Patent Description:
The present invention relates to the field of light emitting materials, which emit strongly over the entire visible spectrum, including for example white, orange, green, blue and yellow color, devices made therefrom. Disclosed but not forming part of the invention are methods of making these materials and devices.

One of the well-explored hybrid material families consists of I-VII binary metal halides (e.g. CuI). Most of them are constructed by forming coordinate bonds between neutral inorganic modules of various dimensionality and neutral organic ligands (either aromatic or aliphatic) via an electron lone-pair of N, P or S atom. A wealth of many structure types have been reported, ranging from molecular (0D) species to one-dimensional (1D) chains, and from two-dimensional (2D) layers to extended three-dimensional (3D) networks. Their potential for use as lighting phosphors that are free of rare-earth elements (REEs) has been recognized and systematically evaluated very recently. These studies reveal that structures built on cluster-based CumIm modules (e.g. Cu<NUM>I<NUM> rhomboid dimer or Cu<NUM>I<NUM> cubane tetramer) typically have much higher luminescence efficiency compared to those made of inorganic modules of higher dimensions, such as 1D chain or 2D layer of (CuI)∞. While structures with strong emission and enhanced stability can be achieved by incorporating highly emissive inorganic cores and strong binding ligands to generate extended 1D, 2D and 3D networks, serious limitations remain, for example low blue-light excitability and poor solution processibility, the latter being the common problem for most inorganic materials.

A need thus exists for the design of phosphors with improved chemical and thermal stability, while having strong blue excitability and high processability.

<NPL>) discloses the formation of luminescent structures composed of anionic (CumIm+n)n- clusters and cationic N-ligands, using an all-in-one process.

<NPL>) discloses two types of copper(I) iodides as one-dimensional chained [CuI(bta)] and tetranuclear [(mdabco)<NUM>Cu<NUM>I<NUM>] (mdabco = N-methyl-<NUM>,<NUM>-diazabicyclo[<NUM>,<NUM>,<NUM>]octane), and a method of preparing the same by reacting of N-donor ligands benzotriazole and <NUM>,<NUM>-diazabicyclo[<NUM>,<NUM>,<NUM>]octane with CuI.

<CIT> discloses a method for preparing a sulfur-ether containing metal complex, wherein iodine, metal iodides, an alcohol, and <NUM>-mercaptopyridine are mixed with acetonitrile and react under solvothermal conditions to produce a sulfur-ether compound.

<NPL>) discloses a method for carrying out a simultaneous redox, alkylation, and self-assembly reaction under solvothermal conditions to form a copper(I) chain polymer of luminescent Cu<NUM>I<NUM>- and EtS-<NUM>-C<NUM>H<NUM>N+Et components (Et = CH<NUM>CH<NUM>).

<NPL>) discloses a method for preparing (ipq)<NUM>[(Cu<NUM>I<NUM>)·2I<NUM>] crystals (ipq+ = N-(isopentyl)-quinolinium) by reacting ibq·I, CuI and I<NUM> in DMF.

<NPL>) discloses a method for preparing the coordination polymer [(Cu<NUM>I<NUM>)(BPE)]n (BPE = <NUM>, <NUM>-bis(pyridinium) ethane dication).

<NPL>) discloses a method of preparing a 3D supramolecular compound of the binuclear [Cu<NUM>I<NUM>(Nppch)<NUM>] unit (Nppch = N-(<NUM>-pyridyl) pyridinium chloride hydrochloride) by reacting CuI and KI in DMF/H<NUM>O solution with Nppch in CH<NUM>OH/H<NUM>O solution.

<NPL>) discloses three halogencuprate(I) complexes comprising <NUM>-(trimethylammonio)phenyldisulphide (Tab-Tab): [Tab-Tab][CuX<NUM>] (wherein X=I or X=Br) and {[Tab-Tab][Cu<NUM>I<NUM>]}n and methods for preparing the same by reacting CuX (X=I, Br) with TabHPF<NUM> (Tab=<NUM>-(trimethylammonio)benzenethiolate) under Et<NUM>N or Et<NUM>NI.

<NPL>) discloses a method for preparing CdSe-CuTAPPI composite films on quartz substrate using CdSe nanoparticles and meso-tetra-(<NUM>-trimethylaminophenyl) porphyrin copper iodide(CuTAPPI) molecules as assembly units.

<CIT> discloses inorganic-organic hybrid IB-VII semiconductor compounds, in which a Group IB transition metal halide salt is coordinated with an organic heteroaromatic ligand, wherein at least one ring atom of said heteroaromatic ligand is a heteroatom independently selected from N, O and S and the Group IB metal of the halide salt is coordinated to a ring heteroatom. Also disclosed are semiconductor and light emitting devices comprising these materials, including light emitting diodes, and methods of preparing these materials and devices.

<NPL> discloses examples of small molecules, oligomers and polymers that bear one or multiple pyrimidine rings in their scaffolds and highlights the applications related to their optical properties.

<NPL> discloses developments (from <NUM> to early <NUM>) in coordination chemistry as they relate to luminescence-based chemical sensing are reviewed. In particular, it discloses developments involving assemblies for luminescence-based sensing of metal cations, organic and inorganic anions, small neutral molecules in solution, and various volatile organic chemicals, including: (a) the chemical features that permit the sensors to function selectively, and (b) the mechanistic schemes that permit analyte recognition and binding events to be converted to luminescence responses.

<NPL> discloses the infrared spectra of caffeine and its salts, showing that protonation occurs at position <NUM>, the free nitrogen atom in the imidazole ring.

<CIT> discloses a process for preparing quaternary ammonium compounds, which comprises reacting compounds comprising an sp<NUM>-hybridized nitrogen atom with a dialkyl sulfate or trialkyl phosphate and subjecting the resulting ammonium compound to an anion exchange.

<CIT> discloses an electroluminescent device which includes a first and second electrode with an electroluminescent layer comprising a first and second electroluminescent compound capable of emitting light of a different first and a second color dispersed therebetween. The first electroluminescent compound may be an electroluminescent polymer or low-molecular weight conjugated electroluminescent compound. The second electroluminescent compound is a metal-ion complex, typically mono-kernel or bi-kernel, having one or more ligands, at least one of which is substituted with a conjugated moiety, such as an oligo-phenylenevinylene or an oligo-phenylene derivative.

<CIT> discloses compounds for use in porous films for light extraction and/or light scattering in electronic devices, such as light-emitting devices, such compounds being represented by the formula Rg<NUM>-Rg<NUM>-Rg<NUM>-Rg<NUM>-Rg<NUM>, wherein Rg<NUM> , Rg<NUM> and Rg<NUM> are independently, optionally substituted, pyridinyl, or phenyl, and Rg<NUM> and Rg<NUM> are independently, optionally substituted, benzimidazol-<NUM>-yl, benzooxazol-<NUM>-yl, or benzothiazol-<NUM>-yl.

<NPL> discloses two M-I (M = Cu, Ag) clusters, {[Ce(DMF)<NUM>][Cu<NUM>I<NUM>]·C<NUM>H<NUM>OH}n and {[Co(DMF)<NUM>]<NUM>[Ag<NUM>I<NUM>]<NUM>}. The first of these clusters contains the eight-coordinated cations [Ce(DMF)<NUM>]<NUM>+ and 1D polymeric anionic chain {[Cu<NUM>I<NUM>]<NUM>-}n , which is constructed from [Cu<NUM>I<NUM>]<NUM>- clusters connected with each other through µ <NUM>-I bridges and exhibits a wavy chain structure. Cluster <NUM> consists of the six-coordinated cations [Co(DMF)<NUM>]<NUM>+ and the dimeric anionic cluster ([Ag<NUM>I<NUM>]<NUM>}<NUM>-, which is fabricated by a pair of heptanuclear butterfly-like clusters connected by two Ag-I bridges. Solid-state luminescence properties of clusters <NUM> and <NUM> are also investigated at room temperature.

