WO2013096918A1

WO2013096918A1 - Crosslinking triscarbazole hole transport polymers

Info

Publication number: WO2013096918A1
Application number: PCT/US2012/071506
Authority: WO
Inventors: Carlos Zuniga; Seth Marder; Wojciech HASKE; Bernard Kippelen; Roland Martin; Jessem ABDALLAH
Original assignee: Georgia Tech Research Corporation; Solvay Sa
Priority date: 2011-12-22
Filing date: 2012-12-21
Publication date: 2013-06-27

Abstract

Provided herein are triscarbazole hole transport polymers that are highly processable in solution and capable of crosslinking by the application of heat and/or light. These polymers allow for solvent resistant and allow solution processing of subsequent layers while maintaining good hole transport abilities and device efficiencies.

Description

CROSSLINKING TRISCARBAZOLE HOLE TRANSPORT POLYMERS

BACKGROUND

The study of materials, processing, and organic light-emitting diodes (OLED) devices is a rapidly developing field. OLED devices are of interest partly because of their ability to be processed onto a variety of substrates, their potential for low cost fabrication, and the possibility for fabricating energy-efficient displays and/or solid-state lighting sources. Early OLED devices were based on fluorescent organic materials in which emission is only obtained from hole-electron recombination events that result in the formation of singlet excited states, placing limitations on the maximum efficiency of devices. Use of

phosphorescent transition-metal-based emitters, enabling emission from both singlet and triplet excited states, was first reported in 1995 and has since become common. Continuing progress in increasing the performance and development of OLED devices has commonly been the result of new material and new complex architectures employing a variety of multilayers with different functions including: hole and electron injection and transport; hole, electron, and exciton blocking; and acting as a host for phosphorescent emitters.

The highest efficiency devices in the prior art are generally those fabricated using high-vacuum vapor deposition. This approach permits the fabrication of well-defined multilayers with relative ease. However, vacuum-processing is time-consuming and expensive, while fabrication on large-area substrates can also be problematic. In contrast, solution-based approaches have the potential to facilitate rapid and low-cost processing and can be extended to large area substrates, and to high-throughput reel-to-reel processing. At the same time, higher molecular- weight materials that are difficult to be vapor-deposited, such as polymers or oligomers, can show good morphological stability.

One challenge of creating multilayer architectures using solution-processing is that the deposition of a second layer from solution sometimes causes a partial dissolution of the preceding layer if the solvent required for the second material also dissolves the first. The

"orthogonal solvent" approach for addressing this problem (i.e. careful selection of solvents so that the solvent for the second layer does not dissolve the first layer) is often not practical to implement. An alternative approach is to insolubilize by crosslinking the organic material in the first layer following solution-processing and before depositing the second layer. Therefore, a need exists for solution-processable and crosslinking materials (e.g., polymers and small molecules) suitable for the hole-transport layer of OLED devices that are capable of achieving high external quantum efficiency.

SUMMARY

Provided herein are polymers that are highly processable in solution and capable of crosslinking by the application of heat and/or light. These polymers allow for solvent resistant and allow solution processing of subsequent layers while maintaining good hole transport abilities and device efficiencies.

Embodiments described herein include, for example, compositions, articles, devices, and methods for making.

For example, provided is a composition comprising at least one polymer with crosslinking groups, said polymer comprising one or more type (I) subunits represented by formula (I) and optionally one or more type (II) subunits represented by formula (II):

wherein: X, Y, and Z are each independently H, alkyl, F or fluoroalkyl; XL is a crosslinking group; and TCz is an organic group comprising at least one optionally substituted triscarbazole group linked to a linker group, said triscarbazole group optionally comprises one or more crosslinking groups.

In one embodiment, the TCz group is represented by formula (III) or formula (IV):

(III) (IV)

wherein: L is an linker group; Rl, R2, R3, and R4 are each independently a hydrogen, a halogen, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted heteroalkyl group, or an optionally substituted heteroaryl group; XL, XLl, XL2, XL3, and XL4 are each independently a crosslinking group; and kl, k2, k3, and k4 are each 0, 1 or 2.

Also provided is a composition comprising at least one polymer with crosslinking groups, said polymer comprising at least one type (I) subunit represented by formula (XII) or formula (XIII) and optionally at least one type (II) subunit represented by formula (XIV):

<^XIV> ; wherein Rl, R2, R3, R4, R5, R6, R7, R8, R9, RIO, Rl l, R12, R13, R14, R15,

R16, R17, and R18 are each independently selected from the group consisting of hydrogen, halogen, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroalkyl, optionally substituted heteroaryl, and crosslinking group; wherein XL is a crosslinking group; and wherein said crosslinking group comprises a reactive group optionally linked to a linker group selected from the group consisting of optionally substituted alkylene, optionally substituted arylene, optionally substituted heteroalkylene, and optionally substituted heteroarylene.

Moreover, also provided is a hole transport layer comprising the composition discussed above, as well as an electroluminescence device comprising the hole transport layer. The electroluminescence device can additionally comprise an anode, a hole injection layer, an emissive layer and a cathode. In one embodiment, the hole transport layer is solution deposited on the anode. In another embodiment, the polymer in the hole transport layer is thermally and/or photochemically crosslinked. Still in another embodiment, a hole injection layer is obtained by p-doping the crosslinked hole transport layer. In a further embodiment, the emissive layer of the electroluminescence device comprises phosphorescent emitters, and the external quantum efficiency of the electroluminescence device at 1,000 cd/m is at least 5% or least 10%.

