
polymers or small molecule compounds. A conducting getter material
can be used to achieve higher efficiency by facilitating charge
transport to the metal clusters.
[0017] The illumination system can be used for the generation of
white light and or specific colored light and at a predetermined
color temperature.
[0018] The clusters in the illumination system of present invention
are oligo atomic clusters of 1-100 atoms. The molecular sieves in
this invention are selected from the group consisting of zeolites,
porous oxides, silicoaluminophosphates, aluminophosphates,
gallophosphates, zincophophates, titanosilicates and
aluminosilicates, or mixtures thereof. In a particular embodiment
of present invention the molecular sieves of present invention are
selected from among large pore zeolites from the group consisting
of MCM-22, ferrierite, faujastites X and Y. The molecular sieves in
another embodiment of present invention are materials selected from
the group consisting of zeolite 3A, Zeolite 13X, Zeolite 4A,
Zeolite 5A and ZKF.
[0019] In a particular embodiment of present invention the pores of
the molecular sieves containing the small clusters of, e.g., Au
and/or Ag are coated with a matrix, or are closed by stopper
molecules.
[0020] The light system of present invention does not require the
presence of charge compensating anions, such as oxalate, hydroxide,
azide, carbonate, bicarbonate, sulfate, sulfite, chlorate,
perchlorate, acetate and formate to be in charge association with
the noble metals, such as the small metal clusters.
[0021] Further scope of applicability of the present invention
becomes apparent from the detailed description given hereinafter.
However, it should be understood that the detailed description and
specific examples, while indicating preferred embodiments of the
invention, are given by way of illustration only, since various
changes and modifications within the spirit and scope of the
invention will become apparent to those skilled in the art from
this detailed description. It is to be understood that both the
foregoing general description and the following detailed
description are exemplary and explanatory only and are not
restrictive of the invention, as claimed.
DETAILED DESCRIPTION
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0022] An "OLED" is a light-emitting device that can emit light,
having a wavelength in the visual range, if an electric current is
passed through the device. It comprises one or more layers, which
can have the role of charge transport, blocking or emission layer,
positioned between 2 electrodes.
[0023] An "LED" is a light-emitting device that can emit light,
having a wavelength in the visual range, if an electric current is
passed through the device. It comprises a crystal of EL material
positioned between 2 electrodes.
[0024] Oligo atomic metal clusters include clusters ranging from 1
to 100 atoms of the following metals (sub nanometer size), Si, Cu,
Ag, Au, Ni, Pd, Pt, Rh, Co and Ir or alloys thereof such as Ag/Cu,
Au/Ni etc. The clusters can be neutral, positive or negatively
charged. The oligo atomic metal clusters can be small oligo atomic
silver- (and/or gold) molecules containing 1 to 100 atoms.
[0025] The articles "a" and "an" are used herein to refer to one or
more than one (i.e., at least one) of the grammatical object of the
article. By way of example, "an element" means one element or more
than one element.
[0026] The terms "comprise" and "comprising" are used in the
inclusive, open sense, meaning that additional elements may be
included.
[0027] The term "including" is used to mean "including but not
limited to". "Including" and "including but not limited to" are
used interchangeably.
[0028] The term "in particular" is used to mean "in particular but
not limited to". And the term "particularly" is used to mean
"particularly but not limited to"
[0029] The term "zeolite" also refers to a group, or any member of
a group, of structured aluminosilicate minerals comprising cations
such as sodium and calcium or, less commonly, barium, beryllium,
lithium, potassium, magnesium and strontium; characterized by the
ratio (Al+Si):O=approximately 1:2, an open tetrahedral framework
structure capable of ion exchange, and loosely held water
molecules, that allow reversible dehydration. The term "zeolite"
also includes "zeolite-related materials" or "zeotypes" which are
prepared by replacing Si.sup.4+ or Al.sup.3+ with other elements as
in the case of aluminophosphates (e.g., MeAPO, SAPO, ElAPO, MeAPSO,
and ElAPS0), gallophosphates, zincophophates, titanosilicates, etc.
The zeolite can be a crystalline porous material with a frame work
as described in Pure Appl. Chem., Vol. 73, No. 2, pp.
