TWI808948B - Quantum dot light emitting devices - Google Patents

Abstract

The present invention provides a quantum dot light emitting diode comprising i) an emitting layer of at least one semiconductor nanoparticle made from semiconductor materials selected from the group consisting of Group II-VI compounds, Group II-V compounds, Group III-VI compounds, Group III-V compounds, Group IV-VI compounds, Group I-III-VI compounds, Group II-IV-VI compounds, Group II-IV-V compounds, or any combination thereof; and ii) a polymer for hole injection or hole transport layer; and the polymer comprises, as polymerized units, at least one or more monomers having a first monomer structure comprising a) a polymerizable group, b) an electroactive group with formula NAr¹ Ar² Ar³ wherein Ar¹ , Ar² and Ar³ independently are C₆ -C₅₀ aromatic substituents, and (c) a linker group connecting the polymerizable group and the electroactive group.

Description

quantum dot light emitting device

The invention relates to an electronic device, in particular, a quantum dot light-emitting diode.

Quantum dot light emitting diodes (QLEDs) are electroluminescent devices that use multiple organic and inorganic layers combined with an emissive layer of semiconductor nanoparticles, sometimes referred to as quantum dots (QDs). The quantum dot layer in a QLED is capable of emitting light when an electrical input is applied to the device. Therefore, QLEDs can be used as light sources in displays and general lighting applications. One limitation of QLEDs is the lack of a suitable hole transport layer (HTL) that enables efficient charge injection into the quantum dot layer. Poor charge injection into quantum dots results in QLED devices with high operating voltage and low light generation efficiency.

Therefore, there is a continuing need for new hole transport materials to enable improved QLED devices with high brightness and color purity, minimized power consumption, and high reliability.

The present invention provides a quantum dot light-emitting diode, which includes: i) a compound selected from group II-VI compounds, group II-V compounds, group III-VI compounds, group III-V compounds, group IV -At least one semiconductor nanometer made of a group of semiconductor materials consisting of Group VI compounds, Group I-III-VI compounds, Group II-IV-VI compounds, Group II-IV-V compounds, or any combination thereof and ii) a polymer for the hole injection or hole transport layer; and said polymer comprises at least one or more monomers having a first monomer structure comprising as Polymerization unit: a) a polymerizable group, b) an electroactive group having the formula NAr ¹ Ar ² Ar ³ , wherein Ar ¹ , Ar ² and Ar ³ are independently C ₆ to C ₅₀ aromatic substituents, and (c) a linker group connecting the polymerizable group and the electroactive group.

The quantum dot light-emitting device of the present invention includes an anode layer, one or more hole injection layers, one or more hole transport layers, one or more electron blocking layers, an emissive layer, one or more Hole blocking layers, optionally one or more electron transport layers, optionally one or more electron injection layers and a cathode.

The light emissive layer includes at least one semiconductor nanoparticle.

The hole injection layer or the hole transport layer or both the hole injection layer and the hole transport layer or the layer acting as either/both the hole injection layer or/and the hole transport layer comprises the polymers described below. light emitting layer

The light-emitting layer of the QLED includes semiconductor nanoparticles. In some embodiments, semiconductor nanoparticles may include elemental, binary, ternary, or quaternary semiconductors. Semiconductors may include 5 or more elements if desired. In some embodiments, the composition of semiconductor nanoparticles may comprise Group IV compounds, Group II-VI compounds, Group II-V compounds, Group III-VI compounds, Group III-V compounds, Group IV compounds - a Group VI compound, a Group I-III-VI compound, a Group II-IV-VI compound, a Group II-IV-V compound, or any combination thereof. In some embodiments, the composition of semiconductor nanoparticles may include metal oxides such as ZnO and TiO ₂ . In some embodiments, the composition of semiconductor nanoparticles may include a perovskite material such as methylammonium lead trihalide. In some embodiments, the semiconductor nanoparticles may comprise CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, InP, _CuInSe2, or any combination thereof. In some embodiments, semiconductor nanoparticles can include heterojunctions. In some embodiments, the semiconductor nanoparticles may comprise a graded composition whereby the composition transitions over a distance from a first composition to a second composition.

The semiconductor nanoparticles can be undoped; or doped with rare earth elements, such as, Eu, Er, Tb, Tm, Dy; and/or doped with transition metal elements, such as, Mn, Cu and Ag; or any combination thereof .

In some embodiments, the semiconductor nanoparticles have at least one dimension - 100 nm or less in length, 50 nm or less in length, or even 20 nm or less in length. In some embodiments, the semiconductor nanoparticles in the light emitting layer may have a distribution in size. In some embodiments, the size distribution of the semiconductor nanoparticles can be unimodal or multimodal. In some embodiments, semiconductor nanoparticles have isotropic dimensions or non-isotropic dimensions.

In some embodiments, the semiconductor nanoparticles may have a core-shell structure whereby additional material (referred to as the "shell") is coated on the outside of the inner portion of the semiconductor nanoparticles. The shell can consist of a semiconductor or an insulator. In some embodiments, the composition of the shell may include Group IV compounds, Group II-VI compounds, Group II-V compounds, Group III-VI compounds, Group III-V compounds, Group IV-VI compounds Compounds, Group I-III-VI compounds, Group II-IV-VI compounds, Group II-IV-V compounds, or any combination thereof. In further embodiments, the composition of the shell may include metal oxides such as ZnO and _TiO2 . In another embodiment, the composition of the shell may include a perovskite material such as methylammonium lead trihalide. In some embodiments, the composition of the shell can include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, InP, CuInSe2, or any combination thereof. In some embodiments, the shell may comprise a single layer or multiple layers. In some embodiments, the shell may comprise a graded composition whereby the composition transitions over a distance from a first composition to a second composition. In some embodiments, the composition can be continuously graded from the inner portion of the semiconductor nanoparticles to the shell. In some embodiments, the shell may have a thickness of 100 nm or less, 50 nm or less, or even 5 nm or less.

The surface of semiconductor nanoparticles can be filled with molecules (sometimes referred to as ligands, such as alkylphosphines, alkylphosphine oxides, amines, carboxylic acids, and/or capped inorganic molecules) to allow Dispersion in various solvents and control of aggregation and coalescence of nanoparticles.

Ligand molecules can be covalently or non-covalently attached to the quantum dots via functional groups capable of covalent or non-covalent interactions with the outermost layer of the quantum dots. In some embodiments, the functional group can be selected from a list including, but not limited to, phosphine, phosphine oxide, carboxylic acid, amine, and alcohol. In some embodiments, a second functional group may be present on the ligand such that the first functional group interacts with the surface of the quantum dot and the second functional group interacts with the ligand on an adjacent quantum dot.

In some embodiments, the functional groups on the ligand molecule may have organic substituents, such as (but not limited to), saturated alkyl, unsaturated alkyl, aryl, linear alkyl, non-linear alkyl, branched Alkyl, ether or amine groups. In some embodiments, the ligand layer may consist of a mixture of one or more types of molecules. According to embodiments of the present invention, the ligand layer may have any desired thickness. In some embodiments, the ligand layer has a thickness of 15 nm or less, or 10 nm or less, or even 3 nm or less. In some embodiments, the ligand molecules form a complete monolayer or sub-monolayer on the surface of the quantum dot.

In some embodiments, semiconductor nanoparticles can be one-dimensional. The one-dimensional nanoparticles have a cross-sectional area with a characteristic thickness dimension (e.g., the diameter of a circular cross-sectional area or the diagonal of a square or rectangular cross-sectional area) from 1 nm to 1000 nanometers (nm) in diameter, Preferably 2 nm to 50 nm, and more preferably 5 nm to 20 nm (such as about 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20nm). Nanorods are rigid rods with circular cross-sectional areas, with characteristic dimensions within the above-mentioned ranges. The nanowires or nanowhiskers are curved and have various snake-like or worm-like shapes. Nanoribbons have a cross-sectional area bounded by four or five linear sides. Examples of such cross-sectional areas are square, rectangular, parallelepiped, rhombohedral and the like. The nanotube has a substantially concentric hole that traverses the entire length of the nanorod, thereby giving it a tubular shape. The aspect ratio of the one-dimensional nanoparticles is greater than or equal to 2, preferably greater than or equal to 5, and more preferably greater than or equal to 10.