Furthermore, also provided is a method for making en electroluminescence device, comprising: providing an anode layer; depositing the hole transport layer discussed above from solution onto the anode layer; and crosslinking the polymer to produce a crosslinked hole transport layer, wherein the crosslinked hole transport layer is substantially

insolubilized. In one embodiment, the method further comprises depositing an emissive layer from solution onto the crosslinked hole transporting layer.

Still further, also provided is a method for making an electroluminescence device, comprising: (i)providing a substrate; (ii) depositing the composition discussed above onto the substrate to form a layer; and (iii) rapidly heating said layer at a temperature of 150 °C or more for 60 minutes or less, wherein the polymer is crosslinked after said heating step. In one embodiment, the deposited layer is heated at a temperature of 200 °C or more. In another embodiment, the deposited layer is heated at a rate of 100 °C/minute or more. In a further embodiment, the deposited layer is heated at a temperature of 150 °C or more for 40 minutes or less. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows schematically how crosslinking permits solution processing of multiplayer OLED devices. The process can be used to fabricate either devices in which the active layers are entirely processed from solution, or hybrid devices containing both solution and vacuum-deposited layers. Crosslinking can also improve morphological stability of OLED active layers, for example, by suppressing phase segregation or crystallization.

FIG. 2 shows three exemplary embodiments of the crosslinking triscarbazole hole transport polymer described herein.

FIG. 3 shows performance of OLED devices with spin-coated Polymer 5.38 hole transport layer and evaporation-deposited CBP:Ir(ppy)3 emitting layer.

FIG. 4 shows performance of an exemplary OLED device with spin-coated Polymer 5.38 hole transport layer and spin-coated PolymerA:PolymerB:Ir(pppy)3 emitting layer.

FIG. 5 shows temperature profile and performance of an exemplary OLED device with spin-coated Polymer 5.38 hole transport layer cured by rapid thermal processing and evaporation-deposited CBP:Ir(ppy)3 emitting layer.

FIG. 6 shows temperature profile and performance of an exemplary OLED device with spin-coated Polymer 5.38 hole transport layer cured by rapid thermal processing and spin-coated PolymerA:PolymerB:Ir(pppy)3 emitting layer.

FIG. 7 shows performance of an exemplary OLED device with spin-coated Polymer 5.40 hole transport layer and evaporation-deposited CBP:Ir(ppy)3 emitting layer.

FIG. 8 shows performance of an exemplary OLED device with spin-coated Polymer 5.40 hole transport layer and spin-coated PolymerA:PolymerB:Ir(pppy)3 emitting layer.

FIG. 9 shows temperature profile and performance of an exemplary OLED device with spin-coated Polymer 5.40 hole transport layer cured by rapid thermal processing and evaporation-deposited CBP:Ir(ppy)3 emitting layer.

FIG. 10 shows temperature profile and performance of an exemplary OLED device with spin-coated Polymer 5.40 hole transport layer cured by rapid thermal processing and PolymerA:PolymerB:Ir(pppy)3 spin-coated emitting layer.

FIG. 11 shows performance of an exemplary OLED device with spin-coated Polymer 5.40 hole transport layer and spin-coated Compound XI :Ir(pppy)3 emitting layer. FIG. 12 shows performance of an exemplary OLED device with spin-coated

PEDOT:PSS hole injection layer, spin-coated Polymer 5.40 hole transport layer and spin- coated Compound Xl :Ir(pppy)3 emitting layer.

FIG. 13 shows performance of an exemplary OLED device with spin-coated

PEDOT:PSS hole injection layer, spin-coated Polymer 5.40 hole transport layer and spin- coated Compound X2:Ir(pppy)3 emitting layer.

FIG. 14 shows performance of an exemplary OLED device with spin-coated Polymer 5.40 hole transport layer and spin-coated Compound X2:Ir(pppy)3 emitting layer.

FIG. 15 shows performance of an exemplary OLED device with spin-coated Polymer 5.40 hole transport layer and spin-coated Compound X3:Ir(pppy)3 emitting layer.

FIG. 16 shows performance of an exemplary OLED device with spin-coated

PEDOT:PSS hole injection layer, spin-coated Polymer 5.40 hole transport layer and spin- coated Compound X3:Ir(pppy)3 emitting layer.

FIG. 17 shows performance of an exemplary OLED device with spin-coated

PEDOT:PSS hole injection layer, spin-coated Polymer 5.40 hole transport layer and spin- coated Compound Yl :Ir(pppy)3 emitting layer.

FIG. 18 shows performance of an exemplary OLED device with spin-coated

PEDOT:PSS hole injection layer, spin-coated Polymer 5.40 hole transport layer and spin- coated Compound Y2:Ir(pppy)3 emitting layer.

FIG. 19 shows performance of an exemplary OLED device with spin-coated

PEDOT:PSS hole injection layer, spin-coated Polymer 5.40 hole transport layer and spin- coated Compound Y3:Ir(pppy)3 emitting layer.

FIG. 20 shows performance of an exemplary OLED device with spin-coated

PEDOT:PSS hole injection layer, spin-coated Polymer 5.40 hole transport layer and spin- coated Compound Y4:Ir(pppy)3 emitting layer.

FIG. 21 shows performance of an exemplary OLED device with evaporation- deposited M0O₃ hole injection layer, spin-coated Polymer 5.40 hole transport layer and spin- coated Compound Y4:Ir(pppy)3 emitting layer.

FIG. 22 shows performance of an exemplary OLED device with spin-coated

PEDOT:PSS hole injection layer, spin-coated Polymer 5.40 hole transport layer and spin- coated Compound Y5:Ir(pppy)3 emitting layer. FIG. 23 shows performance of an exemplary OLED device with evaporation- deposited M0O₃ hole injection layer, spin-coated Polymer 5.40 hole transport layer and spin- coated Compound Y5:Ir(pppy)3 emitting layer.