<NPL> discloses Five new copper(I) iodide coordination polymers, (Cu<NUM>I<NUM>)(Cu<NUM>I<NUM>)[(Cu(Bta)<NUM>]<NUM>-·(DMBta)<NUM>+·(I-)·x(I<NUM>) (x ≈ <NUM>) (<NUM>), [Cu<NUM>I<NUM>(MBta)] (<NUM>), [Cu<NUM>I<NUM>(MTa)] (<NUM>), (Cu<NUM>I<NUM>)[Cu(Ta)<NUM>]-·(DETa)+ (<NUM>), and [Cu<NUM>I(Bta)<NUM>] (<NUM>) (Bta = benzotriazole, DMBta = <NUM>,<NUM>-N-dimethylbenzotriazolium, MBta = <NUM>-N-methylbenzotriazole, MTa = <NUM>-N-methyltriazole, Ta = <NUM>,<NUM>,<NUM>-triazole, DETa = <NUM>,<NUM>-N-diethyltriazolium), prepared by the solvo(hydro)thermal reactions of CuI, KI, and benzotriazole (or <NUM>,<NUM>,<NUM>-triazole) in methanol (or ethanol or water) and their structural characterization.

<NPL> discloses a mixed-metal compound, [Co(phen<NUM>)]<NUM>[Cu<NUM>I<NUM>] (phen = <NUM>,<NUM>-phenanthroline), containing the two copper(I) iodide anionic clusters [Cu<NUM>I<NUM>]<NUM>- and [Cu<NUM>I<NUM>]<NUM>-, which is synthesized solvothermally and structurally characterized by single crystal X-ray diffraction.

<NPL>, discloses a series of hybrid cuprous halides with architectures ranging from one-dimensional (1D) ribbons to two-dimensional (2D) layers. Disclosed compounds include [TM(<NUM>,<NUM>-bipy)<NUM>]Cu<NUM>I<NUM>, where TM = Fe, Co, and Ni, which feature 1D [Cu<NUM>I<NUM>]<NUM>- chains formed by the interconnection of [Cu<NUM>I<NUM>] units via edge-sharing, and [TM(<NUM>,<NUM>-bipy)<NUM>I]<NUM>Cu<NUM>I<NUM> , where TM = Mn, Cu, and Ru in which [Cu<NUM>I<NUM>] units and [Cu<NUM>I<NUM>] dimers are alternately interlinked via edge-sharing to form the 1D [Cu<NUM>I<NUM>]<NUM>- chains. Compounds [Cu(<NUM>,<NUM>-bipy)<NUM>I][(Me)<NUM>-<NUM>,<NUM>-bipy]Cu<NUM>I<NUM>, [Co(<NUM>,<NUM>-bipy)<NUM>]Cu<NUM>Br<NUM>, and K[Mn(<NUM>,<NUM>-bipy)<NUM>]<NUM>Cu<NUM>I<NUM> are also disclosed and their structures identified.

Described herein is a novel class of phosphor compounds that emit light of different colors with high luminescence quantum efficiency. Coupled with improved thermal and chemical stability, the phosphor compounds of the present invention find application in clean and/or renewable energy devices, including but not limited to photovoltaics and solid-state lighting.

An aspect of the invention provides a phosphor cluster compound of CumXm+n(L)n. X is an anion. L is an cationic organic ligand, wherein at least two atoms of the ligand are heteroatoms independently selected from the group consisting of N, O and S, one of the at least two heteroatoms is a positively charged N, and the other is coordinated to Cu. m is an integer selected from the group consisting of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, and n is <NUM>, <NUM>, <NUM>, <NUM> or <NUM>.

Further required features as to the positively | charged N and the other of the at least two atoms coordinating to Cu are defined in claim <NUM>.

The atoms of said compound are arranged to form a network having a 1D, 2D or 3D crystalline lattice structure.

According to the invention, X is a halide. In some embodiments, X is I. In some embodiments, m is selected from the group consisting of <NUM>, <NUM>, <NUM>, <NUM> or <NUM>, and n is <NUM> or <NUM>. In some embodiments, m is <NUM> and n is <NUM>. In some embodiments, m is <NUM>, <NUM> or <NUM>, and n is <NUM>.

In some embodiments, the positively charged N is sp3 hybridized. In some embodiments, <NUM> groups bonding to the positively charged N are independently selected from C<NUM>-C<NUM> alkyls, said alkyls substituted with one or more groups selected from halogen, -OR<NUM>, -SR<NUM>, - C<NUM>-C<NUM>SR<NUM>, -NO<NUM>, -CN and -NRaRb, wherein R<NUM> at each occurrence is independently hydrogen (H) or C<NUM>-C<NUM> alkyl, and Ra and Rb are independently hydrogen or C<NUM>-C<NUM> alkyl.

Also disclosed herein, but not part of the claimed invention are embodiments, where the positively charged N is sp2 hybridized and is a ring atom of an aromatic system. The aromatic system is optionally substituted with one or
more substituents selected from the group consisting of C1-C10 alkyl, halogen, -OR<NUM>, - SR<NUM>, - C<NUM>-C<NUM>SR<NUM>, -NO<NUM>, -CN and -NRaRb, wherein R<NUM> at each occurrence is independently hydrogen (H) or C<NUM>-C<NUM> alkyl, and Ra and Rb are independently hydrogen or C<NUM>-C<NUM> alkyl. In some embodiments, the positively charged N is a ring atom of an optionally substituted pyridine.

The ligand also contain a non-charged heteroatom coordinating to Cu. The heteroatom can be sp2 or sp3 hybridized. In an embodiment of the invention, the non-charged heteroatom is a ring atom of benzotriazole, wherein the benzotriazole is optionally substituted with one or more substituents selected from the group consisting of C1-C10 alkyl, halogen, -OR<NUM>, -SR<NUM>, - C<NUM>-C<NUM>SR<NUM>, -NO<NUM>, -CN and -NRaRb, wherein R<NUM> at each occurrence is independently hydrogen (H) or C<NUM>-C<NUM> alkyl, and Ra and Rb are independently hydrogen or C<NUM>-C<NUM> alkyl.

In some embodiments, the copper is coordinated to no more than <NUM> iodides. In some embodiments, the copper is coordinated to <NUM> iodides.

In some embodiments, the ligand is selected from the group consisting of <NUM>-benzyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium ((bz-ted), <NUM>-(<NUM>-chloropropyl)-<NUM>,<NUM>-diazabi-cyclo[<NUM>. <NUM>]octan-<NUM>-ium ((<NUM>-Cl-pr-ted), <NUM>-propyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium (pr-ted), <NUM>-(<NUM>-bromoethyl)-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium (<NUM>-Br-et-ted), <NUM>-isopropyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium (i-pr-ted), <NUM>-butyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>] octan-<NUM>-ium ((bu-ted), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-trimethylmethanamin-ium (bttmm), N-((<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)methyl)-N,N-dimethyl ethanaminium (btmdme), N-((<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)methyl)-N,N-dibutylbutan-<NUM>-aminium (btmdb), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-trimethylpropan-<NUM>-aminium (bttmp), <NUM>-(<NUM>-benzo[d] [<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-trimethylpentan-<NUM>-aminium (bttmpe), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>] triazol-<NUM>-yl)-N,N,N-triethylethan-<NUM>-aminium (btte), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-trimethylethan-<NUM>-aminium (bttme), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N-ethyl-N,N-dimethylethan-<NUM>-aminium (btedm), N-((<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)methyl)-N,N-dimethylpropan-<NUM>-aminium (btmdp), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-tri-methylbutan-<NUM>-aminium (bttmbu), and <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-tri-methylhexan-<NUM>-aminium (bttmhe).