The one-dimensional nanoparticles have a length of 10 to 100 nm, preferably 12 to 50 nm, and more preferably 14 to 30 nm. One-dimensional nanoparticles may have a diameter of 2 to 10 nm, preferably 3 to 7 nm. The one-dimensional nanoparticles have an aspect ratio greater than or equal to about 2, preferably greater than or equal to about 4.

In an exemplary embodiment, the semiconductor nanoparticle comprises a one-dimensional nanoparticle that has been disposed at either or each end of a single endcap or a plurality of endcaps contacting the one-dimensional nanoparticle. In one embodiment, the end caps also touch each other. The end caps are used to passivate the one-dimensional nanoparticles. Nanoparticles can be symmetric or asymmetric about at least one axis. Nanoparticles may be asymmetric in composition, in the composition of the end caps, in geometric structure and electronic structure, or both.

In one embodiment, the nanoparticles comprise one-dimensional nanoparticles comprising end caps at each opposing end along its longitudinal axis. Each end cap has a different composition, thus providing multiple heterojunctions to the nanoparticles. In another embodiment, the nanoparticle comprises a one-dimensional nanoparticle comprising an end cap at each opposite end along its longitudinal axis and further comprising a cap disposed on the one-dimensional nanoparticle. Nodes on radial surfaces or end caps of nanoparticles. The radial surface is also referred to as the side surface of the rod. The end caps may have similar or different compositions to each other, and/or the nodes may have similar or different compositions to each other, so long as one of the end caps has a different composition than at least one of the other end cap or the node.

In one embodiment, the plurality of end caps includes a first end cap and a second end cap partially or completely surrounding the first end cap. The end caps are three-dimensional nanoparticles, at least one of which directly contacts the one-dimensional nanoparticles. Each end cap may or may not be in contact with the one-dimensional nanoparticles. The first end cap and the second end cap may have mutually different compositions. Nodes are also three-dimensional nanoparticles that can be smaller or larger in size than the end caps.

The term "heterojunction" implies having one semiconductor material in direct contact with another semiconductor material.

Each of the one-dimensional nanoparticle, the first end cap and the second end cap includes a semiconductor. The interface between the nanorod and the first end cap provides a first heterojunction, and the interface between the first end cap and the second end cap provides a second heterojunction. In this way, nanoparticles can include a plurality of heterojunctions.

In one embodiment, the heterojunction of the one-dimensional nanoparticle contacting the first endcap has a type I or quasi-type II band alignment. In another embodiment, the point where the second end cap contacts the first end cap has a Type I or quasi-Type II band alignment.

The first endcap and the second endcap are chemically different from each other and are selected from the group consisting of Si, Ge, Pb, SiGe, ZnO, _TiO2 , ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, CdTe , MgO, MgS, MgSe, MgTe, HgO, HgS, HgSe, HgTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, TlN, TIP, TlA, TlSb, TlSb , PbS, PbSe, PbTe, or the like, or a combination comprising at least one of the foregoing semiconductors. In an exemplary embodiment, the first end cap is CdTe or CdSe and the second end cap is ZnSe.

By changing the composition and size (diameter or length) of the one-dimensional nanoparticles, the first endcap and/or the second endcap, the energy bandgap and frequency band shift can be varied. Varying the energy bandgap can be used to alter the wavelength, efficiency and intensity of light generation in nanoparticles. In one embodiment, the conduction band offset between the first endcap and the one-dimensional nanoparticle is much higher than the conduction band offset between the first endcap and the second endcap, and wherein the first endcap The valence band offset between the one-dimensional nanoparticles is much lower than the valence band offset between the first endcap and the second endcap. In another embodiment, the conduction band shift between the first end cap and the one-dimensional nanoparticle is much lower than the conduction band shift between the first end cap and the second end cap, and wherein the first end The valence band offset between the cap and the one-dimensional nanoparticle is much lower than the valence band offset between the first end cap and the second end cap. In yet another embodiment, one of the two heterojunctions formed by the first end cap has a smaller conduction band shift and a larger valence band shift than the other, and the other has a larger conduction band shift. Band shift and smaller valence band shift.

In one embodiment, the nanoparticle includes two types of heterojunctions, where type II interleaved band offsets allow efficient injection of electrons and holes, and type I offsets define recombination centers for efficient light emission.

In one embodiment, nanoparticles can be used to form layers or films. In one embodiment, the layers may be disordered. In another embodiment, the layer may have liquid crystal properties. In another embodiment, a layer may contain ordering in a single dimension. In another embodiment, a layer may contain an order in two dimensions or in three dimensions. In another embodiment, the nanoparticles can self-assemble into a lattice within the film.

In some embodiments, anisotropic nanoparticles can be aligned in layers within the device. In one embodiment, the anisotropic nanoparticles can be aligned such that a one-dimensional axis of the particles is normal to the surface of the layer. In another embodiment, the anisotropic nanoparticles can be aligned within the plan view of the layer. In another embodiment, the anisotropic particles can be aligned such that the one-dimensional axes of the plurality of anisotropic particles are aligned in the same direction. Polymers for hole injection/transport layer

In an exemplary embodiment, the polymer comprises at least one or more monomers as polymerized units having a first monomer structure comprising: a) a polymerizable group, b) an electroactive group having the formula NAr ¹ Ar ² Ar ³ , wherein Ar ¹ , Ar ² and Ar ³ are independently C ₆ to C ₅₀ aromatic substituents, and (c) a linker group whose link can be Polymeric groups and electroactive groups.

In another embodiment, the polymer additionally includes at least one or more monomers having a second monomeric structure.

The polymer has a Mw of at least 5,000, preferably at least 10,000, preferably at least 20,000; preferably not greater than 10,000,000, preferably not greater than 1,000,000, preferably not greater than 500,000, preferably not greater than 400,000 , preferably not greater than 300,000, preferably not greater than 200,000, preferably not greater than 100,000. Preferably, the polymer comprises at least 50% (preferably at least 60%, preferably at least 70%, preferably at least 80%, preferably at least 90%) electroactive groups containing at least five aromatic Rings, preferably at least six, preferably not more than 20, preferably not more than 15; other monomers not having this property may also be present. A cyclic moiety containing two or more fused rings is considered a single aromatic ring, provided that all ring atoms in the cyclic moiety are part of the aromatic system. For example, naphthyl, carbazolyl, and indolyl are considered to have a single aromatic ring, but fenyl is considered to contain two aromatic rings because the carbon atom at the 9-position of fenene is not part of an aromatic system. Preferably, the polymer comprises at least 50%, preferably at least 70%, electroactive groups containing at least one.

The polymerizable groups of the present invention may be selected from vinyl groups (preferably attached to aromatic rings), benzocyclobutene, acrylate or methacrylate groups, trifluoroethylene ethers, cinnamate/challe Ketones, dienes, ethoxyacetylenes and 3-ethoxy-4-methylcyclobut-2-enone. Preferred polymerizable groups include at least one of the following structures. Wherein "R ₁ to R ₁₂ " groups are independently hydrogen, deuterium, C ₁ to C ₃₀ alkyl, heteroatom substituted C ₁ to C ₃₀ alkyl, C ₁ to C ₃₀ aryl, heteroatom substituted C ₁ to C ₃₀ aryl, or represent another part of the resin structure; preferably, hydrogen, deuterium, C ₁ to C ₂₀ alkyl, heteroatom substituted C ₁ to C ₂₀ alkyl, C ₁ to C ₂₀ aryl , heteroatom substituted C ₁ to C ₂₀ aryl group, or another part of the resin structure; preferably, hydrogen, deuterium, C ₁ to C ₁₀ alkyl, heteroatom substituted C ₁ to C ₁₀ alkyl, C ₁ to C ₁₀ aryl, heteroatom substituted C ₁ to C ₁₀ aryl, or another part of the resin structure; preferably, hydrogen, deuterium, C ₁ to C ₄ alkyl, heteroatom substituted C ₁ to C ₄ alkyl, or represent another part of the resin structure. In a preferred embodiment of the present invention, the "R ₁ to R ₁₂ " groups can be connected to form a fused ring structure.