381-394,.COPYRGT. 2001 IUPAC or provided in the Zeolite Framework
Types database of the IZA structure commission where under the
following structure types, as defined by the International Zeolite
Association such as ABW type, ACO type, AEI type, AEL type, AEN
type, AET type, AFG AFI type, AFN type, AFO type, AFR type, AFS
type, AFT type, AFX type, AFY type, AHT type, ANA type, APC type,
APD type, AST type, ASV type, ATN type, ATO type, ATS type, ATT
type, ATV type, AWO type, AWW type, BCT type, *BEA type, BEC type,
BIK type, BOG type, BPH type, BRE type, CAN type, CAS type, CDO
type, CFI type, CGF type, CGS type, CHA type, --CHI type, --CLO
type, CON type, CZP type, DAC type, DDR type, DFO type, DFT type,
DOH type, DON type, EAB type, EDI type, EMT type, EON type, EPI
type, ERI type, ESV type, ETR type, EUO type, EZT type, FAR type,
FAU type, FER type, FRA type, GIS type, GIU type, GME type, GON
type, GOO type, HEU type, IFR type, IHW type, IMF type, ISV type,
ITE type, ITH type, ITW type, IWR type, IWV type, IWW type, JBW
type, KFI type, LAU type, LEV type, LIO type, -LIT type, LOS type,
LOV type, LTA type, LTL type, LTN type, MAR type, MAZ type, MEI
type, MEL type, MEP type, MER type, MFI type, MFS type, MON type,
MOR type, MOZ type, MSE type, MSO type, MTF type, MTN type, MTT
type, MTW type, MWW type, NAB type, NAT type, NES type, NON type,
NPO type, NSI type, OBW type, OFF type, OSI type, OSO type, OWE
type, --PAR type, PAU type, PHI type, PON type, RHO type, --RON
type, RRO type, RSN type, RTE type, RTH type, RUT type, RWR type,
RWY type, SAO type, SAS type, SAT type, SAV type, SBE type, SBN
type, SBS type, SBT type, SFE type, SFF type, SFG type, SFH type,
SFN type, SFO type, SGT type, SIV type, SOD type, SOS type, SSF
type, SSY type, STF type, STI type, *STO type, STT type, SZR type,
TER type, THO type, TOL type, TON type, TSC type, TUN type, UEI
type, UFI type, UOZ type, USI type, UTL type, VET type, VFI type,
VNI type, VSV type, WEI type, --WEN type, YUG type and ZON type.
The term "zeolite" also includes "zeolite-related materials" or
"zeotypes" which are prepared by replacing Si4+ or Al3+ with other
elements as in the case of aluminophosphates (e.g., MeAPO, AlPO,
SAPO, ElAPO, MeAPSO, and ElAPSO), gallophosphates, zincophophates,
titanosilicates, etc.
[0030] The term "molecular sieves" as used herein refers to a solid
with pores of the size of molecules. It includes, but is not
limited to microporous and mesoporous materials. In the
nomenclature of the molecular sieves the pore size of <20
Amstrong (.ANG.) is considered microporous and 20-500 .ANG. is
considered mesoporous.
[0031] The term "microporous carrier" as used herein refers to a
solid with pores the size of molecules. It includes but is not
limited to microporous materials, ALPOs and (synthetic) zeolites,
pillared or non-pillared clays, carbon molecular sieves,
microporous titanosilicates such as ETS-10, microporous oxides.
Microporous carriers can have multimodal pore size distribution,
also referred to as ordered ultramicropores (typically less than
0.7 nm) and supermicropores (typically in the range of about 0.7-2
nm). A particular type of microporous carriers envisaged within the
present invention, are the molecular sieve zeolites. Zeolites are
the aluminosilicate members of the family of microporous carriers.
The pore size of molecular sieves can further be influenced by the
nature of the templating molecules in the synthesis. The addition
of swelling agents to the synthesis mixture can further affect the
pore size of the resulting molecular sieve. Zeolites with different
pore size have been well characterized and described by Martin
David Foster in "Computational Studies of the Topologies and
Properties of Zeolites", The Royal Institution of Great Britain,
Department of Chemistry, University College London, a thesis
submitted for the degree of Doctor of Philosophy, London, January
2003.