DETAILED DESCRIPTION

INTRODUCTION

All references described herein are hereby incorporated by reference in their entirety. US Provisional applications 61/579,394 and 61/579,418 filed December 22, 2011 are hereby incorporated by reference.

Various terms are further described herein below:

"A", "an", and "the" refers to "at least one" or "one or more" unless specified otherwise.

"Optionally substituted" groups refers to, for example, functional groups that may be substituted or unsubstituted by additional functional groups. For example, when a group is unsubstituted by an additional group it can be referred to as the group name, for example alkyl or aryl. When a group is substituted with additional functional groups it may more generically be referred to as substituted alkyl or substituted aryl.

"Alkyl" refers to, for example, straight chain and branched alkyl groups having from 1 to 20 carbon atoms, or from 1 to 15 carbon atoms, or from 1 to 10, or from 1 to 5, or from 1 to 3 carbon atoms. This term is exemplified by groups such as for example methyl, ethyl, n- propyl, iso-propyl, n-butyl, t-butyl, n-pentyl, ethylhexyl, dodecyl, isopentyl, and the like.

"Aryl" refers to, for example, an aromatic carbocyclic group of from 6 to 14 carbon atoms having a single ring (e.g., phenyl) or multiple condensed rings (e.g., naphthyl or anthryl) which condensed rings may or may not be aromatic provided that the point of attachment is at an aromatic carbon atom. Preferred aryls include phenyl, naphthyl, and the like.

"Heteroalkyl" refers to, for example, an alkyl group wherein one or more carbon atom is substituted with a heteroatom. The heteroatom can be, for example, O, S, N, P, etc. "Heteroaryl" refers to, for example, an aryl group wherein one or more carbon atom is substituted with a heteroatom. The heteroatom can be, for example, O, S, N, P, etc. One example of heteroaryl is carbazole.

"Alkoxy" refers to, for example, the group "alkyl-O-" which includes, by way of example, methoxy, ethoxy, n-propyloxy, iso-propyloxy, n-butyloxy, t-butyloxy, n-pentyloxy, 1-ethylhex-l-yloxy, dodecyloxy, isopentyloxy, and the like.

"Aryloxy" can refer, for example, to the group "aryl-O-" which includes, by way of example, phenoxy, naphthoxy, and the like.

"Alkylene" refers to, for example, straight chain and branched alkylene groups having from 1 to 20 carbon atoms, or from 1 to 15 carbon atoms, or from 1 to 10, or from 1 to 5, or from 1 to 3 carbon atoms. This term is exemplified by groups such as methylene, ethylene, n-propylene, z^'so-propylene, n-butylene, t-butylene, n-pentylene, ethylhexylene, dodecylene, isopentylene, and the like.

"Arylene" refers to, for example, an aromatic carbocyclic group of from 6 to 14 carbon atoms having a single ring (e.g., phenylene) or multiple condensed rings (e.g., naphthylene or anthrylene) which condensed rings may or may not be aromatic provided that the point of attachment is at an aromatic carbon atom. Preferred arylenes include phenylene, naphthylene, and the like.

"Heteroalkylene" refers to, for example, an alkylene group wherein one or more carbon atom is substituted with a heteroatom. The heteroatom can be, for example, O, S, N, P, etc.

"Heteroarylene" refers to, for example, an arylene group wherein one or more carbon atom is substituted with a heteroatom. The heteroatom can be, for example, O, S, N, P, etc.

"Oxyalkylene" refers to, for example, the group "-alkylene-O-".

"Oxyarylene" refers to, for example, the group "-arylene-O-".

"Carbonyl alkylene" refers to, for example, the group "-alkylene-C(O)-".

"Carbonyl arylene" refers to, for example, the group "-arylene-C(O)-".

"Carboxyl alkylene" refers to, for example, the group "-alkylene-C(0)-0-".

"Carboxyl arylene" refers to, for example, the group "-arylene-C(0)-0-".

"Ether" refers to, for example, the group -alkylene-O-alkylene-, -arylene-O-alkylene-, -arylene-O-arylene-, wherein the alkylene and arylene can be optionally substituted. "Ester" refers to, for example, the group -alkylene-C(0)-0-alkylene-, -arylene-C(O)- O-alkylene-, -arylene-C(0)-0-arylene-, wherein the alkylene and arylene can be optionally substituted.

"Ketone" refers to, for example, the group -alkylene-C(0)-alkylene-, -arylene-C(O)- alkylene-, -arylene-C(0)-arylene-, wherein the alkylene and arylene can be optionally substituted.

"Triscarbazole" refers to, for example, three or more carbazole groups connected to each other through aryl carbon-nitrogen bond and/or aryl carbon-carbon bond.

TYPE (I) SUBUNIT AND TYPE (II) SUBUNIT

Many embodiments described herein relate to a polymer comprising one or more type (I) subunits represented by formula (I) and optionally one or more type (II) subunits represented by formula (II):

⁽ and ⁽»⁾

wherein X, Y, and Z are each independently H, alkyl, F or fluoroalkyl; XL is a crosslinking group; TCz is an organic group comprising at least one optionally substituted triscarbazole group and an optional linker group; and wherein said triscarbazole group of the type (I) subunit optionally comprises one or more crosslinking groups.