In yet another embodiment, examples of polymerizable groups include: .

Preferably, the polymerizable group is selected from .

In one embodiment, the electroactive group of the present invention has the formula NAr ¹ Ar ² Ar ³ , wherein Ar ¹ , Ar ² and Ar ³ are independently C ₆ to C ₅₀ aromatic substituents.

Suitable examples of Ar ¹ to Ar ³ include .

Preferably, the electroactive group of formula NAr ¹ Ar ² Ar ³ contains a total of 4 to 20 aromatic rings; preferably at least 5, preferably at least 6; preferably no more than 18, preferably There are no more than 15, preferably no more than 13. Preferably, each of Ar ¹ , Ar ² and Ar ³ independently contains at least 10 carbon atoms, preferably at least 12; preferably not more than 45, preferably not more than 42 , preferably not more than 40. In a preferred embodiment, each of ^Ar2 and ^Ar3 independently contains at least 10 carbon atoms, preferably at least 15, preferably at least 20; preferably no more than 45, Preferably no more than 42, preferably no more than 40; and Ar ¹ contains no more than 35 carbon atoms, preferably no more than 25, preferably no more than 15. The total number of carbon atoms in the Ar substituent includes aliphatic carbon atoms, for example, C ₁ to C ₆ hydrocarbyl substituents or non-aromatic ring carbon atoms (for example, 9 carbons of fennel). The Ar group may contain heteroatoms, preferably, N, O or S; preferably, N; preferably, the Ar group does not contain heteroatoms other than nitrogen. Preferably, only one linker group is present in the compound of formula NAr ¹ Ar ² Ar ³ . Preferably, the Ar group includes one or more of biphenyl, fenyl, phenylene, carbazolyl and indolyl.

When one of ^the nitrogen atoms in one of ^the Ar substituents is a ^triarylamine nitrogen atom, Ar ¹ , Ar ² and Ar ³ groups. In this case, the nitrogen atom and the Ar group should be construed so as to satisfy the claim limitations.

Preferably, Ar ¹ , Ar ² and Ar ³ collectively contain no more than five nitrogen atoms, preferably no more than four, preferably no more than three.

Suitable examples of electroactive groups having the formula NAr ¹ Ar ² Ar ³ include the following: .

In another embodiment, the polymer includes a second monomer selected from the list below. .

Preferably, the polymer comprises less than 50% of the second monomer, preferably less than 40%, preferably less than 30%, preferably less than 20%, preferably less than 10%.

The second monomer has a Mw of less than 5,000, preferably less than 3,000, preferably less than 2,000 and preferably less than 1,000.

The polymerizable group and the electroactive group of the present invention are linked via a linker group selected from the group consisting of: a covalent bond; -O-; -alkylene-; -arylylene-;- Alkylene-arylylene-;-Arylylene-Alkylene-;-O-Alkylene-;-O-Arylylene-; Alkylene-O-; -O-Alkylene-O-Alkylene-O-; -O-Arylylene-O-; (CH ₂ CH ₂ -O) _n -, wherein n is an integer from 2 to 20; -O-alkylene-O-alkylene-; -O-alkylene-O-arylylene-;- O-arylylene-O-; -O-arylylene-O-alkylene-; and -O-arylylene-O-arylylene.

In one embodiment, the linker group is an aryloxy linker having at least one benzyl carbon attached to an oxygen atom. Preferably, the aryloxy linker is an ether, ester or benzyl alcohol. Preferably, the aryloxy linker has two benzyl carbon atoms attached to the oxygen atom. A benzyl carbon atom is a carbon atom that is not part of an aromatic ring and is attached to a ring carbon of an aromatic ring having from 5 to 30 carbon atoms (preferably 5 to 20), preferably a benzene ring. In another embodiment, the linker group is an alkyl, aryl, heteroalkyl, heteroaryl linker attached to a vinyl group.

In one embodiment, the linker group comprises a structure selected from the list below. .

Optionally, the polymer may further comprise a p-type dopant, which may be an organic Brynsted acid with pKa ≤ 4; a Lewis acid comprising positive aromatic ions and anions; or a thermal acid generator (TAG), which is Ammonium or pyridinium salts of organic brenest acids having a pKa ≤ 2 or esters of organic sulfonic acids.

In one embodiment, the organic Brenest acid has a pKa ≤ 2, preferably ≤ 0. Preferably, the organic Brenest acid is an aromatic, alkyl or perfluoroalkyl sulfonic acid; a carboxylic acid; a protonated ether; or a compound of the formula Ar ₄ SO ₃ CH ₂ Ar ₅ , wherein Ar ₄ is phenyl, Alkylphenyl or trifluoromethylphenyl, and Ar ₅ is nitrophenyl.

In one embodiment, the positive aromatic ion has from seven to fifty carbon atoms, preferably seven to forty. In a preferred embodiment, the positive aromatic ion is an onium ion or has the formula Ions of , where A is a substituent on one or more of the aromatic rings and is H, D, CN, CF ₃ or (Ph) ₃ C+ (attached via Ph); X is C, Si, Ge or Sn . Preferably, X is C. Preferably, A is the same on all three rings.

In one embodiment, the anion is of the formula A tetraaryl borate, wherein R represents zero to five non-hydrogen substituents selected from F and CF ₃ . Preferably, R represents five substituents on each of the four rings, preferably five fluoro substituents.

Preferably, acid catalysts for use in the present invention include Brenest acid, Lewis acid or TAG selected from the list below. In one embodiment, the TAG has a degradation temperature < 280°C. .

Especially preferred TAG is an organic ammonium salt, preferably a pyridinium salt selected from the list below. .

Optionally, the polymer may be further blended with one or more p-type dopants selected from neutral and ionic compounds comprising trityl salts, ammonium salts, iodide salts, onium ionic salts, imidazolium Salts, phosphonium salts, oxonium salts and mixtures thereof. Preferably, the ionic compound is selected from trityl borate, ammonium borate, iodine borate, onium borate, imidazolium borate, phosphonium borate, oxonium borate and mixtures thereof. Suitable examples of p-type dopants used in the present invention include the following compounds (p-1) to (p-15): .

Preferably, the p-type dopant is the following compound (p-1): .

The p-type dopant is 1% by weight or more, 3% by weight or more, 5% by weight or more or even 7% by weight or more based on the total weight of the polymer and At the same time an amount of 20% by weight or less, 15% by weight or less, 12% by weight or less or even 10% by weight or less is present in the present invention.

Optionally, p-type dopants may be present as a separate layer. Without being limited by theory, p-type dopants may diffuse into the polymer after deposition of the polymer. Optionally, the diffusion of p-type dopants can be accelerated by heat treatment.

When preparing a solution for coating a polymer on a substrate, preferably the solvent has at least 99.8% by weight, preferably A purity of at least 99.9% by weight. Preferably, the solvent has a RED value (relative energy difference (relative to polymer) as calculated from Hansen solubility parameter using CHEMCOMP v2.8.50223.1) of less than 1.2, more preferably less than 1.0. Preferred solvents include aromatic hydrocarbons and aromatic-aliphatic ethers, preferably those having six to twenty carbon atoms. Anisole, mesitylene, xylene and toluene are especially preferred solvents.

Preferably, the polymer of the invention is present as a thin layer on the substrate. Preferably, the thickness of the polymer film produced according to the present invention is from 1 nm to 100 microns, preferably at least 10 nm, preferably at least 30 nm, preferably not more than 10 microns, preferably not more than 1 Micron, preferably not greater than 300 nm.

The polymers of the present invention can be deposited by any of various types of solution processing techniques known or proposed for the fabrication of organic electronic devices. For example, the polymer can be deposited using a printing process such as inkjet printing, nozzle printing, lithography, transfer printing or screen printing, or for example using a coating process such as spray coating, spin coating or dip coating solution. After solution deposition, the solvent is removed, which can be performed using conventional methods such as vacuum drying and/or heating. The film is preferably formed on the substrate by a solution process, preferably by spin coating or by an inkjet process.