In some embodiments, the phosphor compound is selected from the group consisting of Cu<NUM>I<NUM>(bz-ted)<NUM>, Cu<NUM>I<NUM>(<NUM>-Cl-pr-ted)<NUM>, Cu<NUM>I<NUM>(pr-ted)<NUM>, Cu<NUM>I<NUM>(<NUM>-Br-et-ted)<NUM>, Cu<NUM>I<NUM>(i-pr-ted)<NUM>, Cu<NUM>I<NUM>(bu-ted)<NUM>, Cu<NUM>I<NUM>(mtp)<NUM>, Cu<NUM>I<NUM>(tpp)<NUM>(bttmm)<NUM>, Cu<NUM>I<NUM>(tpp)<NUM>(btmdme)<NUM>, Cu<NUM>I<NUM>(btmdb)<NUM>, 0D-Cu<NUM>I<NUM>(me-ted)<NUM>, 0D-Cu<NUM>I<NUM>(me-ted)<NUM>, 0D-Cu<NUM>I<NUM>(et-ted)<NUM>, 0D-Cu<NUM>I<NUM>(i-bu-ted)<NUM>, 1D-Cu<NUM>Br<NUM>(bttmp), 1D-Cu<NUM>I<NUM>(bttmpe), 1D-Cu<NUM>I<NUM>(btte), 1D-Cu<NUM>I<NUM>(bttme)<NUM>, 1D-Cu<NUM>I<NUM>(btedm)<NUM>, 1D-Cu<NUM>I<NUM>(btmdp)<NUM>, 1D-Cu<NUM>I<NUM>(bttmbu)<NUM>, and 1D-Cu<NUM>I<NUM>(bttmhe)<NUM>.

Another aspect of the invention provides a light-emitting diode characterized by a die in conductive contact with an anode and a cathode. The die includes the phosphor compound.

Disclosed but not forming part of the invention is a method of emitting a visible light of red, green, yellow, orange, pink, or blue color. The method includes (a) placing a die formed from the phosphor compound of any one of claims <NUM>-<NUM> in conductive contact between an anode and a cathode within a reflective cavity; and (b) passing a current from the anode to the cathode.

Disclosed but not forming part of the invention is a method of preparing the phosphor compound. The method includes (a) providing a compound of CuX, wherein X is a halogen, (b) mixing said CuX with the ligand L in a solution; and (c) isolating said phosphor compound. In some embodiments, the method further includes introducing triphenylphosphine in step (b).

These and other aspects of the present invention will be described in greater detail below.

Various embodiments of the present invention provides a novel class of CuX (e.g. copper(I) halide) based inorganic-organic hybrid structures with excellent luminescence efficiency, structure stability, and solution processability. Compared to the molecular Copper (I) iodide clusters containing monodentate ligand (e.g. pyridine), both the photo and thermal stability of the new structures are significantly improved as a result of incorporating both ionic and coordinate bonds into the same structure.

The unique type of CuX-based hybrid structures include ionic and covalent (coordinate) bonds within a single molecular cluster. This unprecedented "all-in-one" (AIO) approach allows the creation of compounds bearing all three desired features: (i) being chemically and thermally robust (due to enhanced binding strength through two types of bonds); (ii) possessing the highest luminescence efficiency (as a result of inclusion of highly-emissive inorganic cluster core); and (iii) having excellent solution processability (because of their high solubility and/or easy dispersibility in common solvents inherent to their molecular identity).

While the following text may reference or exemplify specific components of a device or a method of utilizing the device, it is not intended to limit the scope of the invention, which is defined by the claims, to such particular references or examples. Various modifications may be made by those skilled in the art, in view of practical and economic considerations, such as the ligand and the method of preparing the compounds of the present disclosure.

The articles "a" and "an" as used herein refers to "one or more" or "at least one," unless otherwise indicated. That is, reference to any element or component of the present invention by the indefinite article "a" or "an" does not exclude the possibility that more than one element or component is present.

The term "about" as used herein refers to the referenced numeric indication plus or minus <NUM>% of that referenced numeric indication.

The term "alkyl" as used herein include straight- and branched-chain monovalent substituents. Examples include methyl, ethyl, propyl, and isopropyl. For example, the C1-C10 or C1-<NUM> alkyl substituent may contain <NUM> to <NUM> carbon atoms such as propyl and hexyl.

The term "heteroaryl"as used herein refers to optionally-substituted aromatic monocyclic and fused bicyclic heterocycles containing one or more heteroatoms selected from N, O and S. non-limiting examples of heteroaryls include benzimidazole, benzisothiazole, benzisoxazole, benzofuran, benzothiazole, benzothiophene, benzotriazole, benzoxazole, carboline, cinnoline, furan, furazan, imidazole, indazole, indole, indolizine, isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole, oxazole, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole, pyridazine, pyridine, pyrimidine, pyrrole, quinazoline, quinoline, quinoxaline, tetrazole, thiadiazole, thiazole, thiophene, triazine, triazole, and N-oxides thereof.

The common features of these AIO compounds are: (i) they are molecular crystals; (ii) the inorganic modules are anionic and the organic ligands are cationic; (iii) the anionic (CumIm+n)n- and the cationic L+ are further connected by dative bonds.

As shown in <FIG> (bottom), a typical AIO structure contains an anionic inorganic module and a cationic organic ligand. The so-formed "ionic pair" is also bonded directly via a coordinate/dative bond between the metal (Cu) and ligand (L), generating an overall charge-neutral molecular complex.

The AIO type structures can be regarded as the combination of two structure types, as shown in <FIG> (upper left and right). In general, the pure ionic structures (no direct Cu-L bonds, "ligand-free", <FIG>, upper right) are thermally more stable than those of neutral species with Cu-L dative bonds (<FIG>, upper left), however, their optical emission is weak, with low luminescence internal quantum yields (IQYs). On the other hand, molecular clusters with Cu-L dative bonds exhibit the highest IQYs.

Suitable cationic ligands having free heteratoms binding sites are designed to build AIO structures. The cationic nature of the ligands will ensure the formation of ionic compounds with anionic inorganic modules, while the free binding sites enable their direct coordination to Cu atoms via dative bonds.

The phosphor cluster compound of the present invention generally has the formula of CumXm+n(L)n. According to the invention, each X anion is coordinated to one or more of the copper atoms. In some embodiments the compound can include two different types of anions. In some embodiments, each X in the compound is independently fluoride, chloride, bromide or iodide. In some embodiments, X is I.

L is a cationic organic ligand having at least two heteroatoms such as N, O, S, and P. According to the invention, the heteroatoms are independently selected from the group consisting of N, O and S. In some embodiments, the ligand is monocationic. One of the heteroatoms is a positively charged N and contributes to the cationic nature of the ligand. Another heteroatom of the ligand is coordinated to Cu. The subscript m is an integer selected from the group consisting of <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM>. The subscript n is <NUM>, <NUM>, <NUM>, <NUM> or <NUM>. In some embodiments, m is <NUM>, <NUM>, <NUM>, <NUM> or <NUM>, and n is <NUM>. In some embodiments, the atoms of the compound are arranged to form a network having a 1D, 2D or 3D crystalline lattice structure.

The ligand contains a neutral heteroatom such as a non-charged N, O or S for coordinating to Cu and a nitrogen cation for pairing with the anionic moiety of the compound. Each of the neutral heteroatom and the nitrogen cation can be independently sp2 or sp3 hybridized.

In some embodiments, the nitrogen cation is sp3 hybridized in the form of a quaternary ammonium cation. The quaternary ammonium cation bears <NUM> substituents which can be same and different and each independently selected from alkyl, aryl, and heteroaryl. In some embodiments, all of the <NUM> carbons connected to the nitrogen cation are aliphatic. In some embodiments, <NUM> or <NUM> groups connected to the nitrogen are independently C1-C10 alkyls, each of the alkyls substituted with one or more groups selected from halogen, -OR<NUM>, -SR<NUM>, - C<NUM>-C<NUM>SR<NUM>, -C<NUM>-C<NUM> alkyl, -NO<NUM>, -CN and -NRaRb, wherein R<NUM> at each occurrence is independently hydrogen (H) or C<NUM>-C<NUM> alkyl, and Ra and Rb are independently hydrogen or C<NUM>-C<NUM> alkyl. Further, one or more carbons in the alkyls can be replaced with a heteroatom such as N, S, and O. In some embodiments, at least three groups of quaternary ammonium cation are alkyl groups independently selected from methyl, ethyl, isopropyl, butyl, said alkyls optionally substituted with one or more hydroxyl, chlorine or bromine.