Other embodiments of the type (I) subunits include, for example, formula (XII) or formula (XIII):

wherein Rl, R2, R3, R4, R5, R6, R7, R8, R9, RIO, Rl l, R12, R13, R14, R15, R16, R17, and R18 are each independently selected from the group consisting of hydrogen, halogen, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroalkyl, optionally substituted heteroaryl, and crosslinking group;

wherein XL is a crosslinking group;

wherein said crosslinking group comprises a reactive group optionally linked to a linker group selected from the group consisting of optionally substituted alkylene, optionally substituted arylene, optionally substituted heteroalkylene, and optionally substituted heteroarylene.

ther embodiments of the type (II) subunits include, for example, formula (XI):

(XI)

In some embodiments, the type (I) subunits are selected from one or several groups of

and the type (II) subunit are selected from one or several groups of

substituted alkyl group, an optionally substituted aryl group, an optionally substituted heteroalkyl group, or an optionally substituted heteroaryl group.

Optionally, the type (I) subunits may comprise one or more moieties from electron transporter, solubilizing groups, and compatibilizing groups. Optionally, the type (II) subunits may comprise one or more moieties from electron transporter, solubilizing groups, and compatibilizing groups.

In one embodiment, the type (I) subunits do not comprise any 2-phenyl-5-phenyl- 1,3,4-oxadiazole moeity. In another embodiment, the type (I) subunits comprise no oxadiazole moeity.

TCz AND TRISCARBAZOLE GROUP

Polymers comprising carbazole groups are known in the art and described in, for example, Lee et al., Polymer, 50:410-417 (2009), Wang et al., Journal of Polymer Science Part A: Polymer Chemistry, 46(16):5452-5460 (2008), US 2010/0084967, US

2010/0141126, EP 0850960, and WO 2010068205, all of which are incorporated herein by reference in their entireties.

The TZ group described herein comprises at least one optionally substituted triscarbazole group. In some embodiments, the TCz group can be represented by, for example, formula (III) or formula (IV):

(III) (IV)

The synthesis of the optionally substituted triscarbazole group in formula (III) is described in Jiang et al, J. Mater. Chem. 27:4918-26 (2011), while the synthesis of the optionally substituted triscarbazole group in formula (IV) is described in Brunner et al, J. Am. Chem. Soc. 726:6035-6042 (2004). Both references are incorporated herein by reference in their entireties.

In other embodiments, the TCz group can be represented by, for example, formula (V), formula (VI), formula (VII), or formula (VIII):

In some embodiments, the TCz group does not comprise any crosslinking group, i.e., kl, k2, k3, and k4 are each 0. In other embodiments, the TCz group comprises at least one crosslinking group, i.e., at least one of kl, k2, k3, and k4 is not 0.

In some embodiments, Rl, R2, R3, and R4 are each a hydrogen. In other embodiments, at least one of Rl, R2, R3, and R4 comprises an optionally substituted carbazole group. In further embodiments, Rl, R2, R3, and R4 each comprises an optionally substituted carbazole group.

When Rl, R2, R3, and R4 are each a hydrogen, the type (I) subunits can be represented by, for example, formula (IX):

(IX) When Rl, R2, R3, and R4 are each a carbazole group, the type (I) subunits represented by, for example, formula (X):

CROSSLINKING GROUP

Crosslinking groups are known in the art and described in, for example, Zunga et ah, Chem. Mater., 23:658-681 (2011), which is incorporated herein by reference in its entirety.

The crosslinking group can be, for example, a reactive group optionally linked to a linker group. Reactive groups are known in the art. Any reactive groups that are crosslinking by heat, light, chemical treatment or a combination thereof are within the scope of this application. The reactive group can be, for example, styrenic, acrylate, oxetane, cinnamate, chalcone, trifluorovinylether (TFVE), benzocyclobutane, silane, etc.

Examples of the reactive group include the following:

wherein R' can be, for example, a hydrogen, a halogen, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted heteroalkyl group, or an optionally substituted heteroaryl group, and wherein R" is a hydrogen, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted heteroalkyl group, or an optionally substituted heteroaryl group.

LINKER GROUP

Linker groups are known in the art and described in, for example, WO 2010149618, WO 2010149620, and WO 2010149622, all of which are incorporated herein by reference in their entireties.

The linker group can be, for example, an optionally substituted alkylene group, an optionally substituted arylene group, an optionally substituted heteroalkylene group, or an optionally substituted heteroaryl ene group.

More specifically, the linker group can be, for example, an alkylene group, an oxyalkylene group, an oligo-alkylene group, an oxyarylene group, a carbonyl alkylene group, a carbonyl arylene group, a carboxyl alkylene group, a carboxyl arylene group, an ether group, an ester group, or a ketone group.

In one embodiment, the linker group is resistant to oxidative, reductive, or thermal destruction under normal operating conditions of OLED devices.

In some embodiments, the linker group does not comprise any 2-phenyl-5-phenyl- 1,3,4-oxadiazole group. In other embodiments, the linker group comprise no oxadiazole group.

POLYMER

Polymers described herein are solution-processable and capable of crosslinking, and possess good hole transport ability.

The weight average molecular weight (Mw) of the polymer can be, for example, 5,000 Da or more, 10,000 Da or more, 15,000 Da or more, or 20,000 Da or more.

The polymer can comprise, for example, 3 or more crosslinking groups per macromolecule, or 5 or more crosslinking groups per macromolecule, or 10 or more crosslinking groups per macromolecule.

The polymer can be a homopolymer. In such homopolymer, the type (II) subunits are absent, and the type (I) subunits each comprises at least one crosslinking group. The polymer can be a copolymer of the type (I) subunits and the type (II) subunits. The copolymer can be, for example, a block copolymer, an alternating copolymer, or a random copolymer. In the copolymer, the type (I) subunits may or may not comprise a crosslinking group. In some embodiments of the copolymer, the molar fraction of the type (I) subunits can be, for example, between about 0.5 to about 0.99. In other embodiments of the copolymer, the molar fraction of the type (I) subunits can be, for example, between about 0.7 to about 0.9. The molar fraction of the type (I) subunits and the type (II) subunits can be varied to modify polymer properties such as conductivity, mechanical strength, solvent resistance, etc.