When films have been produced by spin coating, the spin coating film thickness is primarily determined by the solids content in the solution and the spin rate. For example, solutions formulated with 2, 5, 8 and 10 wt% polymer yielded film thicknesses of 30, 90, 160 and 220 nm, respectively, at a spin rate of 2000 rpm.

The polymer layer formed by coating the polymer composition on the surface can be baked at a temperature from 50°C to 150°C (preferably, 80°C to 120°C), preferably for less than five minutes , followed by at a temperature from 120°C to 280°C (preferably at least 140°C, preferably at least 160°C, preferably at least 170°C; preferably not greater than 230°C, preferably not greater than 215°C ) thermally crosslinked. Preferably, the wet film shrinks by 5% or less after baking and annealing. Preferably, the duration of exposure to the heated atmosphere is 2 minutes or longer; more preferably 5 minutes or longer. Preferably, the atmosphere is inert; more preferably, the atmosphere contains 1% by weight oxygen or less; more preferably, the atmosphere contains 99% by weight or more nitrogen.

The thin polymer layers can be further crosslinked. Crosslinking can be performed by exposing the layer solution to heat and/or actinic radiation, including UV light, gamma rays or x-rays. Crosslinking can be performed in the presence of initiators that decompose under heat or radiation to generate free radicals or ions that initiate the crosslinking reaction. Crosslinking can be performed in situ during fabrication of the device. After crosslinking, the polymeric layer produced therefrom is preferably free of residual parts that are reactive or decompose by exposure to light, positive charges, negative charges or excitons.

Preferably, the polymer layer is resistant to dissolution by solvents (solvent resistance is sometimes referred to as "solvent orthogonality"). Solvent resistance is useful because after fabrication of a QLED layer containing the polymer composition of the present invention, Subsequent layers can be applied to the layer containing the composition of the present invention. In many cases, the subsequent layer will be applied by solution processing. It is required that the solvent in the subsequent solution processing does not dissolve or significantly degrade the layer containing the composition of the present invention • The process of solution deposition and crosslinking can be repeated to create multiple layers.

When the composition of the invention is present in a HTL, preferably the HTL will be formed by solution processing. Subsequent layers may be applied to the HIL; subsequent layers are typically emissive layers. If the subsequent layer is applied by a solution process, preferably the HTL is resistant to being dissolved in the solvent used to apply the subsequent layer in the solution process.

An exemplary organic electronic device includes semiconductor nanoparticles as an emissive layer in the device. The device includes a substrate, a first electrode, a hole injection layer, a hole transport layer (as disclosed herein), nanoparticles, an electron transport layer, and a second electrode. The substrate typically comprises an optically clear, electrically insulating glass, or an optically clear, electrically insulating polymer. The first electrode may include an optically transparent conductive polymer or metal oxide. Examples of the first electrode are indium tin oxide, tin oxide, thin films of polypyrrole, polyaniline, polythiophene or the like. A suitable hole injection material for use in the hole injection layer is PEDOT:PSS (poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate), which is two ionomers The polymer mix. The electron transport layer includes zinc oxide or titanium oxide nanoparticles. The second electrode (which acts as a cathode) includes a metal film, an example of which is an aluminum film. Other materials can be used for the first electrode, hole injection layer, In the electron transport layer and the second electrode.

In an embodiment, the display device can be a pixelated light-emitting diode, which can emit light of a single color (single wavelength) or light of a plurality of colors (light of different wavelengths). For example, it can emit white light, or it can emit red, green and blue light that can be combined to produce white light. The articles can be used to generate light throughout the visible light spectrum.

In an embodiment, a display device may have a color converting layer. The color conversion layer can include periodic nanospheres, which help extract confined light in the device, and also increase the effective light path for more efficient color conversion.

The materials disclosed herein can be used in flat, curved, and transparent displays, and in multilayer displays.

The materials disclosed herein can be used as lighting, such as white lighting, red lighting, conformal light coating, color-tuned lighting, lighting for signage, or the like. example

The following examples illustrate embodiments of the invention. All parts and percentages are by weight unless otherwise indicated.

All solvents and reagents are available from commercial vendors (eg, Sigma-Aldrich, TCI, and Alfa Aesar) and are used in the highest available purity and/or if necessary, recrystallized prior to use. Anhydrous solvents were obtained from an internal purification/distribution system (hexane, toluene, and tetrahydrofuran) or purchased from Sigma-Aldrich. All experiments involving "water-sensitive compounds" were performed in "oven-dried" glassware under a nitrogen atmosphere or in a glove box.

The following standard analytical equipment and methods were used in the Examples. Gel Permeation Chromatography ( GPC )

The molecular weight of the polymer was analyzed using gel permeation chromatography (GPC). Dissolve 2 mg of HTL polymer in 1 mL of THF. The solution was filtered through a 0.20 μm polytetrafluoroethylene (PTFE) syringe filter, and 50 μl of the filtrate was injected onto the GPC system. The following analytical conditions were used: Pump: Waters™ e2695 separation module at a nominal flow rate of 1.0 mL/min; Eluent: Fisher Scientific HPLC grade THF (stable); Injector: Waters e2695 separation module; Column: Two 5 µm Mixed-C columns from Polymer Laboratories Inc. maintained at 40°C; detector: Shodex RI-201 differential refractive index (DRI) detector; calibration: 17 polystyrene standard materials, From Polymer Laboratories Inc., a polynomial curve of order 3 fitted over the range of 3742 kg kg/mol to 0.58 kg/mol. Nuclear Magnetic Resonance ( NMR )

^1H -NMR spectra (500 MHz or 400 MHz) were acquired on a Varian VNMRS-500 or VNMRS-400 spectrometer at 30 °C. Chemical shifts are referenced to tetramethylsilane (TMS) (6:000) in CDCl ₃ . Liquid Chromatography Mass Method ( LC/MS )

Routine liquid chromatography/mass spectrometry (LC/MS) studies were performed as follows. A one microliter aliquot of the sample (as a 1 mg/ml solution in tetrahydrofuran (THF)) was injected into an Agilent 6520 quadrupole time-of-flight (Q-TOF) coupled via a dual electrospray interface (ESI) operating in PI mode. Agilent 1200SL binary liquid chromatography (LC) of MS system. The following analysis conditions were used: column: Agilent Eclipse XDB-C18, 4.6*50 mm, 1.7 μm; column oven temperature: 30°C; solvent A: THF; solvent B: 0.1% formic acid in water/acetonitrile (v/v, 95/5); gradient: 40-80% solvent A in 0-6 min, hold 9 min; flow: 0.3 mL/min; UV detector: diode array, 254 nm; MS conditions: capillary Voltage: 3900 kV (negative), 3500 kV (positive); Mode: negative and positive; Scan: 100-2000 amu; Rate: 1 sec/scan; Desolvation temperature: 300°C. Synthesis of HTL1 Monomer

4-(3-(4-([1,1'- biphenyl ]-4- yl (9,9- dimethyl -9H- fenest -2- yl ) amino ) phenyl )-9H- carbazole Synthesis of -9- yl ) benzaldehyde : N- (4-(9H-carbazol-3-yl)phenyl)-N-([1,1'-biphenyl]-4-yl)-9, 9-Dimethyl-9H-tertilene-2-amine (2.00 g, 3.318 mmol, 1.0 equiv), 4-bromobenzaldehyde (0.737 g, 3.982 mmol, 1.2 equiv), CuI (0.126 g, 0.664 mmol, 0.2 equiv ), potassium carbonate (1.376 g, 9.954 mmol, 3.0 eq) and 18-crown-6 (86 mg, 10 mol%) filled the round bottom flask. The flask was flushed with nitrogen and connected to a reflux condenser. 10.0 mL of dry degassed 1,2-dichlorobenzene was added, and the mixture was refluxed for 48 hours. The cooled solution was quenched with saturated aqueous _NH4Cl and extracted with dichloromethane. The combined organic fractions were dried and the solvent was removed by distillation. The crude residue was purified by silica gel chromatography (hexane/chloroform gradient) and the product was obtained as a bright yellow solid (2.04 g). The product has the following properties: ¹ H-NMR (500 MHz, CDCl ₃ ): δ 10.13 (s, 1 H), 8.37 (d, J = 2.0 Hz, 1 H), 8.20 (dd, J = 7.7, 1.0 Hz, 1 H), 8.16 (d, J = 8.2 Hz, 2 H), 7.83 (d, J = 8.1 Hz, 2 H), 7.73 to 7.59 (m, 7 H), 7.59 to 7.50 (m, 4 H) , 7.50 to 7.39 (m, 4 H), 7.39 to 7.24 (m, 10 H), 7.19 to 7.12 (m, 1 H), 1.47 (s, 6H). ¹³ C-NMR (126 MHz, CDCl ₃ ): δ 190.95, 155.17, 153.57, 147.21, 146.98, 146.69, 143.38, 140.60, 140.48, 139.28, 138.93, 135.90, 135.18, 134.64, 1 34.46, 133.88, 131.43, 128.76, 127.97 , 127.81, 126.99, 126.84, 126.73, 126.65, 126.54, 126.47, 125.44, 124.56, 124.44, 124.12, 123.98, 123.63, 122.49, 120.96, 120.70, 120.57, 1 19.47, 118.92, 118.48, 110.05, 109.92, 46.90, 27.13.