[0032] A comprehensive list of the abbreviations utilized by
organic chemists of ordinary skill in the art appears in the first
issue of each volume of the Journal of Organic Chemistry; this list
is typically presented in a table entitled Standard List of
Abbreviations.
[0033] For purposes of this invention, the chemical elements are
identified in accordance with the Periodic Table of the Elements,
CAS version, Handbook of Chemistry and Physics, 67th Ed., 1986-87,
inside cover. [Contemplated equivalents of the zeolitic structures,
subunits and other compositions described above include such
materials which otherwise correspond thereto, and which have the
same general properties thereof (e.g., biocompatible), wherein one
or more simple [variations of substituents are made which do not
adversely affect the efficacy of such molecule to achieve its
intended purpose. In general, the compounds of the present
invention may be prepared by the methods illustrated in the general
reaction schemes as, for [example, described below, or by
modifications thereof, using readily available starting materials,
reagents and conventional synthesis procedures. In these reactions,
it is also possible to make use of variants which are in themselves
known, but are not mentioned here.
[0034] a. "the molecular sieve matrix is selected from among
microporous materials, selected from among zeolites, porous oxides,
silicoaluminophosphates and aluminosilicates"
[0035] b. "zeolite selected from among the family of small pore
sized zeolites such as zeolite A and ZKF, and combinations
thereof"
[0036] c. "large pore zeolites such as ZSM-5, MCM-22, ferrierite,
faujastites X and Y and microporous molecular sieves"
[0037] d. "The matrix can also be a molecular sieve selected from
among molecular sieves MCM-41, MCM-48, HSM, SBA-15, and
combinations thereof"
[0038] e. "Methods are available in the art for preparation of
microporous zeolites."
[0039] f. "As used herein, microporous zeolites preferably have a
pore size of about 3 angstroms to about 14 angstroms"
[0040] The term microporous materials also include amorphous
microporous solids. Alternative amorphous microporous solids can be
used for present invent. For instance amorphous microporous mixed
oxides having, in dried form, a narrow pore size distribution (half
width <.+-.10% of the pore diameter) of micropores with
diameters in the range of <3 nm and the preparation of said
amorphous microporous mixed oxides have been well described in U.S.
Pat. No. 6,121,187 and others have been well documented in
WO0144308, U.S. Pat. No. 6,753,287, U.S. Pat. No. 6,85,5304, U.S.
Pat. No. 6,977,237, WO2005097679, U.S. Pat. No. 7,055,756 and U.S.
Pat. No. 7,132,093" Several documents are cited throughout the text
of this specification. Each of the documents herein (including any
manufacturer's specifications, instructions etc.) are hereby
incorporated by reference; however, there is no admission that any
document cited is indeed prior art of the present invention.
[0041] The oligo atomic metal clusters confined in molecular sieves
or microporous structures can be incorporated in membranes or films
for instance by embedding in transparent matrix materials such as
silicone, epoxy, adhesives, polymethylmethacrylate, polycarbonate.
Moreover the molecular sieves or the ordered comprising oligo
atomic silver clusters of present invention can be incorporated in
paints or fluids of film formers for coating on surface surfaces.
Media (paints, gelling liquids, elastomers) are available and
methods of manufacturing to achieve such membranes or films, for
instance a filled elastomeric polymer, which comprise the
oligo-atomic metal clusters confined in molecular sieves or in
ordered porous oxides (microporous or mesoporous or mixed
mesoporous/microporous) or porous materials with nanometer
dimension (0.3-10 nm) windows, channels and cavity architectures.
Typical but not exclusive examples of such elastomeric polymers are
polydimethylsiloxane (silicone rubber), polyisobutene (butyl
rubber), polybutadiene, polychloroprene, polyisoprene,
styrene-butadiene rubber, acrylonitrile-butadiene rubber (NBR),
ethene-propene-diene-rubber (EPDM) and
acrylonitrile-butadiene-styrene(ABS). Such films or membranes of
the molecular sieves comprising oligo atomic silver clusters;
ordered mesoporous and/or microporous oxides comprising oligo
atomic silver clusters or porous materials with nanometer dimension
(e.g. 0.3-10 nm) windows, channels and cavity architectures
comprising oligo atomic silver clusters can be coated on a
substrate. Following the ASTM (American Society for Testing and
Materials) standards, `elastomers` are defined as "macromolecular
materials that return to approximately the initial dimensions and
shape after substantial deformation by a weak stress and release of
the stress". Elastomers are sometimes also referred to as `rubbery
materials`. A `rubber` is defined as "a material that is capable of
recovering from large deformations quickly and forcibly, and can
be, or already is, modified to a state in which it is essentially
insoluble (but can swell) in boiling solvent, such as benzene,
toluene, methyl ethyl ketone, and ethanol/toluene azeotrope".