The polymer can also be a copolymer that further comprises one or more type (III) subunits. In such copolymer, the type (II) subunits may or may not be present. If the type (II) subunits are absent, then the type (I) subunits must comprise at least one crosslinking group.

In some embodiments, the type (III) subunits can comprise one or more moieties selected from the group consisting of electron transporters, solubilizing groups,

compatibilizing groups, and crosslinking groups. In particular, the type (III) subunits can comprise at least one crosslinking group comprising at least one reactive group having similar reactivity to the reactive groups of the type (II) subunits.

In some embodiments, the polymer does not comprise any 2-phenyl-5 -phenyl- 1,3,4- oxadiazole group. In other embodiments, the polymer comprises no oxadiazole group.

Examples of the polymer include the following:

In some embodiments, the type (I) subunits do not comprise any crosslinking groups, and the type (I) subunits and the type (II) subunits are arranged as a block copolymer. This architecture enables separated phases, including a non-crosslinked (continuous) phase concentrating the triscarbazole groups (optimizing hole transport) chemically connected to a (dispersed) phase which concentrates the crosslinking groups, with possible tuning to allow for high mobility (low Tg) of the reacting groups. Methods for producing styrenic block copolymers are known in the art.

Polymers described herein can be unexpectedly effective as hole transport material, and can be used to make highly efficient and stable OLED devices. Moreover, polymers described herein can have unexpectedly superior physical properties, such as high solubility and processability, and/or high resistance to crystallization and/or thermal degradation during OLED operation.

Further, polymers described herein can be readily soluble in common organic solvents. These polymers can be readily processed to form compositions useful in organic electronic devices, especially in the hole transport layer of OLED devices.

HOLE-TRANSPORT LAYER

Many embodiments described herein also relate to a hole transport layer. The hole transport layer can comprise, for example, the solution-processable crosslinking polymer described herein. The hole transport layer can further comprise, for example, a different crosslinking material.

The hole transport layer can be fabricated from a solution comprising the solution- processable crosslinking polymer described herein. The solution can further comprise, for example, an organic solvent such as chlorobenzene, a photoacid generator such as PAG: 4- ((2-Hydroxytetradecyl)oxy)-phenyl)phenyliodonium hexafluoroantimonate, and/or a thermoacid generator such as TAG: 4-isopropyl-4'-methyldiphenyl iodonium

tetrakis(pentafluorophenyl)borate.

The solution can comprise, for example, between 0.1-50 wt.% of the polymer, or between 0.2-25 wt.% of the polymer, or between 0.5-10 wt.% of the polymer, or between 1-5 wt.% of the polymer.

The hole transport layer can be fabricated by methods known in the art, such as spin coating from solution. If the hole transport layer is a film deposited from a solution, following solution processing, the film can be dried on a hotplate and subjected to crosslinking. The film can be crosslinked by heating at a temperature of, for example, 100- 200 °C, or 150-250 °C, or 200-300 °C, or 250-350 °C, or 300-400 °C. The film can also be crosslinked photochemically by, for example, UV.

HOLE-INJECTION LAYER

A hole injection layer can be formed from the solution-processable crosslinking polymer described herein modified by soluble molecular p-dopants known in the prior art. Examples of useful dopants are dithiol complexes of Cr(VI) and Mo(VI) described in Qi et al, J. Am. Chem. Soc. 131 : 12530-12531 (2009), incorporated herein by reference in its entirely. Other examples are described in WO 2008/061517, incorporated herein by reference in its entirety. Particularly useful a "Mo(tfd)3" and "Cr(tfd)3" as dopants:

ELECTROLUMINESCENCE DEVICE

Electroluminescence devices such as OLED are well known in the art. For example, the electroluminescence device can comprise at least an anode, a cathode, an emissive layer, and a hole transport layer comprising the solution-processable crosslinking polymer described herein. The electroluminescence device may also comprise en electron transport layer.

Many suitable materials for anode in electroluminescence devices are known in the art and include, for example, ITO, which can be applied by sputtering in a layer over an inert and transparent substrate such as glass.

Many suitable materials for cathode in electroluminescence devices are known in the art and include, for example, a combination of LiF as electron injecting material coated with a vacuum deposited layer of Al.

Many suitable materials for electron transport layer in electroluminescence devices are known in the art and include, for example, 2,9-Dimethyl-4,7-diphenyl-l,10- phenanthroline (BCP) and 3-(4-Biphenyl)-4-phenyl-5-tert-butylphenyl-l,2,4-triazole (TAZ), as well as those described in WO 2009080796 and WO 2009080797, both of which are incorporated herein by reference in their entireties.

Many suitable material for emissive layer in electroluminescence devices are known in the art. Host materials for the emissive layer include, for example, 4,4'-Bis(carbazol-9- yl)biphenyl (CBP) and ambipolar materials described in WO 2010149618, WO 2010149620, and WO 2010149622, all of which are incorporated herein by reference in their entireties. Guest materials for the emissive layer include, for example, Iridium complexes such as Tris(2-phenylpyridine)iridium(III) (Ir(ppy)₃), Tris(5 -phenyl- 10,10-dimethyl-4-aza- tricycloundeca-2,4,6-triene)Iridium(III) (Ir(pppy)₃) and Bis(3,5-difiuoro-2-(2-pyridyl)phenyl- (2-carboxypyridyl)iridium (III) (Flr(pic)), as well as Platinum complexes such as

platinum(II)[2-(4',6'-difluorophenyl)pyridinato-N,C )](2,4-pentanedionato) (F-Pt) and those described in WO 2011000873, which is incorporated herein by reference in its entirety.