(4-(3-(4-([1,1'- biphenyl ]-4- yl (9,9- dimethyl -9H- fen -2- yl ) amino ) phenyl )-9H- carba Synthesis of azol -9- yl ) phenyl ) methanol : Fill a round bottom flask with formula 1 (4.36 g, 6.17 mmol, 1.00 equiv) under nitrogen blanket. The material was dissolved in 40 mL of 1:1 THF:EtOH. Borohydride (0.28 g, 7.41 mmol, 1.20 equiv) was added in portions, and the material was stirred for 3 hours. The reaction mixture was cautiously quenched with 1 M HCl, and the product was partially extracted with dichloromethane. The combined org. fractions were washed with saturated aqueous sodium bicarbonate, dried over _MgSO4 and concentrated to a crude residue. The material was purified by chromatography (hexane/dichloromethane gradient) and the product was obtained as a white solid (3.79 g). The product has the following properties: ¹ H-NMR (500 MHz, CDCl ₃ ): δ 8.35 (s, 1 H), 8.19 (dt, J = 7.8, 1.1 Hz, 1 H), 7.73-7.56 (m, 11 H) , 7.57-7.48 (m, 2 H), 7.48-7.37 (m, 6 H), 7.36-7.23 (m, 9 H), 7.14 (s, 1 H), 4.84 (s, 2 H), 1.45 (s , 6H). ¹³ C-NMR (126 MHz, CDCl ₃ ): δ 155.13, 153.56, 147.24, 147.02, 146.44, 141.27, 140.60, 140.11, 140.07, 138.94, 136.99, 136.33, 135.06, 134.35, 132.96, 128.73, 128.44, 127.96, 127.76 ,127.09,126.96,126.79,126.62,126.48,126.10,125.15,124.52,123.90,123.54,123.49,122.46,120.66,120.36,120.06,119.43,118.82,1 18.33, 109.95, 109.85, 64.86, 46.87, 27.11.

N-([1,1'- biphenyl ]-4- yl )-9,9- dimethyl -N-(4-(9-(4-(((4- vinylbenzyl ) oxy ) methyl ) phenyl ) -9H- carbazol -3- yl ) phenyl ) -9H- tertiary -2- amine synthesis : In a glove box filled with nitrogen, use (4-(3-(4- ([1,1'-biphenyl]-4-yl(9,9-dimethyl-9H-fluorene-2-yl)amino)phenyl)-9H-carbazol-9-yl)phenyl) A 100 mL round bottom flask was filled with methanol (4.40 g, 6.21 mmol, 1.00 equiv) and 35 mL of THF. Sodium hydride (0.224 g, 9.32 mmol, 1.50 equiv) was added portionwise, and the mixture was stirred for 30 minutes. A reflux condenser was attached, the unit was sealed and removed from the glove box. 4-Chloromethylvinylbenzene (1.05 mL, 7.45 mmol, 1.20 equiv) was injected, and the mixture was refluxed until the starting material was consumed. The reaction mixture was cooled (ice bath) and quenched cautiously with isopropanol. Sat. aq. _NH4Cl was added, and the product was extracted with ethyl acetate. The combined organic fractions were washed with brine, dried over _MgSO4 , filtered, concentrated, and purified by silica chromatography. The product has the following properties: ¹ H-NMR (400 MHz, CDCl ₃ ): δ 8.35 (s, 1 H), 8.18 (dt, J = 7.8, 1.0 Hz, 1 H), 7.74 to 7.47 (m, 14 H) , 7.47 to 7.35 (m, 11 H), 7.35 to 7.23 (m, 9 H), 7.14 (s, 1 H), 6.73 (dd, J = 17.6, 10.9 Hz, 1 H), 5.76 (dd, J = 17.6, 0.9 Hz, 1 H), 5.25 (dd, J = 10.9, 0.9 Hz, 1 H), 4.65 (s, 4 H), 1.45 (s, 6 H). ¹³ C-NMR (101 MHz, CDCl ₃ ): δ 155.13, 153.56, 147.25, 147.03, 146.43, 141.28, 140.61, 140.13, 138.94, 137.64, 137.63, 137.16, 137.00, 136.48, 136.37, 135.06, 134.35, 132.94, 129.21 , 128.73, 128.05, 127.96, 127.76, 126.96, 126.94, 126.79, 126.62, 126.48, 126.33, 126.09, 125.14, 124.54, 123.89, 123.54, 123.48, 122.46, 1 20.66, 120.34, 120.04, 119.44, 118.82, 118.31, 113.92, 110.01 , 109.90, 72.33, 71.61, 46.87, 27.11. Synthesis of HTL2 Monomer

4'-((9,9- Dimethyl -9H- fen - 2- yl )(4-(1- methyl -2- phenyl- 1H - indol -3- yl ) phenyl ) amino ) Synthesis of -[1,1'- biphenyl ]-4- formaldehyde : at 80°C, under a nitrogen atmosphere, N-(4-bromophenyl)-9,9-dimethyl-N-(4 -(1-methyl-2-phenyl-1H-indol-3-yl)phenyl)-9H-oxene-2-amine (1) (12.9 g, 20 mmol), (4-formylphenyl A mixture of boronic acid (1.07 g, 30 mmol), Pd(PPh ₃ ) ₄ (693 mg, 1155, 3%), 2M K ₂ CO ₃ (4.14 g, 30 mmol, 15 mL H2O) and 45 mL of THF was heated up to 12 h. After cooling to room temperature, the solvent was removed under vacuum and the residue was extracted with dichloromethane. After cooling to room temperature, the solvent was removed under vacuum and then water was added. _The mixture was extracted with _CH2Cl2 . The organic layer was collected and dried over anhydrous sodium sulfate. After filtration, the filtrate was evaporated to remove the solvent, and the residue was purified by silica gel column chromatography to obtain a pale yellow solid (yield: 75%). MS (ESI): 671.80 [M+H] ₊ . 1H-NMR (CDCl ₃ , 400 MHz, TMS, ppm): δ 10.03 (s, 1H), 7.94 (d, 2H), 7.75 (d, 2H), 7.64 (m, 2H), 7.55 (d, 2H) , 7.41 (m, 9H), 7.23 (m, 8H), 7.09 (m, 3H), 3.69 (s, 3H), 1.43 (s, 6H).

(4'-((9,9- Dimethyl -9H- fluorene -2- yl )(4-(1- methyl -2- phenyl- 1H - indol -3- yl ) phenyl ) amino )-[1,1'- biphenyl ]-4- yl ) methanol synthesis : under nitrogen atmosphere, to 4'-((9,9-dimethyl-9H-fluorene-2-yl )(4-(1-methyl-2-phenyl-1H-indol-3-yl)phenyl)amino)-[1,1'-biphenyl]-4-carbaldehyde (10 g, 15 mmol ) in 50 mL THF and 50 mL ethanol was added NaBH ₄ (2.26 g, 60 mmol). The solution was allowed to stir at room temperature for 2 h. Next, aqueous hydrochloric acid solution was added until the pH was 5, and the addition was maintained for another 30 min. The solvent was removed under vacuum and the residue was extracted with dichloromethane. The product was then obtained by removing the solvent and used in the next step without further purification (yield: 95%). MS (ESI): 673.31 [M+H] ⁺ .