In some embodiments, the nitrogen cation is sp2 hybridized. In some embodiments, the nitrogen is a ring atom of a heteroary which can be optionally substituted with one or more groups selected from halogen, -OR<NUM>, -SR<NUM>, - C<NUM>-C<NUM>SR<NUM>, -C<NUM>-C<NUM> alkyl, -NO<NUM>, -CN and -NRaRb, wherein R<NUM> at each occurrence is independently hydrogen (H) or C<NUM>-C<NUM> alkyl, and Ra and Rb are independently hydrogen or C<NUM>-C<NUM> alkyl.

The ligand also contains a heteroatom (e.g. N, S, O or P) coordinating to Cu. In some embodiments, the heteroatom is a sp2 or sp3 hybridized nitrogen. In some embodiments, the heteroatom is a sp3 hybridized nitrogen. The three groups connecting to the nitrogen are independently selected from H, alkyl, aryl and heteroaryl.

In some embodiments, the heteroatom coordinating to Cu is a sp2 hybridized nitrogen as a ring atom of an optionally substituted heteroaryl. Non-limiting examples of heteroaryls include benzimidazole, benzisothiazole, benzisoxazole, benzofuran, benzothiazole, benzothiophene, benzotriazole, benzoxazole, carboline, cinnoline, furan, furazan, imidazole, indazole, indole, indolizine, isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole, oxazole, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole, pyridazine, pyridine, pyrimidine, pyrrole, quinazoline, quinoline, quinoxaline, tetrazole, thiadiazole, thiazole, thiophene, triazine, triazole and N-oxides thereof. In some embodiments, the heteroaryl moiety is pyridine or benzotriazole, which are optionally substituted. The optional substituents include one or more substituents selected from the group consisting of C1-C10 alkyl, halogen, -OR<NUM>, -SR<NUM>, -C<NUM>-C<NUM>SR<NUM>, -NO<NUM>, -CN and -NRaRb, wherein R<NUM> at each occurrence is independently hydrogen (H) or C<NUM>-C<NUM> alkyl, and Ra and Rb are independently hydrogen or C<NUM>-C<NUM> alkyl. In some embodiments, the heteroatom coordinating to Cu is a sp2 hybridized nitrogen of benzotriazole.

The positively charged N or the cation-containing heteroaryl and the neutral heteroatom coordinating to Cu can be connected via any type of spacer in the ligand. Examples of the spacer include C<NUM>-<NUM> alkyl, aryl, heteroaryl, and any combination thereof.

Examples of the ligand include <NUM>-benzyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium ((bz-ted), <NUM>-(<NUM>-chloropropyl)-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium ((<NUM>-Cl-pr-ted), <NUM>-propyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium (pr-ted), <NUM>-(<NUM>-bromoethyl)-<NUM>,<NUM>-diazabicyclo [<NUM>. <NUM>]octan-<NUM>-ium (<NUM>-Br-et-ted), <NUM>-isopropyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium (i-pr-ted), <NUM>-butyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium ((bu-ted), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-trimethylmethanaminium (bttmm), N-((<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl) methyl)-N,N-dimethyl ethanaminium (btmdme), N-((<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)methyl)-N,N-dibutylbutan-<NUM>-aminium (btmdb), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-trimethylpropan-<NUM>-aminium (bttmp), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-trimethylpentan-<NUM>-aminium (bttmpe), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-triethyl-ethan-<NUM>-aminium (btte), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-trimethylethan-<NUM>-aminium (bttme), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N-ethyl-N,N-dimethylethan-<NUM>-aminium (btedm), N-((<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)methyl)-N,N-dimethylpropan-<NUM>-aminium (btmdp), <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-trimethylbutan-<NUM>-aminium (bttmbu), and <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-trimethylhexan-<NUM>-aminium (bttmhe).

The copper can be in a +<NUM> or +<NUM> oxidation state. In some embodiments, the oxidation state of Cu is +<NUM> and the halogen is iodide. The excess halide coordinating to Cu leads to an anionic moiety of the compound. Each Cu can be coordinated to <NUM>, <NUM> or <NUM> halides. In some embodiments, Cu is coordinated to only three halides or iodides. This unsaturated state of Cu represents a unique property of the phosphor compounds and allows it to coordinate to a ligand described herein. In some embodiments, m is selected from <NUM>, <NUM>, <NUM>, <NUM> or <NUM>, and n is <NUM>. Exemplary compounds of the present invention includes Cu<NUM>I<NUM>(bz-ted)<NUM>, Cu<NUM>I<NUM>(<NUM>-Cl-pr-ted)<NUM>, Cu4I6(pr-ted)<NUM>, Cu<NUM>I<NUM>(<NUM>-Br-et-ted)<NUM>, Cu<NUM>I<NUM>(i-pr-ted)<NUM>, Cu<NUM>I<NUM>(bu-ted)<NUM>, Cu<NUM>I<NUM>(mtp)<NUM>, Cu<NUM>I<NUM>(tpp)<NUM>(bttmm)<NUM>, Cu<NUM>I<NUM>(tpp)<NUM>(btmdme)<NUM>, Cu<NUM>I<NUM>(btmdb)<NUM>, 0D-Cu<NUM>I<NUM>(me-ted)<NUM>0D-Cu<NUM>I<NUM>(me-ted)<NUM>, 0D-Cu<NUM>I<NUM>(et-ted)<NUM>, 0D-Cu<NUM>I<NUM>(i-bu-ted)<NUM>, 1D-Cu<NUM>Br<NUM>(bttmp), 1D-Cu<NUM>I<NUM>(bttmpe), 1D-Cu<NUM>I<NUM>(btte), 1D-Cu<NUM>I<NUM>(bttme)<NUM>, 1D-Cu<NUM>I<NUM>(btedm)<NUM>, 1D-Cu<NUM>I<NUM>(btmdp)<NUM>, 1D-Cu<NUM>I<NUM>(bttmbu)<NUM>, 1D-Cu<NUM>I<NUM>(bttmhe)<NUM>,.

Under excitation of a suitable wavelength, the compounds of the present invention emit light of various colors as shown in <FIG>. Accordingly, the compounds of the present invention can be configured into structures that are useful in the fabrication of electrical and optical devices by conventional means well known to those of ordinary skill in the art. For example, the compounds of the present invention can be manufactured into structures that function as quantum dots, quantum wells and quantum wires. Generally speaking, the compounds of the present invention find application in devices where the quantum confined structures are useful. These include, but are not limited, to interlayer dielectric devices in microelectronics, thermo-electric devices for cooling, beating and generating electricity, and quantum well laser structures useful in optoelectric devices for the generation or modulation of light radiation, including the modulation of light radiation for the transmission of information. The compounds of the present invent-tion can also be used in infra-red photodetectors, lasers for spectroscopic and fiber optic applications, electroluminescent lasers and electronic phosphors. In particular, the compounds can be used in light-emitting devices to generate direct light of various colors.

Light emitting diodes (LEDs) based on the phosphor compounds of the present invention are prepared by substituting the phosphor compounds of the present invention for the phosphors conventionally used in the LED. That is, a chip (blue or UV or near UV) coated by the phosphors of the present invention is placed in conductive contact between an anode and a cathode within a reflective cavity. When the anode has a voltage that is more positive than its cathode by at least the LED's forward voltage drop, current flows. The phosphors absorb blue or UV or near-UV light and convert it to lower energy emission (e.g. yellow, orange or white light).