The hole transport layer can be deposited on the anode from a solution. Alternatively, the hole transport layer can be formed from solution on a hole injection layer. The emissive layer can be deposited on the hole transport layer from a solution. The emissive layer can be vacuum vapor deposited on the hole transport layer.

The electroluminescence device can comprise a crosslinked hole transport layer, wherein the polymer in the hole transport layer can be, for example, thermally crosslinked or photochemically crosslinked. The crosslinking of the polymer of the hole transport layer can result in, for example, an insoluble organic layer resistant to degradation by solution processing of a subsequent layer from solution.

In some embodiments, the electroluminescence device comprises an emissive layer that comprises Ir(ppy)₃. The external quantum efficiency of such electroluminescence device at 1,000 cd/m can be, for example, at least 5%, or at least 8%, or at least 10%, or at least 12%, or at least 15%, or at least 18%, or at least 20%.

RAPID THERMAL PROCESSING (RTP)

RTP enables the fast curing of films. For example, after a film of the solution- processable crosslinking polymer described herein is solution deposited, said film can be heated at a temperature of 150 °C or more for 60 minutes or less, wherein the crosslinking polymer is crosslinked during the heating step. The RTP heating step can comprise, for example, heating the film at a temperature of 150 °C or more, or 200 °C or more, or 250 °C or more, or 300 °C or more, or 350 °C or more, or 400 °C or more. The RTP heating step can comprise, for example, ramping the temperature at a rate of 50 °C/minute or more, or 100 °C/minute or more, or 150 °C/minute or more, or 200 °C/minute or more, or 250 °C/minute or more. Further, the film can be cured by RTP at a temperature of 150 °C or more for, for example, 60 minutes or less, or 50 minutes or less, or 40 minutes or less, or 30 minutes or less, or 20 minutes or less.

Advantages of RTP include, for example, increasing throughput and minimizing the time that the material is subjected to high temperature. RTP has been described in, for example, Hisashi Fukuda, Rapid Thermal Processing for Future Semiconductor Devices 1-9 (2003).

In some embodiments, RTP allowed the films to be cured in only a few minutes. For example, films cured via the RTP process may only require about 10 minutes of heating time. Even when both the ambient purge and the cooling steps are taken into account, the total processing time for the process may be under 20 minutes, which is much faster than the four- hour hotplate bakes done previously. The RTP cured films have adequate solvent resistance to withstand typical spin coating conditions of upper layers {e.g., layers deposited directly on top of the RTP processed layer) of organic electronic devices. In one embodiment, the RTP process includes the following steps: 1) the polymer was spun-coated and dried on 90 °C hotplate for 5 min; 2) the RTP sample area was purged with N₂ for 3 min; 3) the temperature was ramped at 150 °C/min for 1.57 min; 4) the temperature was ramped at 50 °C/min. for 0.87 min; 5) the sample was maintained at 300 °C for 5 min; and 6) the sample was cooled from 300 °C to 180 °C for 2.25 min and from 180 °C to 100 °C for 9 min. The total processing time in said embodiment is 19.43 minutes.

EMBODIMENTS OF FIG 2

As shown in Figure 2, a polystyrene polymer is provided with a multicarbazole pendant group like structure I, wherein P is the polymer backbone and R can be other carbazole units, and the polymer also has thermally crosslinking groups. The crosslinking groups may be attached to one or more of the carbazoles of the multicarbazole pendant group or may be attached to another subunit of the polymer backbone. Each carbazole ring can be further substituted with halogens, alkyl, heteroalkyl groups (e.g., functional groups), aryl, or heteroaryl groups. Examples include a "triscarbazole" such as structure II or a "heptakiscarbazole" such as such as structure III. The multicarbazole pendant groups can sometimes be referred to as "dendrimers," where, for example, structure II would be a second generation dendrimer and structure III would be a third generation dendrimer. Each carbazole substituent may be substituted in the ortho, either meta, and/or para position relative to the nitrogen of the parent carbazole. Each dendrimer generation maybe have different ortho, meta, and/or para substitutions relative to the nitrogens of their parent compared to the substitution pattern of carbazoles in previous generations (e.g., the second generation carbazoles are substituted para to the first carbazole 's nitrogen and the third generation's carbazoles are substituted meta to the second generation's nitrogens). The ratio of multicarbazole pendant groups to crosslinking groups can be varied in the polymer to effect properties such as hole transport ability, processibility, mechanical stability, rate of crosslinking, etc. The polystyrene may also contain other groups such as electron

transporters, solubilizing groups, compatibilizing groups, crosslinking groups, etc. The styrene polymers may also be a copolymer with other backbone subunits.

WORKING EXAMPLES

Example 1 - Materials Synthesis

S3.1 : Synthesized according to the literature (Maegawa, Y.; Goto, Y.; Inagaki, S.; Shimada, T. Tetrahedron Letters. 2006, 47, 6957-6960). 1H NMR was consistent with the literature.