[0042] In the preparation of membranes with the oligo atomic metal
clusters confined in the microporous structures, the microporous
structures are first dispersed in an appropriate solvent. An
appropriate solvent is a solvent of low ionic strength, for
instance an ionic strength of a value in the range of 1 mmol/L to
0.05 mol/L, and should be able to dissolve the elastomer as well,
or at least, should be partially miscible with the solvent in which
the membrane forming polymer is dissolved. To improve the
dispersion, ultrasonic wave treatment, high speed mixing,
modification reactions, can be applied. The content of porous
structures with oligo atomic metal clusters confined therein and
polymer, in the dispersion, may range from 1 wt % to 80 wt %,
preferably 20 wt % to 60 wt %. The dispersion is stirred for a
certain time to allow (polymer/filler) interactions to establish,
to improve dispersion and possibly to let a chemical reaction take
place. When appropriate, the dispersion can be heated or
sonicated.
[0043] The metal clusters in microporous materials are in molecular
sieves or microporous structures, may be incorporated in paints or
printing inks (e.g. printable matrix printing ink or printable
paints, varnishes (e.g. overprinting varnishes) and paints for
depositing, spraying, printing or painting a layer or a coating on
a substrate. Printing inks or paints of the art which are suitable
for comprising the emitting materials of present invention are for
instance hard resins, colophony-modified phenol resins, maleate
resins, hydrogenated mineral oil cuts, synthetic aromatic oils,
alkyd resins in particular hydrocarbon resins and/or a colophony
resin ester and dialkyl ether such as di-n-dodecyl ether,
di-n-undecyl ether, allyl-n-octyl ether, n-hexyl-n-undecyl ether as
a vehicle. Particular suitable solvents are the resin(s)
water-insoluble fatty acid esters of polyvalent alcohols or
ethinols. Suitable printing inks in the art are described in U.S.
Pat. No. 4,028,291, U.S. Pat. No. 4,169,821, U.S. Pat. No.
4,196,033, U.S. Pat. No. 4,253,397, U.S. Pat. No. 4,262,936, U.S.
Pat. No. 4,357,164, U.S. Pat. No. 5,075,699, U.S. Pat. No.
5,286,287, U.S. Pat. No. 5,431,721, U.S. Pat. No. 5,886,066, U.S.
Pat. No. 5,891,943, U.S. Pat. No. 6,613,813 and U.S. Pat. No.
5,965,633. Such emitting material of present invention may be
painted, printed or coated on the substrate.
[0044] Solvent casting or coating is used as the membrane
preparation process.
[0045] A particular method of coating is solution-depositing of the
molecular sieves comprising oligo atomic silver clusters comprises
spray-coating, dip-casting, drop-casting, evaporating,
blade-casting, or spin-coating the molecular sieves comprising
oligo atomic silver clusters; ordered mesoporous and/or microporous
oxides comprising oligo atomic silver clusters or porous materials
with nanometer dimension (e.g. 0.3-10 nm) windows, channels and
cavity architectures with an assembly of oligo atomic metal
clusters confined in such structures (hereinafter the porous
structures with oligo atomic metal clusters confined therein) onto
a substrate.
[0046] The (polymer/porous structures with oligo atomic metal
clusters confined therein) dispersion can be cast on a non-porous
support from which it is released afterwards to form a
self-supporting film. One way tot realise this is by soaking it
previously with a solvent, which has a low affinity for the
dispersion. Also, the support can be treated with adhesion
promoters.