By changing the compound or adjusting the exciting wavelength, different light with emits black, red, green, yellow, orange, pink, gold or blue color is emitted. The phosphor compound displays intense luminescence with internal quantum yields (IQYs) greater than <NUM>%, <NUM>%, <NUM>% or <NUM>%.

A further aspect of the disclosure not forming part of the invention provides a method of preparing the phosphor compound. The method includes (a) providing a compound of CuX, wherein X is an anion (e.g. a halide), (b) mixing said CuX with the ligand L in a solution; and (c) isolating said phosphor compound. In some embodiments, the method further includes introducing triphenylphosphine in step (b). X and L are as defined above.

CuI (<NUM> %, Alfa Aesar); bulk methanol (<NUM> %, Alfa Aesar); dichloromethane (<NUM>+ %, Alfa Aesar); <NUM>-mercaptopyridine (><NUM>%, Alfa Aesar); N,N-dimethylethylamine (<NUM>%, Sigma Aldrich); trimethylamine (<NUM>% w/w aq. , Alfa Aesar); formaldehyde (<NUM>% in aq. , Alfa Aesar); thionyl chloride (<NUM> %, Alfa Aesar); tributylamine (><NUM> %, Alfa Aesar); <NUM>,<NUM>'-dipyridyl disulfide (<NUM>%, TCI); <NUM>,<NUM>-di-azabicyclo[<NUM>. <NUM>]octane (><NUM>%, TCI); benzimidazole (<NUM>%, Alfa Aesar); <NUM>-iodopropane (<NUM>+%, Alfa Aesar); <NUM>-iodobutane (<NUM>%, Alfa Aesar); <NUM>-chloro-<NUM>-iodopropane (><NUM>%, Alfa Aesar); <NUM>-bromo-<NUM>-iodoethane (<NUM>%, Sigma Aldrich); <NUM>-iodopropane (><NUM>%, Alfa Aesar); benzyl bromide (><NUM>%, TCI); sodium salicylate (<NUM>%, Merck), YAG:Ce3+ type <NUM> (Global Tungsten & Powders Corp), PolyOx N750 (Dow Chemical).

Single crystal X-ray diffraction (SCXRD). Single crystal data of <NUM>-<NUM> were collected on a D8 goniostat equipped with a Bruker PHOTON100 CMOS detector at the Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, using synchrotron radiation. The structures were solved by direct methods and refined by full-matrix least-squares on F2 using the Bruker SHELXTL package. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www. uk/data_request/cif. The structures were deposited in Cambridge Structural Database (CSD) with numbers: <NUM>, <NUM>-<NUM>.

Powder X-ray diffraction (PXRD) analysis. Powder X-ray diffraction (PXRD) analyses were carried out on a Rigaku Ultima-IV unit using Cu Kα radiation (λ = <NUM>Å). The data were collected at room temperature in a 2θ range of <NUM>-<NUM>° with a scan speed of <NUM> °/min. The operating power was <NUM> kV/<NUM> mA.

Thermogravimetric analysis. Thermogravimetric analyses (TGA) of samples were performed using the TA Instrument Q5000IR thermal gravimetric analyzer with nitrogen flow and sample purge rate at <NUM>/min and <NUM>/min respectively. About <NUM> of samples were loaded onto a platinum sample pan and heated from room temperature to <NUM> at a rate of <NUM>/min under nitrogen flow.

Room-temperature Photoluminescence measurements. Photoluminescence (PL) measurements were carried out on a Varian Cary Eclipse spectrophotometer. Powder samples were evenly distributed and sandwiched between two glass slides (which do not have emission in the visible range) for room temperature measurements.

Temperature dependent photoluminescence spectroscopy and lifetime measurements. Pressed pellets of <NUM> to <NUM> thickness were prepared in a <NUM> diameter die with the pressure of approximately <NUM> psi (<NUM> bar). The pellets were sandwiched between two pieces of cover glass using a non-fluorescent double-sided tape (Bazic Product, permanent double-sided tape), and were mounted on the sample holder of a cryostat (Cryo Industries of America, Inc. , Model 6NSVT Variable Temperature Optical Top-Loading Nitrogen Cryostat). A Cryo-con 32B Temperature Controller was used to precisely control the temperature of the sample chamber. An excitation wavelength of <NUM> (Spectra-Physics MaiTai BB Ti:Sapphire laser (pulse width < <NUM> ps) with a frequency doubler) was used for all compounds. The laser repetition rate was set to <NUM> or <NUM>. The emission collected from the sample by a convex lens was separated and redirected by a <NUM>/<NUM> beam splitter. Half of the emission was collimated into a multimode optical fiber which is connected to a spectrometer for photoluminescence spectroscopy measurements. Another half of the collected emission went through a <NUM> ± <NUM> band-pass filter to an APD detector for luminescence decay measurements. The decay data were recorded by TimeHarp <NUM> Nano (PicoQuant) with <NUM> or <NUM> ns resolution. The photoluminescence lifetimes of the different compounds at different temperatures were extracted by fitting the photoluminescence decay curves in OriginPro <NUM> with first- or second-order exponential decay functions with coefficient of determination (R2) values larger than <NUM>.

Diffuse reflectance spectroscopy. Optical absorption spectra were measured at room temperature on a Shimadzu UV-<NUM> UV/VIS/NIR spectrometer. The reflectance data were converted to Kubelka-Munk function, α/S = (<NUM>-R)<NUM>/2R (α is absorption coefficient, S is scattering coefficient and R is reflectance), and used to estimate the bandgap. The scattering coefficient (S) was treated as a constant as the average particle size of the samples used in the measurements was significantly larger than <NUM>. Samples for reflectance measurements were prepared by evenly distributing ground powder sample between two quartz slides.

Internal quantum yield measurements. Internal quantum yield (IQY) measurements were made on C9920-<NUM> absolute quantum yield measurement system (Hamamatsu Photonics) with <NUM> W xenon monochromatic light source and <NUM> inch (<NUM>) integrating sphere. Samples for internal quantum yield measurements were prepared by
spreading fine powder samples evenly on the bottom of a quartz sample holder. Sodium salicylate (SS) and YAG:Ce3+ were chosen as the standards with reported IQY values of <NUM>% and <NUM>% at an excitation energy of <NUM> and <NUM>, respectively. Their IQY values were measured to be <NUM>% and <NUM>%, respectively and corrections were made based on the reported data.

Film preparation. Compound <NUM> (<NUM>) was dissolved in DMF (<NUM>) and sonicated for <NUM> to form a clear yellow solution. The solution was filtered through a polyvinylidene fluoride (PVDF) microfiltration membrane (<NUM>) before use. The solution was then spin-coated onto a glass substrate (pre-heated to <NUM> to promote the removal of the solvent) with a speed of <NUM> rpm for <NUM> seconds, and the spin coating procedure was repeated for <NUM> times, followed by a thermal annealing at <NUM> for <NUM>.

Film characterization. The continuity of the film was characterized by reflection-mode bright-field (BF) optical microscopy (Nikon Optiphot <NUM>) (Fig. 5b). Dark-field (DF) reflection images were acquired to study the roughness of the film and the images were also obtained through optical microscopy but in dark-field mode. A 75W Xenon bulb was used as the illumination source. The BF scattering image was collected using 100x bright-field objectives and set to a color CCD camera using the exposure time <NUM>, gain <NUM> and <NUM>% saturation. PXRD pattern was taken directly of the film with the glass substrate. Surface morphology and thickness of the films were investigated on an atomic force microscope (AFM) in Nanoscope IV (Digital Instruments) in tapping mode (standard cantilevers with spring constant of 40N/m and tip curvature <<NUM>) with a scan speed of <NUM>/s.