9,9- Dimethyl -N-(4-(1- methyl -2- phenyl- 1H - indol -3- yl ) phenyl )-N-(4'-(((4- vinyl Synthesis of benzyl ) oxy ) methyl )-[1,1'- biphenyl ]-4- yl )-9H- oxene -2- amine : to (4'-((9,9-dimethyl -9H-Oxen-2-yl)(4-(1-methyl-2-phenyl-1H-indol-3-yl)phenyl)amino)-[1,1'-biphenyl]-4 -yl) Methanol (9.0 g, 13.4 mmol) in 50 mL of anhydrous DMF was added NaH (482 mg, 20.1 mmol), and the mixture was stirred at room temperature for 1 h. And 4-chloromethylvinylbenzene (3.05 g, 20.1 mmol) was added to the above solution via syringe. The mixture was heated to 50 °C within 24 h. After quenching with water, the mixture was poured into water to remove DMF. The residue was filtered, and the resulting solid was dissolved with dichloromethane, which was then washed with water. The solvent was removed under vacuum and the residue was extracted with dichloromethane. The product was then obtained by silica gel column chromatography (yield: 90%). MS (ESI): 789.38 [M+H] ⁺ . 1H-NMR (CDCl ₃ , 400 MHz, TMS, ppm): δ 7.59 (d, 4 H), 7.48 (m, 2 H), 7.40 (m, 18 H), 7.22 (m, 8 H), 6.71 ( dd, 1 H), 5.77 (d, 1 H), 5.25 (d, 1 H), 4.58 (s, 4 H), 3.67 (s, 3 H), 1.42 (s, 6 H). Synthesis of HTL3 Monomer

4'-([1,1'- biphenyl ]-4- yl (9,9- dimethyl -9H- fen -2- yl ) amino )-[1,1'- biphenyl ]-4- Synthesis of formaldehyde : using [1] (20 g, 38.7 mmol, 1 equivalent), 4-formylphenylboronic acid (6.42 g, 42.6 mmol, 1.1 equivalent), tetrahydrofuran (315 mL) and 2 M aqueous K ₂ CO ₃ (58 mL) filled a 1 L, 3-necked round bottom flask equipped with a thermocouple, condenser with N2 inlet, and a septum. The mixture was stirred and sparged with _N2 for 30 min. Pd(dppf) _Cl2 (0.55 g, 0.75 mmol, 0.02 equiv) was added and the reaction was heated to reflux over 21 h. Tetrahydrofuran was distilled off, and the reaction was diluted with water (300 mL), and extracted with dichloromethane (2 x 300 mL). The combined org. phases were dried over _MgSO4 , filtered and concentrated onto silica. Material was chromatographed using a gradient eluent (1 column volume hexane increasing to 1:1 hexane:dichloromethane over 8 column volumes, then maintaining a 1:1 ratio for 10 column volumes). The combined fractions were condensed to give a bright yellow solid (15.2 g, 72%, 99.5% pure).

¹ H NMR (400 MHz, C ₆ D6) δ 9.74 (s, 1 H), 7.61 (2 H, dd, J = 8 Hz, 2 Hz), 7.55 (2 H, dd, J = 20 Hz, 2.4 Hz ), 7.50 - 7.46 (5 H, multimodal), 7.37 - 7.11 (15 H, multimodal), 1.28 (s, 6 H).

¹³ C NMR (101 MHz, C ₆ D6) δ 190.64, 155.70, 153.83, 148.64, 147.24, 147.05, 146.04, 140.76, 139.10, 136.52, 135.61, 135.38, 133.68, 130.22, 129 .01, 128.43, 128.36, 127.39, 127.18, 127.12, 126.95, 126.94, 124.93, 124.44, 123.82, 122.74, 121.29, 119.88, 119.61, 46.95z, 26.93.

N-([1,1'- biphenyl ]-4- yl )-9,9- dimethyl -N-(4'- vinyl- [1,1'- biphenyl ]-4- yl )- Synthesis of 9H- tertilene -2- amine : Fill a 500 mL round-bottom flask with a 3-neck round-bottom flask with methyltriphenylphosphonium bromide (18.44 g, 51.6 mmol, 2 equivalents) and anhydrous tetrahydrofuran (148 mL), and the The flask was equipped with thermocouple, condenser with N2 inlet and separator. Potassium tert-butoxide (6.8 g, 60.6 mmol, 2.3 equiv) was added, and the mixture was stirred for 15 minutes. 4'-([1,1'-biphenyl]-4-yl(9,9-dimethyl-9H-fluorene-2-yl)amino)-[1,1'-biphenyl]-4 - Formaldehyde [9] (14.03 g, 25.9 mmol, 1 equiv) was dissolved in anhydrous tetrahydrofuran (74 mL) and added to the methyltriphenylphosphonium bromide solution. The reaction was stirred at room temperature for 16 h. Water (4 mL) was added, and the mixture was filtered through a plug of silica. The pad was flushed with dichloromethane (423 g), and the filtrate was adsorbed to silica and chromatographed using gradient eluents (1 column volume hexane increasing to 19 column volumes 80:20 hexane:2 Chloromethane, followed by an 80:20 ratio for 10 column volumes). The combined fractions were condensed to give a yellow oily solid which was triturated with methanol to give a white solid (10.57 g, 76%, 99.8% pure).

¹ H NMR (400 MHz, C ₆ D6 ) δ 7.55 - 7.43 (multiple peaks, 11 H), 7.33 - 7.10 (multiple peaks, 13 H), 6.63 (1 H, dd, J = 20 Hz, 12 Hz), 5.66 (1 H, dd, J = 20 Hz, 1.2 Hz), 5.11 (1 H, dd, J = 12 Hz, 1.2 Hz), 1.27 (s, 6 H).

¹³ C NMR (101 MHz, C ₆ D6) δ 155.61, 153.85, 147.66, 147.57, 147.39, 140.91, 140.28, 139.25, 136.82, 136.51, 136.04, 135.41, 135.19, 128.98, 128 .28, 128.02, 127.78, 127.34, 127.04, 127.02, 126.98, 126.94, 124.60, 124.52, 124.15, 122.71, 121.23, 119.81, 119.30, 113.42, 46.93, 26.94. Synthesis of HTL4 Monomer

4-(3,6- bis (4-([1,1'- biphenyl ]-4- yl (9,9- dimethyl -9H- fluorene - 2- yl ) amino ) phenyl )-9H Synthesis of -carbazol -9- yl ) benzaldehyde : Heating 4-(3,6-dibromo-9H-carbazol - 9-yl)benzaldehyde (6.00 g, 17.74 mmol) at 80°C overnight under nitrogen , N-([1,1'-biphenyl]-4-yl)-9,9-dimethyl-N-(4-(4,4,5,5-tetramethyl-1,3,2 -dioxaborolan-2-yl)phenyl)-9H-tertire-2-amine (15.70 g, 35.49 mmol), Pd(PPh ₃ ) ₃ (0.96 g), 7.72 g K ₂ CO ₃ , 100 mL A mixture of THF and 30 mL _H2O . After cooling to room temperature, the solvent was removed under vacuum and the residue was extracted with dichloromethane. The product was then obtained by silica gel column chromatography using petroleum ether and dichloromethane as eluents to afford the desired product (14.8 g, 92% yield). ¹ H NMR (CDCl ₃ , ppm): 10.14 (s, 1H), 8.41 (d, 2H), 8.18 (d, 2H), 7.86 (d, 2H), 7.71 (dd, 2H), 7.56-7.68 (m , 14H), 7.53 (m, 4H), 7.42 (m, 4H), 7.26-735 (m, 18H), 7.13-7.17 (d, 2H), 1.46 (s, 12H).