[0047] After casting or coating, the solvent is evaporated and, if
necessary, a heat treatment can be applied to finish the
cross-linking reactions. The heat treatment can possibly occur
under vacuum conditions to remove the remaining solvent. The
resulting supported membranes be a filled elastomer with the
thickness of this selective layer in a range from 0.01 .mu.m to 500
.mu.m, preferably from 0.1 to 250 .mu.m and yet more preferably
from 10 to 150 .mu.m.
[0048] The most important elastomers are polyisoprene (natural or
synthetic rubber (IR)), polychloroprene (chloroprene rubber (CR)),
butyl rubber (BR), styrene-butadiene rubber (SBR),
acrylonitrile-butadiene rubber (NBR), ethene-propene-diene-rubber
(EPDM), acrylonitrile-butadiene-styrene (ABS), chlorosulfonated
polyethylene (CSM), I polyacrylate (polyacrylic rubber),
polyurethane elastomers, polydimethylsiloxane (PDMS, sometimes more
generally referred to as silicone rubber), fluorosilicones and
polysulfides. Polystyrene is a thermoplastic polymer that
particularly resistant to irradiation.
[0049] The films with the porous structures of present invention
may need particular characteristics according to its environment of
use. A variety of alternatives polymers that provide design freedom
which preparation protocols are available in the art to design
complex shapes, to consolidate parts into fewer components,
simplify production, to produce transparent and precolored
components, to reduce part weight, to reduce noise when the porous
structures with oligo atomic metal clusters is moving, to have a
reliable performance at elevated temperature, to have chemical
resistance in harsh climates, to have the desired stiffness,
strength and toughness, to have hydrolytic stability over time, to
have electrical properties to have a desired physical
appearance.
[0050] Polymers that are suitable for incorporation of the porous
structures of present invention are for instance Spire.TM. family
of ultra polymers such as 1) KetaSpire.RTM. polyetheretherketone
(PEEK) which is easy-to-mold ultra polymer offering outstanding
chemical resistance and mechanical performance up to 300.degree. C.
(570.degree. F.) or AvaSpire.RTM. modified PEEK, a PEEK-based
formulations or 2) PrimoSpire.RTM. self-reinforced polyphenylene
(SRP) known to be designable in a very stiff, strong unreinforced
polymer with a remarkable combination of surface hardness, chemical
resistance and inherent flame-retardant properties or 3)
EpiSpire.TM., an high-temperature sulfone (HTS) known to be a
transparent amorphous polymer with excellent creep resistance at
temperatures up to 265.degree. C. (510.degree. F.) or 4)
Torlon.RTM. polyamide-imide (PAI) with higher strength and
stiffness that most thermoplastic up to 275.degree. C. (525.degree.
F.) combined with superior resistance to chemicals, creep and wear.
Other polymers that are suitable for incorporation of the porous
structures with oligo atomic metal clusters confined therein of
present invention are the family of amorphous sulfone polymers such
as 1) Udel.RTM. PSU known to be designable into tough, transparent
plastic with exceptional chemical resistance, good hydrolytic
stability and an HDT of 345.degree. F. (174.degree. C.) or the 2)
Mindel.RTM. modified polysulfone with superior electrical
properties or 3) the Radel.RTM. R (PPSU) known to deliver a
super-tough transparent plastic with an HDT of 405.degree. F.
(207.degree. C.), excellent chemical resistance and the unique
ability to be steam sterilized without significant loss of
properties or 4) the Radel.RTM. A (PES) know to deliver a
transparent plastic with a high HDT of 400.degree. F. (204.degree.
C.) and good chemical resistance or the Acudel.RTM. modified PPSU.
Other polymers that are suitable for incorporation of the porous
structures with oligo atomic metal clusters confined therein of
present invention are for instance the semi-crystalline aromatic
polyamides such as for instance the Arnodel.RTM. polyphthalamide
(PPA) known to deliver a high-temperature nylon with exceptional
mechanical properties, an HDT of 535.degree. F. (280.degree. C.),
excellent chemical resistance and low moisture uptake or the
Ixef.RTM. polyarylamide (PA MXD6) known to deliver aesthetic,
structural specialty nylon that combines outstanding stiffness with
exceptional surface appearance, plus low and slow water uptake, and
great flow properties. Other polymers that are suitable for
incorporation of the porous structures with oligo atomic metal
clusters confined therein of present invention are for instance
semi-crystalline polymers such as the Primef.RTM. polyphenylene
sulfide (PPS) which delivers a high-flow, structural plastic with
good temperature and chemical resistance as well as inherent flame
retardant properties or the Xydar.RTM. liquid crystal polymer (LCP)
known to deliver high-flow, high-temperature plastic with an HDT of
570.degree. F. (300.degree. C.), and extremely high chemical
resistance. These are available with design and processing guides
form Solvay Advanced Polymers.