Design and fabrication of prototype LED bulbs. Selected phosphors were dispersed in binder/ethanol solution, and were uniformly coated on to glass bulbs. The bulbs were placed on top of LED lamps with UV chips (<NUM> V, <NUM> W, <NUM>) as the excitation source. For white light bulbs, blue light chip (<NUM> V, <NUM> W, <NUM>) was used.

Cationic N/S-ligands were synthesized by alkylation of tertiary amine group of selected ligands via Menshutkin reactions. Three types of synthetic approaches (I, II and III) as shown in more details below were designed, from which ten cationic ligands were prepared, including one formed in-situ. Direct reactions of the ligands with CuI led to the formation of ten new AIO type compounds. In some cases, triphenylphosphine (tpp) was also introduced as terminal ligands to prevent formation of high dimensional inorganic modules such as chains or layers. All compounds are molecular species containing inorganic clusters of various compositions (<FIG>) with the following formulae: Cu<NUM>I<NUM>(L1)<NUM> (<NUM>), Cu<NUM>I<NUM>(L2)<NUM> (<NUM>), Cu<NUM>I<NUM>(L3)<NUM> (<NUM>), Cu<NUM>I<NUM>(L4)<NUM> (<NUM>), Cu<NUM>I<NUM>(L5)<NUM> (<NUM>), Cu<NUM>I<NUM>(L6)<NUM> (<NUM>), Cu<NUM>I<NUM>(L7)<NUM> (<NUM>), Cu<NUM>I<NUM>(tpp)<NUM>(L8)<NUM> (<NUM>), Cu<NUM>I<NUM>(tpp)<NUM>(L9)<NUM> (<NUM>), and Cu<NUM>I<NUM>(L10)<NUM> (<NUM>). Ligand synthesis and characterizations.

General design of ligand synthesis. Three types of reactions were planned to synthesize cationic ligands. In Reaction I alkalation occurs at one of the tertiary N site of a bidentate N-ligand (e.g. triethylenediamine). The unalkylated N atom serves as binding site for Cu metal. In reaction II, alkylation takes place at the aromatic N while S atom acts as a binding site for Cu. While these reactions involve a single step. Reaction III is a two-step process, where alkylation happens at the NH site of an N-heterocyclic ring, making aromatic N atom available for binding to Cu metal center. Bidentate triethylenediamine (ted), <NUM>-mercaptopyridine (<NUM>-SH-py), and benzotriazole (bta) derivatives were selected as starting ligands for route I, II and III, respectively.

Synthetic approach I, II and III used to prepare cationic ligands with free binding sites marked in bold. <CHM>
<CHM>
<CHM>.

Selected cationic organic ligands were prepared (L1 - L10 of <FIG>) following reported procedures with some modifications.

Preparation of <NUM>-benzyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium (bz-ted, L1). Ted (<NUM>, <NUM> mmol) was first dissolved in acetone (<NUM>) upon sonication and benzyl bromide (<NUM>, <NUM> mmol) was added dropwise into it under magnetic stirring. The solution remained clear after the mixing and white precipitate formed in a few hours. The precipitate was collected by filtration, washed with ethyl acetate, and dried under vacuum. The yield was <NUM>%.

Preparation of <NUM>-(<NUM>-chloropropyl)-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium (<NUM>-Cl-pr-ted, L2). Ted (<NUM>, <NUM> mmol) was dissolved in acetone (<NUM>) upon sonication and <NUM>-chloro-<NUM>-iodopropane (<NUM>, <NUM> mmol) was added slowly in it under magnetic stirring. The solution was stirred for two hours and the white precipitate formed was collected by filtration, washed with ethyl acetate and dried under vacuum. Yield was <NUM>%.

Preparation of <NUM>-propyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium (pr-ted, L3). Ted (<NUM>, <NUM> mmol) was first dissolved in acetone (<NUM>) upon sonication and <NUM>-iodopropane (<NUM>, <NUM> mmol) was added dropwise into it under magnetic stirring. The solution remained clear after the mixing and white precipitate formed in an hour. The precipitate was collected by filtration, washed with ethyl acetate, and dried under vacuum. The yield was <NUM>%.

Preparation of <NUM>-(<NUM>-bromoethyl)-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium (<NUM>-Br-et-ted, L4). <NUM>-Bromo-<NUM>-iodoethane (<NUM>, <NUM> mmol) was added dropwise into acetone (<NUM>) containing ted (<NUM>, <NUM> mmol) under magnetic stirring. White precipitate formed in a few hours, and the precipitate was collected by filtration, washed with ethyl acetate, and dried under vacuum. The yield was <NUM>%.

Preparation of <NUM>-isopropyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium (i-pr-ted, L5). Ted (<NUM>, <NUM> mmol) was first dissolved in acetone (<NUM>) upon sonication and <NUM>-iodopropane (<NUM>, <NUM> mmol) was added dropwise into it under magnetic stirring. The white precipitate formed in one day. The precipitate was collected by filtration, washed with ethyl acetate, and dried under vacuum. The yield was <NUM>%.

Preparation of <NUM>-butyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octan-<NUM>-ium (bu-ted, L6). Ted (<NUM>, <NUM> mmol) was first dissolved in acetone (<NUM>) upon sonication and <NUM>-iodobutane (<NUM>, <NUM> mmol) was added dropwise into it under magnetic stirring. White precipitate formed within an hour. The precipitate was collected by filtration, washed with ethyl acetate, and dried under vacuum. The yield was <NUM>%.

Preparation of (<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)methanol (btm). A mixture of bta (<NUM>, <NUM> mol), distilled water (<NUM>), and formaldehyde solution (<NUM>%, <NUM>) was first refluxed for <NUM> hours. After cooling to room temperature, the resulting white precipitate was collected by filtration, washed with water and dried under vacuum to give the corresponding <NUM>-benzotriazol-<NUM>-yl-methanol (btm).

Preparation of <NUM>-(chloromethyl)-<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazole (Cl-mbt). Btm (<NUM>, <NUM> mol) was dissolved in a mixture of CH2Cl2 (<NUM>) and dimethylformamide (DMF) (<NUM>) and thionyl chloride (<NUM>) in methylene chloride (<NUM>) was added dropwise into it under magnetic stirring at room temperature. The reaction mixture was kept stirring for <NUM> at room temperature, then its pH was adjusted by NaHCO3 saturated solution to <NUM>. The organic layer was separated and was evaporated under reduced pressure, giving white crystalline powder as <NUM>-(chloromethyl)-<NUM>-benzotriazole (Cl-mbt).

Preparation of <NUM>-(<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)-N,N,N-trimethylmethan-aminium (bttmm, L8). Cl-mbt (<NUM>, <NUM> mol) was then fully dissolved in acetone (<NUM>) and KI (<NUM>) was added. The reaction mixture was kept under stirring for <NUM> before the solution was filtered. The filtrate was then added with trimethylamine (<NUM>) and precipitate was formed after stirring at room temperature overnight. The white precipitate was filtered, washed with acetone and dried under vacuum as the final product.

Preparation of N-((<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)methyl)-N,N-dimethyl ethanaminium (btmdme, L9). Cl-mbt (<NUM>, <NUM> mol) was first dissolved in acetone (<NUM>) and KI (<NUM>) was added. The reaction mixture was kept under stirring for <NUM> and the solution was filtered. The filtrate was added with N,N-dimethylethylamine (<NUM>) and precipitate formed after stirring at room temperature overnight. The white precipitate was filtered, washed with acetone and dried under vacuum as the final product.

Preparation of N-((<NUM>-benzo[d][<NUM>,<NUM>,<NUM>]triazol-<NUM>-yl)methyl)-N,N-dibutylbutan-<NUM>-aminium (btmdb, L10). Cl-mbt (<NUM>, <NUM> mol) was first dissolved in acetone (<NUM>) and KI (<NUM>) was added. The reaction mixture was kept under stirring for <NUM> before the solution was filtered. The filtrate was added with tributylamine (<NUM>) and the precipitate was formed after stirring at room temperature overnight. The white precipitate was filtered, washed with acetone and dried under vacuum as the final product.