(4-(3,6- bis (4-([1,1'- biphenyl ]-4- yl (9,9- dimethyl -9H- fluorene - 2- yl ) amino ) phenyl )- Synthesis of 9H- carbazol -9- yl ) phenyl ) methanol : 4-(3,6-bis(4-([1,1'-biphenyl]-4-yl(9,9-dimethyl -9H-Oxen-2-yl)amino)phenyl)-9H-carbazol-9-yl)benzaldehyde (10.0 g, 8.75 mmol) was dissolved in 80 mL THF and 30 mL ethanol. _NaBH4 (1.32 g, 35.01 mmol) was added under nitrogen atmosphere over 2 hours. Then, aqueous hydrochloric acid was added until pH 5, and the mixture was kept stirring for 30 min. The solvent was removed under vacuum and the residue was extracted with dichloromethane. The product was then dried under vacuum and used in the next step without further purification.

N,N'-((9-(4-(((4- vinylbenzyl ) oxy )methyl ) phenyl ) -9H- carbazole -3,6- diyl ) bis (4,1 -Synthesis of -phenylene )) bis (N-([1,1'- biphenyl ]-4- yl )-9,9- dimethyl -9H- oxene -2- amine) : 0.45 g 60% NaH was added to (4-(3,6-bis(4-([1,1'-biphenyl]-4-yl(9,9-dimethyl-9H-fluorene-2-yl)amino)benzene 10.00 g, 100 mL of dry DMF solution of -9H-carbazol-9-yl)phenyl)methanol. After stirring at room temperature for 1 h, 2.00 g of 1-(chloromethyl)-4-vinylbenzene were added via syringe. The solution was stirred at 60 °C under _N2 and tracked by TLC. After consumption of starting material, the solution was allowed to cool and poured into ice water. After filtering and washing with water, ethanol and petroleum ether respectively, the crude product was obtained and dried overnight in a vacuum oven at 50°C, and then flash silica gel column chromatography with dichloromethane and The gradient evolution of petroleum ether eluent (1:3 to 1:1) was used for purification. The crude product was further purified by recrystallization from ethyl acetate and column chromatography, achieving a purity of 99.8%. ESI-MS (m/z, Ion): 1260.5811, (M+H) ⁺ . ¹ H NMR (CDCl ₃ , ppm): 8.41 (s, 2 H), 7.58-7.72 (m, 18 H), 7.53 (d, 4 H), 7.38-7.50 (m, 12 H), 7.25-7.35 ( m, 16 H), 7.14 (d, 2 H), 6.75 (q, 1 H), 5.78 (d, 1 H), 5.26 (d, 1 H), 4.68 (s, 4 H), 1.45 (s, 12H). For the preparation of HTL polymers:

In a glove box, dissolve the monomer (1.00 equiv) in anisole (electronic grade, 0.25 M). The mixture was heated to 70 °C, and AIBN solution (0.20 M in toluene, 5 mol%) was injected. The mixture was stirred until the monomer was completely consumed, at least 24 hours (a 2.5 mol% portion of the AIBN solution could be added to complete the conversion). The polymer was precipitated with methanol (10 x volume of anisole) and isolated by filtration. The filtered solid was rinsed with an additional portion of methanol. The filtered solid was redissolved in anisole and the precipitation/filtration procedure was repeated two more times. The isolated solid was placed in a vacuum oven overnight at 50 °C to remove solvent. HTL polymer structure and molecular weight ( MW )

M _n : average MW; M _w : average weight MW; M _z : average Z MW; M _z+1 : average Z+1 MW. PDI = M _w /M _n : polydispersity QLED device manufacturing

The QLED device was constructed as follows. A glass substrate (20 mm x 15 mm) with pixelated tin-doped indium oxide (ITO) electrodes (Ossila Inc.) was used. ITO was treated with oxygen plasma. The hole injection layer (HIL) was Plexcore™ OC RG-1200 (poly(thiophene-3-[2-(2-methoxyethoxy)ethoxy]-2,5-di base). The HIL solution was filtered with a 0.45 micron polyvinylidene fluoride (PVDF) syringe filter and deposited into the layer by dynamic spin coating, whereby 20 μL of the solution was dispensed onto the rotating substrate. The spin speed was approximately 2000 RPM To achieve a film thickness of approximately 40 nm. Using a foam swab, some portions of the deposited film covering the segment of the electrode were removed with toluene. The device was then annealed for 30 minutes at 150° C. on a hot plate in an inert atmosphere.

To form the hole transport layer (HTL), each HTL polymer was individually dissolved in electronic grade anisole (2% w/w) at elevated temperature (<100°C) to ensure complete dissolution and penetration. Pass through a 0.2 μm polytetrafluoroethylene (PTFE) filter. Materials were deposited into layers by dynamic spin coating, whereby 20 μL of the solution was dispensed onto the rotating substrate. The spin speed (approximately 2000 RPM) was adjusted for each material to achieve a film thickness of approximately 40 nm. Using a foam swab, some parts of the deposited film covering the section of the electrode were removed with toluene. The device was then annealed at 205° C. for 10 minutes on a hot plate in an inert atmosphere. Will be made of poly[(9,9-dioctyl fenyl-2,7-diyl)-co-(4,40-(N-(4-second butylphenyl))diphenylamine)] (TFB) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) The well-studied literature HTL for the composition of a 50:50 mixture is used as a reference.

The light emitting layer is selected from the list below. Each material was deposited into layers by dynamic spin coating, whereby 20 μL of the solution was dispensed onto the rotating substrate. The spin speed (approximately 2000 to 4000 RPM) was adjusted for each material to achieve a film thickness of approximately 5 nm to 15 nm. Using a foam swab, some parts of the deposited film covering the section of the electrode were removed with toluene. The device was then annealed at 180° C. for 10 minutes on a hot plate in an inert atmosphere.

Emissive layer materials were used as follows: 1) CdSe/ZnS (520 nm emission); 2) InP/ZnS (620 nm emission); and 3) CdS/CdSe/ZnSe DHNR (600 nm emission).

CdSe/ZnS and InP/ZnS were purchased from Aldrich as catalog numbers 748021 and 776777, respectively. Quantum dots were dispersed in toluene at a concentration of about 20 mg/ml and used as received.

Synthesized according to the following procedure DHNR .

Technical grade trioctylphosphine oxide (90%), technical grade trioctylphosphine (TOP) (90%), technical grade oleic acid (90%), technical grade octadecene (90%), CdO (99.5 %) , Zinc acetate (99.99%), S powder (99.998%) and Se powder (99.99%) were obtained from Sigma Aldrich. N-octadecylphosphonic acid (ODPA) was obtained from PCI Synthesis. ACS grade chloroform and methanol were obtained from Fischer Scientific. All chemicals were used as received.

Synthesis of CdS nanorods : CdS nanorods were prepared in a similar manner to the established method 14 . Reactions were carried out in a standard Schlenk line under N2 atmosphere. First, 2.0 g (5.2 mmol) trioctylphosphine oxide, 0.67 g (2.0 mmol) ODPA, and 0.13 g (2.0 mmol) CdO in a 50 ml three-necked round-bottom flask were degassed in vacuum at 150 °C for 30 min, And then heated to 350 °C with stirring. The brown solution in the flask usually became optically clear and colorless after 1 h as the Cd-ODPA complex formed at 350 °C. The solution was then cooled and degassed at 150 °C for 10 min to remove complex by-products including _O2 and _H2O . After degassing, the solution was reheated to 350 °C under _N2 atmosphere. The S precursor containing 16 mg (0.5 mmol) S dissolved in 1.5 ml TOP was quickly injected into the flask with a syringe. Therefore, the reaction mixture was quenched to 330°C at which CdS growth was performed. After 15 min, CdS nanorod growth was terminated by cooling to 250°C, at which point CdSe growth on Cds nanorods was performed. Aliquots of CdS nanorods were taken and cleaned by precipitation with methanol and butanol for characterization. The CdS/CdSe heterostructure was formed by slowly adding the Se precursor to the same reaction flask maintained under _N2 atmosphere as described below.