[0051] A particular example of manufacturing emitting film based on
the porous structures oligo atomic metal clusters confined therein
of present invention and a polymer is for instance the use of
polydimethylsiloxane (PDMS), RTV-615 A and B (density 1.02 g/ml)
and the adhesion promoter (SS 4155) which are obtainable from
General Electric Corp. (USA). Component A is a prepolymer with
vinyl groups. Component B has hydride groups and acts as
cross-linker and EPDM (Keltan 578 from DSM) and porous structures
with oligo atomic metal clusters confined therein of present
invention which are well dried before use.
[0052] Such can be produced by preparing dispersing a powder of the
porous structures with oligo atomic metal clusters confined therein
of present invention (for instance a zeolite comprising oligo
atomic silver clusters) in hexane adding the cross-linker (RTV 615
B) to the dispersion of porous structures with oligo atomic metal
clusters confined therein of present invention and stirring this
this mixture at 40.degree. C. for two hours to allow sufficient
time to establish strong interactions between both phases. Adding
the prepolymer (RTV 615 A) and stirring the mixture for another
hour at 60.degree. C. to induce prepolymerisation. Pouring the
(PDMS/ZSM-5 CBV 3002) in a petri dish and allowing the solvent to
evaporate for several hours and the resulting film was cured at
100.degree. C. The content of the solid components (i.e. PDMS and
filler) in the casting solution was 18.5 wt %. The RTV 615 A/B
ratio for optimal polymer curing was 7 in order compensate for the
loss of hydride groups due to their reaction with the surface
silanol groups on the zeolite (normally it is in a 10/1 ratio, as
proposed by the manufacturer to be the ratio for optimal
curing).
[0053] For flexible substrates thermoplastics (e.g., Polyethylene
naphthalate (PEN), Polyethersulfone (PES), Polycarbonate (PC),
Polyethylene terephthalate (PET), Polypropylene (PP), oriented
polypropylene (OPP), etc.), and glass (e.g., borosilicate)
substrates may be used for these applications. Low liquidus
temperature material, which typically has a low liquidus
temperature (or in specific embodiments a low glass transition
temperature can be used form a barrier layer on a flexible
substrate and can be can be deposited onto the flexible substrate
by, for example, sputtering, co-evaporation, laser ablation, flash
evaporation, spraying, pouring, frit-deposition, vapor-deposition,
dip-coating, painting or rolling, spin-coating, or any combination
thereof. The porous structures with oligo atomic metal clusters
confined therein can be incorporated into the low liquidus
temperature materials. Such low liquidus temperature material
includes, but is not limited to, tin fluorophosphate glass,
chalcogenide glass, tellurite glass and borate glass.
Examples
Example 1
Preparation of the Emissive Materials
[0054] Various methods for the production of metal ion exchanged
molecular sieves are available in the art. A method similar as
described by Jacobs et al. (Jacobs, P. A. & Uytterhoeven, J.
B., 1979, Journal of the Chemical Society-Faraday Transactions I
75, 56-64) was used for incorporating silver ions in molecular
sieves and creating silver clusters. However lots of parameters
like loading percentage of the zeolites, exchange time, length of
temperature treatment, initial, gradient and final temperature of
the temperature treatment, presence of gasses during the
temperature treatment (e.g. in vacuum, in presence of oxygen, in
presence of oxygen and nitrogen, in presence of hydrogen, in
presence of CO and/or CO.sub.2 gas) and the presence of moisture in
the air influences the finally formed types of clusters, oxidation
state of the clusters and distribution and polydispersity of the
types of clusters formed.
Example 2
Emission
[0055] It was demonstrated that metal cluster especially silver in
confined molecular sieves have a distinct and tunable emission
throughout the VIS and NIR part of the electromagnetic spectrum.