Crystallographic data, crystal images, structural plots and synthetic procedures of compounds <NUM>-<NUM> are summarized in Tables <NUM> and <NUM>.

Synthesis of <NUM>. CuI (<NUM>, <NUM> mmol) was first dissolved in KI saturated solution (<NUM>) in a reaction vial. Acetonitrile (<NUM>) was added as another layer and then the ligand (1mmol) in methanol (<NUM>) was added slowly in to the vial. The reaction mixture was kept undisturbed at room temperature, and rod-shaped single crystals formed in one day and were collected by filtration.

Synthesis of <NUM>. Acetonitrile (<NUM>) was added into KI saturated solution (<NUM>) containing CuI (<NUM>, <NUM> mmol), and then the ligand (<NUM> mmol) in methanol (<NUM>) was slowly added. Rod-shaped single crystals formed in one day and collected by filtration.

Synthesis of <NUM>. Plate like crystals of <NUM> were prepared similarly as that of <NUM>. Pure phase of powder samples could be synthesized by direct mixing of CuI in acetonitrile with ligand in methanol. Precipitate formed immediately and was collected by filtration.

Synthesis of <NUM>. Compound <NUM> were prepared similarly as that of <NUM>. Rod-shaped crystals were formed in <NUM> days and were collected by filtration.

Synthesis of <NUM>. Compound <NUM> was prepared in the same way as that of <NUM>. Rod like single crystals formed in <NUM> days.

Synthesis of <NUM>. Compound <NUM> was synthesized by the method similar as that of <NUM>. Plate-shaped colorless single crystals could be obtained in <NUM> day.

Synthesis of <NUM>. Compound <NUM> was prepared by the solvothermal reaction of CuI, KI, <NUM>-mercaptopyridine and methanol in a molar ratio of <NUM>:<NUM>:<NUM>:<NUM>:<NUM> at <NUM> for <NUM>. pH of the reaction mixture were adjusted by <NUM> of HCl to <NUM>. Large amount of yellowish crystalline powder of <NUM> with the yield of <NUM>% was generated. Rod-shaped crystals suitable for single-crystal X-ray analyses were together with the powder and were separated for structure determination.

Synthesis of <NUM>. 0D-Cu2I2(tpp)<NUM> (<NUM>) was first well dispersed in a mixture of toluene (<NUM>) and CH2Cl2 (<NUM>), and then was mixed with the ligand (<NUM>) in methanol (<NUM>). The mixture was heated at <NUM> for <NUM> days, which afforded greenish crystalline powder along with plate-shaped single crystals.

Synthesis of <NUM>. Yellowish rock shaped single crystals were obtained under the similar condition as that of <NUM>.

Synthesis of <NUM>. Saturated KI solution (<NUM>) containing CuI (<NUM>, <NUM> mmol) was mixed with methanol (<NUM>) containing the ligand (<NUM> mmol). Then acetone (<NUM>) was added and the reaction mixture was kept in the open air for the solvent to slowly evaporate. Yellowish rhombohedral-shaped single crystals formed in <NUM> days and were collected by filtration.

DFT calculations on selective AIO type compounds.

DFT calculations were performed to optimize the geometries and calculate the optical band gaps and density of states of the AIO type compounds <NUM>, <NUM>, <NUM> and <NUM>, with initial geometries obtained from experimental crystal structures. The systems have periodic structures and each structure has between <NUM> and <NUM> atoms in the primitive cell. We adopted the PBE0 functional, the PBE norm-conserving pseudopotentials and a Plane-Wave basis set for the calculations using the Quantum Espresso software package. The PBE0 hybrid functional was used because the LDA or GGA functionals alone underestimates the band gaps. We used <NUM> Ry for the plane-wave kinetic energy cutoff, and found that increasing the cutoff by <NUM> to <NUM> times only changes the calculated band gaps by < <NUM>. 01eV for all the AIO type compounds studied. For geometry optimizations, a quasi-Newton algorithm was used with a convergence threshold of <NUM>-<NUM> Ry/Bohr, and the Brillouin-zone integration was sampled with T (gamma) k-points with a Gaussian broadening of <NUM> Ry.

The calculated band gaps for the four AIO type compounds are listed in Table <NUM>, along with the experimentally estimated values. The calculations correctly captured the trend that compounds in sub-group I have higher band gaps than those in sub-group II, although the calculated values are systematically lower than experiment by about <NUM> eV. This error range is consistent with recent calculations on a series of semiconductors and insulators using hybrid functionals. The main contributions from the atomic orbitals to the valence band maximum (VBM) and the conduction band minimum (CDM) are shown in Table <NUM> and <NUM>, respectively.

New AIO structures with the general formula of 0D-CumIm+n(L)n (L = cationic organic ligand) were thus synthesized and structurally characterized. Crystal structure analysis reveals that direct coordinate/dative bonds are formed between the free binding atom (either N or S) of the cationic ligand and Cu atom of the anionic cluster for all <NUM> structures. Based on the types of binding atoms these compounds can be categorized into two sub-groups. For sub-group I compounds (<NUM>-<NUM>) the N atom directly bonded to metal has a sp<NUM> electron configuration (part of the aliphatic ring), whereas the coordinating N atom of the ligands in sub-group II compounds (<NUM>-<NUM>) has a sp<NUM> configuration (part of the aromatic ring, Table <NUM>). The S atom in compound <NUM> does not belong to a ring. It is included in sub-group II based on its similar emission behavior to sub-group II members.

Different from molecular crystals made of neutral inorganic modules, which are limited to a small group of clusters such as CuI monomers, Cu2I2 dimers, or Cu4I4 tetramers, a large variety of anionic inorganic modules can be obtained using similar ligands, offering a remarkably rich structural variation for this type of compounds. Among <NUM> structures included here, <NUM> different clusteres are identified, from dimer (Cu2) to hexamer (Cu6), most of which are discovered for the first time (<FIG>). In addition, some of them have the same composition but are structurally different, adding yet another degree of diversity towards this family. For example, compounds <NUM>, <NUM>, and <NUM> all contain (Cu4I6)<NUM>-, but their structures are very different (<FIG>). Structures with identical inorganic modules but coordinated to different ligands have also been obtained, such as <NUM> and <NUM>; <NUM> and <NUM>; and <NUM> and <NUM>. Different from neutral molecular species where each Cu atom has tetrahedral coordination and bonds to at least one ligand molecule, some Cu atoms in ionic compounds are coordinated only to three iodine. The unsaturated coordination of Cu atoms is a unique property of this family.

All of these structures display intense luminescence with internal quantum yields (IQYs) greater than <NUM>%. Some are as high as <NUM>% (Table <NUM>). The previously reported ted based "ligand-free" ionic structures, on the other hand, are all poor emitters. Cu<NUM>I<NUM>(di-et-ted)<NUM> (di-et-ted = <NUM>,<NUM>-diethyl-<NUM>,<NUM>-diazabicyclo[<NUM>. <NUM>]octane-<NUM>,<NUM>-diium), for example, gives a very weak yellow-orange emission (<FIG>) with a IQY (<NUM>%) that is incomparably lower. Such differences suggest that metal-ligand bonds play a vital role in the electron transfer process upon excitation of these compounds.

It is also interesting to note the similarities and differences in the optical behavior of the compounds in two sub-groups: While all of them emit at similar energies (green to yellow region) and have a broad single emission band at room temperature (<FIG> and <FIG>), the optical band gaps of sub-group I compounds are considerably higher than those of the sub-group II compounds (Table <NUM>, Inset of <FIG> and <FIG>). Clearly, photoluminescence (PL) of sub-group I does not correlate with their optical band gaps (<FIG>), which is similar to that of Cu<NUM>I<NUM> cubane based structures. Like most of the cubane structures, the sub-group I compounds also have short Cu-Cu distances (less than <NUM>Å, Table <NUM>), suggesting that they may follow the same emission mechanism. Sub-group II compounds, on the other hand, have emission energies close to their estimated optical band gaps (<FIG>), resembling those of Cu<NUM>I<NUM>(L)m dimer- and 1D-CuI(L) chain-based structures. The Cu-Cu ditances are generally longer in these compounds (with the exception of <NUM>).