S3.2: To a solution of S3.1 (10.0 g, 23.87 mmol) and 11-bromo-l-undecanol (7.0 g, 28 mmol) in N,N-dimethyformamide (100.0 mL) was added K₂CO₃ (32.0 g, 230 mmol). The reaction was stirred at room temperature for 24 h. Deionized water (300 mL) was added. The precipitate was filtered. The crude product was purified by column chromatography (silica gel; hexanes:ethyl acetate = 7:3). 12.4 g (87.9 %) of a white product was obtained. 1H NMR (500 MHz, CDCI3) : δ 8.32 (d, J = 1.5 Hz, 2H), 7.71 (dd, J/ = 1.5 Hz, J₂ = 8.5 Hz, 2H), 7.16 (dd, J_/ = 1.5 Hz, J₂ = 8.5 Hz, 2H), 4.21 (t, J= 6.8 Hz, 2 H), 3.64 (m, 2 H), 3.41 (s, 1 H), 1.81 (m, 4 H), 1.54 (m, 4 H), 1.30 (m, 10 H). ¹³C{1H} (75 MHz, CDC1₃): 139.50, 134.48, 129.35, 123.96, 110.91, 81.77, 63.08, 43.24, 32.77, 29.48, 29.41, 29.39, 29.35, 29.30, 28.80, 27.18, 25.69. MS (EI) m/z : 588.9 [M+]. Anal, calcd. for C₂₃H₂₉I₂NO: C, 46.88; H, 4.96; N, 2.38. Found: C, 46.76; H, 5.10; N, 2.22.

S3.3: To a solution of S3.2 (8.0 g, 14 mmol), 9H-carbazole (6.8 g, 41 mmol) in dimethylsulfoxide (50.0 mL) were added Cu powder (10.0 g, 160 mmol) and Na₂C0₃ (30.0 g, 280 mmol). The reaction was stirred at 180 °C for 12 h. Insoluble inorganic salts were removed by filtration and washed with THF. After removal of THF, water (250 mL) was added. The precipitate was collected by filtration and purified by column chromatography (silica gel; toluene:ethyl acetate = 7:3). 8.1 g (91.0 %) of product was obtained as white solid. 1H (300MHz, CDCI₃): δ 8.24-8.13 (m, 5H), 7.71-7.63 (m, 4H), 7.43-7.22 (m, 13H), 4.49 (t, J = 6.98 Hz, 2H), 3.62 (t, J= 6.34 Hz, 2H), 2.05 (p, J= 7.28 Hz, 2H), 1.77-1.23 (m, 18H), 1.18 (s, 1H). ¹³C{1H} (75 MHz, CDCI₃): 5142.09, 140.42, 129.54, 126.19, 126.08, 123.62, 123.35, 123.33, 120.51, 120.07, 119.85, 110.34, 109.97, 63.31, 43.94, 33.02, 29.82, 29.79, 29.71, 29.66, 29.43, 27.66, 25.98. MS (EI) m/z : 667.4 [M+]. Anal, calcd. for C₄₇H₄₅N₃0: C, 84.52; H, 6.79; N, 6.29. Found: C, 84.37; H, 6.74; N, 6.29. )₂

S5.1 : In a round bottom flask, 4-bromobenzocyclobutene (1.509 g, 8.244 mmol) was dissolved in anhydrous diethyl ether (10.0 mL) under nitrogen atmosphere and the resulting solution was cooled at -78°C (dry-ice/acetone bath). To the cooled solution, 1.7M tert- butyllithium in pentane (6.0 mL, 10 mmol) was added dropwise. To the resulting pale yellow solution was then added 5.70 mL of trimethyl borate (0.80 M solution of in diethyl ether) and the reaction was stirred overnight. The solution was diluted through the addition of 10 mL of diethyl ether and the reaction was quenched by the addition of a dilute HC1 (aq) solution. The resulting solution was then washed twice with deionized water (2 x 15 mL) and dried over magnesium sulfate. The solvent was removed in vacuo to yield a viscous yellow oil (0.643 g, crude yield = 53.05%).¹H (300 MHz, CDC1₃): δ 6.89 (d, J = 7.7 Hz, 1H), 6.68-6.62 (m, 1H), 6.60-6.57 (m, 1H), 5.71 (br, 1H), 4.62 (br, 1H), 3.09 (s, 4H). [Intermediate was found to be consistent with a literature example of the target prepared by an alternate method (Yang, J.- X.; Ma, K.-Y.; Zhu, F.-H.; Chen, W.; Li, B.; Zhang, L.; Xie, R.-G. J. Chem. Res. 2005, 3, 184-186)].

S5.2: S5.1 (0.623 g, 4.21 mmol), deionized water (18.0 mL), and of 30% aq. hydrogen peroxide (0.88 mL) were mixed in a round bottom flask and the reaction was stirred at room temperature for 24 hours. It was observed that the starting material was only partially dissolved and 5mL of acetone were added to promote further dissolution and the reaction was allowed to proceed at room temperature for an additional 48 hours. The organic layer was then extracted with diethyl ether (30 mL), washed with deionized water (30 mL), and dried over magnesium sulfate. Solvent was removed in vacuo to yield a brown oil that was purified by column chromatography (silica gel ; hexanes:ethyl acetate 90: 10) to yield a yellow solid (0.194 g, 38.2%).1H (300 MHz, CDC1₃): δ 6.90 (d, J = 7.8 Hz, 1H), 6.65 (dd, J, = 7.8 Hz, J₂ = 2.1 Hz, 1H), 6.59 (d, J= 2.1Hz, 1H), 4.69 (s, 1H), 3.09 (s, 4H). Anal, calcd. for C₈H₈0: C, 79.97; H, 6.71. Found: C, 79.74; H, 6.77. [Intermediate was found to be consistent with a literature example of the target prepared by an alternate method (Tan, L.-S.; Venkatasubramanian, N. Synth. Commun. 1995, 25, 2189-2195)].