Synthesis of CdS/CdSe nanorod heterostructures : One-pot synthesis of rod-rod-rod-shaped nanorod heterostructures was performed in a similar manner to established methods. After the formation of CdS nanorods, the Se precursor containing 20 mg (0.25 mmol) Se dissolved in 1.0 ml TOP was slowly injected at a rate of 4 ml ^h at 250 °C via a syringe pump (total injection time about 15 min). The reaction mixture was then allowed to stir for a further 5 min at 250° C., followed by rapid cooling by gas sparging. Aliquots of the CdS/CdSe nanorod heterostructures were taken and cleaned for analysis by precipitation with methanol and butanol. The final reaction mixture was dissolved in chloroform and centrifuged at 2,000 RPM. The precipitate was redissolved in chloroform for use in the next step. When diluted by a factor of 10, this solution of CdS/CdSe nanorod heterostructures has an optical density of 0.75 (in a cuvette with an optical path length of 1 cm) at the CdS band-edge absorption peak.

Synthesis of CdS/CdSe/ZnSe DHNR : CdS/CdSe/ZnSe DHNR was synthesized by growing ZnSe onto CdS/CdSe nanorod heterostructure. For the Zn precursor, 6 ml of octadecene, 2 ml of oleic acid, and 0.18 g (1.0 mmol) of zinc acetate were degassed at 150 °C for 30 min. The zinc mixture was heated to 250 °C under _N2 atmosphere, and thus zinc oleate was formed after 1 h. 2 ml of the previously prepared CdS/CdSe stock solution was injected into the zinc oleate solution after cooling to 50 °C. Chloroform was evaporated in vacuo at 70 °C for 30 min. ZnSe growth was initiated by slowly injecting a Se precursor containing 39 mg (0.50 mmol) Se dissolved in 2.0 ml TOP into the reaction mixture at 250 °C. The thickness of ZnSe on the CdS/CdSe nanorod heterostructure is controlled by the amount of Se implanted. ZnSe growth was terminated by removing the heating mantle after injecting the desired amount of Se precursor. After washing twice with a mixture of chloroform and methanol (1:1 volume ratio), CdS/CdSe/ZnSe DHNR was finally dispersed in toluene (about 30 mg ml ⁻¹ ).

ZnO synthesis : ZnO was used as the electron transport layer (ETL). ZnO was synthesized according to published literature procedures. Briefly, a solution of potassium hydroxide (1.48 g) in methanol (65 ml) was added to a solution of zinc acetate dihydrate (2.95 g) in methanol (125 ml), and the reaction mixture was stirred at 60°C for 2 Hour. The mixture was then cooled to room temperature and the precipitate was washed twice with methanol. The precipitate was suspended in 1-butanol to form the final ZnO solution. ZnO was deposited into the layer by dynamic spin coating, whereby 20 μL of the solution was dispensed onto the rotating substrate. Adjust the spin speed (approximately 2000 RPM) to achieve a film thickness of approximately 30 nm. Using a foam swab, some portions of the deposited film covering the section of the electrode were removed with butanol. The device was then annealed at 120° C. for 10 minutes on a hot plate in an inert atmosphere.

A 100 nm layer of aluminum was deposited by thermal evaporation from a graphite crucible under high vacuum through a cathode shadow mask.

The QLED devices were tested as follows. Current-voltage-illumination light (JVL) data was collected on unencapsulated devices inside a _N2 glove box using custom test panels from Ossila Inc. The board consists of two components in combination: 1) the X100 Xtralien™ precision test source, and 2) the smart PV and OLED board; these components are used to measure current and light output in 0.1 V increments QLED devices were tested over a voltage range of −2 V to 7 V. Light output was measured using a gaze-responsive photodiode including a filter that mimics the sensitivity of a photopic eye (Centronic E series). The device was placed inside the test chamber on the board and covered with the photodiode assembly. Electrical contact to the ITO electrodes is made by a series of spring-actuated gold probes inside the smart board assembly. The photodiode is located at a distance of 3 mm above the ITO substrate. Determining important device parameters from JVL data, including voltage required to achieve luminance of 1000 cd/m ² , current efficiency (in cd/A) of QLEDs at 1000 cd/m ² , and 10 mA/cm ² in QLEDs The driving voltage required for the current. Geometry factors are applied to the measured photodiode current to take into account the distance between the photodiode and the substrate (3 mm) and the relative positioning of each pixel on the substrate. Results and Analysis

The HTL polymers listed below were fabricated as example quantum dot light emitting diodes. The example diodes performed acceptable in all tests involving quantum dots composed of CdSe/ZnS, InP/ZnS, and DHNR. The example devices were shown to perform acceptable with quantum dot emission ranging from 520 nm to 600 nm and to 620 nm, as listed in the table below. The example devices are shown to perform acceptable with spherical and rod-shaped quantum dots. The HTL compounds lead to improved QLED device efficiency and driving voltage as compared to the reference example. QLED device performance with spherical CdSe/ZnS quantum dots emitting at 520 nm QLED device performance with spherical InP/ZnS quantum dots emitting at 620 nm QLED device performance with DHNR emitting at 600 nm

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Claims (11)

A quantum dot light-emitting device, which includes: i) a compound selected from group II-VI compounds, group II-V compounds, group III-VI compounds, group III-V compounds, group IV-VI compounds, A light-emitting layer of at least one semiconductor nanoparticle made of a group of semiconductor materials consisting of group I-III-VI compounds, group II-IV-VI compounds, group II-IV-V compounds, or any combination thereof; and ii) a polymer for a hole injection or hole transport layer, wherein said polymer comprises as polymerized units at least one or more monomers having a first monomer structure comprising: a ) a polymerizable group, b) an electroactive group having the formula NAr ¹ Ar ² Ar ³ , wherein Ar ¹ , Ar ² and Ar ³ are independently C ₆ to C ₅₀ aromatic substituents, and (c) A linker group, which connects the polymerizable group and the electroactive group, wherein the polymerizable group is selected from a vinyl group, benzocyclobutene, acrylate or methacrylate group, trifluoroethylene ether, cinnamate or chalcone, diene, ethoxyacetylene and 3-ethoxy-4-methylcyclobut-2-enone. The quantum dot light-emitting device as described in claim 1, wherein the polymer has a molecular weight of at least 5,000 and not greater than 10,000,000. The quantum dot light-emitting device as described in claim 1 of the patent application, wherein the polymerizable group is a vinyl group. The quantum dot light-emitting device as described in item 1 of the scope of the patent application, wherein the electroactive group having the formula NAr ¹ Ar ² Ar ³ contains the following:

The quantum dot light-emitting device as described in claim 1 of the patent application, wherein the polymer further includes a second monomer selected from the following:

The quantum dot light-emitting device as described in item 1 of the scope of the patent application, wherein the linker group is selected from the group consisting of: a covalent bond; -O-; -alkylene-; -extension Base-;-Alkylene-arylylene-;-Arylylene-Alkylene-; ;-O-Alkylene-O-;-O-Alkylene-O-Alkylene-O-; ; -O-(CH ₂ CH ₂ -O) _n -, wherein n is an integer from 2 to 20; -O-alkylene-O-alkylene-; -O-alkylene-O-alkylene Aryl-; -O-arylylene-O-; -O-arylylene-O-alkylene-; and -O-arylylene-O-arylylene. The quantum dot light-emitting device as described in claim 1, wherein the polymer further includes a p-type dopant. The quantum dot light-emitting device as described in item 1 of the scope of the patent application, wherein the semiconductor nanoparticles are doped with rare earth elements, transition metal elements or any combination thereof. The quantum dot light-emitting device as described in claim 1, wherein the semiconductor nanoparticles have a core-shell structure, so that an additional material is coated on the outside of an inner part of the semiconductor nanoparticles, And the additional material is selected from the group consisting of Group IV compounds, Group II-VI compounds, Group II-V compounds, Group III-VI compounds, Group III-V compounds, Group Group IV-VI compounds, Group I-III-VI compounds, Group II-IV-VI compounds, Group II-IV-V compounds, or any combination thereof. The quantum dot light-emitting device as described in item 1 of the patent claims, wherein the semiconductor nanoparticles have at least one dimension—100 nanometers or less in length. The quantum dot light-emitting device as described in item 1 of the scope of patent application, wherein the semiconductor nanoparticles include a one-dimensional nanoparticle, and the one-dimensional nanoparticle has been placed in contact with one of the one-dimensional nanoparticle At either or each end of a single end cap or a plurality of end caps.