All members of this sub-group can be effectively excited by blue light, an important requirement for phosphors that can be used in conjunction with a blue LED chip in commercial WLED bulbs/lamps. Among them, compound <NUM> has a IQY of <NUM>% under <NUM> excitation, comparing favorably to that of a benchmark yellow phosphor YAG:Ce<NUM>+.

The sub-group I compounds exhibit thermochromic behavior, as illustrated in <FIG>. For compound <NUM>, lowering temperature results in a small blue shift in its PL accompanied by a peak width narrowing. This behavior can be attributed to reduced structural torsion at low temperatures and increased localization of the excited state on the molecular structure. On the other hand, sub-group II compounds do not show clear thermochromism. There is very little temperature dependence in their emission energies (<FIG>). The PL lifetimes of sub-group I compounds (e.g. <NUM> and <NUM>) show very little or no dependence on temperature, which is characteristic of phosphorescence (Tables <NUM> - <NUM>). Their PL lifetime decay curves are best fit with a single exponential decay function (Tables <NUM> - <NUM>) with an average amplitude-weighted PL lifetime decay constant (τ) of about <NUM> (<FIG>).

For sub-group II compounds (e.g. <NUM> and <NUM>), however, the PL lifetimes have strong temperature dependence (<FIG>), with τ values decreasing from <NUM>-<NUM> at <NUM> to <NUM>-<NUM> at <NUM> (Tables S6-S7). Their PL lifetime decay curves are best fit by a double exponential decay function indicating that two separate processes may be contributing to the emission (Tables <NUM>-<NUM>). For compound <NUM>, as temperature increases there is generally an increase in the fraction of the short lifetime decay constant, τ<NUM>, and at <NUM>, almost <NUM>% of the PL lifetime decay is attributed to a relatively fast <NUM> ns component. This suggests that in addition to phosphorescence (~<NUM>%), a substantial fraction of the emission at room temperature originates from thermally-activated delayed fluorescence (TADF) (<FIG>, Table <NUM>). TADF has been observed previously in organic-inorganic hybrid materials and is associated with small singlet to triplet energy differences (<FIG>) allowing exchange of electrons between the lowest excited triplet state (T<NUM>) and the lowest excited singlet state (S1) prior to radiative recombination.

The lack of emission peak shifts with increasing temperature is also consistent with TADF and a small energy difference between S<NUM> and T<NUM>. On the other hand, the absence of TADF for compound <NUM> (and other sub-group I compounds) is attributed to a large energy separation between S<NUM> and T<NUM> excited states which inhibits reverse intersystem crossing (RISC, <FIG>). This large energy difference is due to a higher lying S<NUM> state compared to sub-group II compounds and is consistent with the generally higher optical band gaps or shorter wavelength (higher energy) absorption onset observed in the optical absorption spectra of sub-group I compounds (Table <NUM>, <FIG>).

Density functional theory (DFT) calculations were performed on selected structures from sub-group I (compounds <NUM> and <NUM>) and sub-group II (compounds <NUM> and <NUM>). The calculations correctly capture the experimental observation that optical band gaps of sub-group I are significantly larger than those of sub-group II (<FIG>, Table <NUM>). The valence bands of all four compounds share common features - the primarily contributions are from the inorganic components (Cu 3d and I 5p atomic orbitals, Table <NUM>). However the contributions to the conduction bands are very different for compounds from the two sub-groups. For sub-group I compounds, they are mainly from Cu and I atomic orbitals (Cu 3d and I 5p, Table <NUM>), supporting a "cluster-centered" (CC) charge transfer mechanism for the observed luminescence. For sub-group II compounds, they are mostly from organic ligands (C 2p and N 2p atomic orbitals, Table <NUM>), and therefore, the emission is largely due to a metal-to-ligand charge transfer (MLCT) and iodine-to-ligand charge transfer (XLCT).

The greatly enhanced thermal stability of these AIO structures is reflected from thermogravimetric (TG) analysis of these compounds. The decomposition temperatures of sub-group I compounds are as high as <NUM>. Most sub-group II compounds are stable up to <NUM>. Compared to CumIm-based charge-neutral molecular clusters, which generally decompose below <NUM>, the addition of ionic bonding stabilizes AIO structures by at least <NUM>. To further evaluate their suitability as lighting phosphors, <NUM> and <NUM> were selected for long-term photo- and thermal-stability tests. After heating the selected samples at <NUM> for <NUM> days without protection, their IQY values were maintained at > <NUM>% compared to the initial values (<FIG>). Similarly, nominal decreases in their IQYs were detected after continuous UV irradiation on these samples for <NUM> days (Inset of <FIG>). The two reference materials, namely 0D-Cu<NUM>I<NUM>(py)<NUM> dimer and 0D-Cu<NUM>I<NUM>(py)<NUM> tetramer, however, suffered nearly <NUM>% drop in their IQYs upon heating for merely one day, and their IQYs were reduced by ~<NUM>% and ~<NUM>% at the end of the photostability experiment.

Another advantage of these molecular clusters is their excellent solubility and dispersibility in common organic solvents, including chloroform, dimethylformamide (DMF), dimethyl sulfoxide (DMSO) (Fig 5a). This makes it possible to fabricate films by solution-based process. High quality, continuous films of <NUM> were made by spin coating followed by thermal annealing. The film samples were characterized by optical microscope (Fig 5b), powder X-ray diffraction (PXRD) analysis and atomic force microscopy (AFM) (Fig 5c). Prototype LED bulbs using these materials as phosphors were assembled by remote model (Fig. 5d). The white-emitting bulb was generated by coating <NUM> on a commercial blue LED. High solution processability allows easy coating of the phosphors onto various substrates, including flexible papers or fabric. Compared to other three sub-classes that we have developed so far, the AIO family is the only one that meets all four standards essential for lighting phosphors: optical tunability, high quantum efficiency, excellent thermal and photo stability and solution processability (Table <NUM>).

Additional compounds are summarized in Table <NUM>. Besides the different colors resulting from unique ligands, the compounds also exhibit high thermal stability.

Claim 1:
A phosphor compound of CumXm+n(L)n wherein:
X is a halide,
L is a cationic organic ligand, wherein at least two atoms of the ligand are heteroatoms independently selected from the group consisting of N, O and S, one of the at least two atoms is positively charged N and the other of the at least two atoms is coordinated to Cu,
m is an integer selected from the group consisting of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>,
n is an integer selected from the group consisting of <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>; and wherein:
a) the positively charged N is sp3 hybridized and is bonded to at least three groups independently selected from C1-C10 alkyls, said alkyls substituted with one or more groups selected from halogen, -OR<NUM>, -SR<NUM>, -C<NUM>-C<NUM>SR<NUM>, -NO<NUM>, -CN and -NRaRb, wherein R<NUM> at each occurrence is independently hydrogen (H) or C<NUM>-C<NUM> alkyl, and Ra and Rb are independently hydrogen or C<NUM>-C<NUM> alkyl, wherein the other of the at least two atoms is sp<NUM> hybridized N and coordinates to Cu; or
b) the other of the at least two atoms is a ring atom of benzotriazole, said benzotriazole optionally substituted with one or more substituents selected from the group consisting of C1-C10 alkyl, halogen, -OR<NUM>, -SR<NUM>, -C<NUM>-C<NUM>SR<NUM>, -NO<NUM>, -CN and -NRaRb, wherein R<NUM> at each occurrence is independently hydrogen (H) or C<NUM>-C<NUM> alkyl, and Ra and Rb are independently hydrogen or C<NUM>-C<NUM> alkyl.