Thanks to the host matrix the confined metal clusters are prevented
from aggregation with each other to form bigger non emissive
nanoparticles. Also they can be shielded from the outside
environment (e.g. oxygen) if required by adding a silicon coating
around the molecular sieves.
Example 3
Modified OLED Building Scheme
[0056] The molecular sieve materials and mixtures thereof can be
used as emissive material in OLED's either as dopant in a matrix
layer or as a pure layer. This layer then emits visible (white)
light. The materials now currently used in OLED's as dopants in the
emission layer can be replaced by the present invention; molecular
sieves containing metal clusters. FIG. 1 shows a schematic drawing
of a possible design. By mixing metal cluster containing molecular
sieves with different sized clusters, a variety of spectral
properties can be generated. By changing the ratios of the mixed
materials a whole range of light colors can be generated, including
white light. If one however wants light of a particular color, one
can select molecular sieves with uniform sized metal clusters.
[0057] For the preparation of an OLED a 3A zeolite was exchanged
with silver (10% weight) and then thermally treated (24 hours at
450.degree. C.) resulting in a partial reduction and formation of
small silver clusters in the host matrix. 0.4 mg of these silver
loaded zeolites were added to 1 ml of a 20 mg/ml PVK
(poly-N-vinylcarbazole) in chlorobenzene solution. From this
solution a film was spincoated on a ITO covered glass substrate.
Ytterbium was then evaporated through a patterning mask on the
spincoated film as a second electrode. After applying an electric
field over this device, in which ITO functioned as anode and
ytterbium as cathode, red electroluminescence was observed. The
emission spectrum of this electroluminescence is shown in FIG. 2.
The synthesis of the oligo metal clusters with the desired emissive
properties can be tuned by changing the synthesis parameters.
Example 4
Modified LED Building Scheme
[0058] A LED can be constructed by placing a single zeolite crystal
or layer loaded with metal clusters in between two electrodes as
shown in FIG. 3. This material can provide considerable advantages
for white LED's in reference to the current state of the art by
making it possible to generate an emission spectrum similar to that
of black body emission. Currently the white emission is mostly
realized by a blue emitter surrounded by a yellow emitting
phosphor. The resulting emission approaches white, but gives a
rather cold and grey impression due to the fact that the emission
spectrum consists of two emission spikes rather then a broad band.
By using a zeolite crystal loaded with metal clusters of different
sizes, it is possible to generate an emission which covers the
whole visual range. Using zeolite crystals with metal clusters of
the same size, single color LED's can be made as well.
Example 5
Modified Organic Lasers
[0059] Electrically pumped organic lasers as yet have not been
realized. One of the reasons for this is the high current densities
necessary for lasing at which most organic materials disintegrate
and device breakdown occurs. The inorganic system proposed here
will provide an interesting alternative due to its higher stability
at high current densities. The structure of such a laser system
will be comparable to that of an OLED with the major difference
being the presence of a lasing cavity in which the emission layer
will be present. Such a cavity can simply be the space between
anode and cathode, where one of the two will be highly reflective
and the other will allow a small percentage of the light to be
transmitted while the rest will reflect back in the cavity.
DRAWING DESCRIPTION
BRIEF DESCRIPTION OF THE DRAWINGS
[0060] The present invention will become more fully understood from
the detailed description given herein below and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention, and wherein:
[0061] FIG. 1: Scheme of an OLED containing several layers. The
basic structure consists of the anode, cathode and emission layer.
Other layers to facilitate or optimize the device such as a hole
blocking (HBL), electron injecting (EIL), electron transport (ETL),
hole injecting (HIL), hole transporting (HTL) or electron blocking
layer (EBL) can be added to optimize the efficiency. In the device
presented here the emission layer can consist of a pure metal
cluster loaded zeolite film or a dispersion of metal cluster loaded
zeolites in a polymer or low molecular matrix.
[0062] FIG. 2: Emission spectrum of the detected
electroluminescence of the OLED presented in example 3. PVK
emission band is centered around 425 nm, oligo metal cluster
emission is centered around 600 nm.
[0063] FIG. 3: Scheme of a LED containing a crystal or layer of
microporous oligo metal clusters containing material, contacted by
two electrodes.
* * * * *