5.34: S5.2 (0.157 g, 1.31 mmol) was dissolved in N,N-dimethylformamide (20 mL) under nitrogen atmosphere, l-bromo-4-vinylbenzene (0.204 g, 1.34 mmol) was added dropwise and the resulting solution was cooled to 0 °C. NaH (0.095 g, 3.96 mmol) was then added over a five minute period, producing an intense yellow solution, which was stirred at room temperature overnight. The reaction was quenched by the addition of a saturated aq. NaCl solution (10 mL). The organic layer was extracted with diethyl ether (2 x 50 mL), washed with deionized water (40 mL), and dried over magnesium sulfate. Solvent was removed at reduced pressure to yield an off-white solid that was purified by column chromatography (silica gel; diethyl ether:hexanes 50:50) to yield a white solid (0.240 g, 77.4%). 1H (300

MHz, CDCI3 ): δ 7.42 (d, J = 8.4 Hz, 2H), 7.38 (d, J = 8.4 Hz, 2H), 6.94 (d, J = 8.1 Hz, 1H) 6.81 (dd, J = 8.0 Hz, J₂ = 2.1 Hz, 1H) 6.72 (dd, J = 17.4 Hz, J₂ = 11.1 Hz, 1H), 6.72 (d, J = 2.1 Hz, 1H), 5.75 (dt, J_l = 17.7 Hz, J₂ = 0.9 Hz, 1H), 5.25 (dt, J_l = 10.8 Hz, J₂ = 0.9 Hz, 1H), 5.017 (s, 2H), 3.10 (s, 4H). ¹³C{1H} (75 MHz, DMSO-^): δ 146.71, 137.96, 137.41, 136.70, 127.86, 126.61, 123.72, 114.48, 114.22, 110.0, 70.32, 29.24, 28.98. MS (EI) m/z = 236.2 [M+]. Anal, calcd. for Ci₇Hi₆0: C, 86. d: C, 86.68; H, 6.95.

S5.3: Triethylamine (3.266 g, 32.3 mmol), 3-ethyl-3-hydroxymethyl oxetane (3.018 g, 26.0 mmol), and toluene (30.0 mL) were combined under nitrogen atmosphere and cooled to 0 °C over an ice-water bath. Mesyl chloride (3.243 g, 28.3 mmol) was added to the reaction mixture dropwise over the period of 1 h while maintain the mixture at 0 °C. After 3 h, the reaction was filtered to remove the insoluble salt by-product. The organic phase was concentrated in vacuo to afford a clear lightly yellow colored oil (5.192 g). The product was not purified. 1H (300 MHz, CDC1₅): δ 4.47-4.42 (m, 4H), 4.38-4.36 (m, 2H), 3.06 (s, 3H), 1.80 (q, J= 7.5 Hz, 2H), 0.93 (t, J= 7.5 Hz, 3H). [Intermediate was prepared according to the patent literature (Hirotsu, K.; Takebayashi, K.; Kaneko, T. Patent JP 1999030490919991027, 2001; Hirotsu, K.; Murakami, T. Patent JP6137420070605, 2007)].

S5.4: Under nitrogen atmosphere, LiCl (1.207 g, 28.5 mmol) and anhydrous THF (20 mL) were combined and heated to 50 °C. S5.3 (5.192 g) was added into the heated solution dropwise over a period of 1 h. After 5 h, heating was stopped and toluene (50 mL) was added to the reaction flask. The organic layer was extracted with deionized water (3 x 30 mL) and the organic layer solvents were removed in vacuo to give a faintly yellow clear oil (2.105 g). The product was used without further purified. 1H (300 MHz, CDC1₅): δ 4.41 (s, 3H), 3.79 (s, 2H), 1.83 (q, J = 7.5 Hz, 2H), 0.89 (t, J = 7.5 Hz, 3H). [Intermediate was prepared according to the patent literature (Hirotsu, K.; Takebayashi, K.; Kaneko, T. Patent JP 1999030490919991027, 2001; Hirotsu, K.; Murakami, T. Patent JP6137420070605, 2007)].

5.36: 3-ethyl-3-((6-(4-vinylbenzyloxy)hexyloxy)methyl)oxetane (3.5 g, 14.9 mmol) was dissolved in anhydrous N,N-dimethylformamide (50 mL) under a nitrogen atmosphere and

NaH (0.724 g, 30.1 mmol) was added to the reaction in small portions. After three freeze- pump-thaw cycles the reaction mixture was heated to 50 °C and S5.4 (2.105 g, 15.6 mmol) was added to the reaction dropwise. The reaction was then heated to 90 °C. After 19 h, the reaction was diluted with ethyl acetate (100 mL) and then washed with deionized water (3 x

200 mL) to remove the DMF. The organic phase was dried over MgS0₄ and solvents were removed in vacuo to produce a brown colored oil. The oil was purified by column chromatography (silica gel, hexanes:ethyl acetate = 6:4) and concentrated to afford a lightly yellow oil (1.579 g, 31.8%). 1H (300 MHz, CDC/3): δ 7.41-7.37 (m, 2H), 7.30-7.27 (m, 2H),

6.71 (dd, J, = 17.6, J₂ = 10.9 Hz, 1H), 5.74 (dd, J = 17.6, J₂ = 0.9 Hz, 1H), 5.23 (dd, J =

10.9, J2 = 0.9 Hz, 1H), 4.58-4.31 (m, 6H), 3.51 (s, 2H), 3.45 (dt, J_l = 6.7, J₂ = 3.8 Hz, 4H), 1.75 (q, J = 7.5 Hz, 2H), 1.67-1.54 (m, 4H), 1.44-1.33 (m, 4H), 0.90 (t, J = 7.45 Hz, 3H). [Product was found to be consistent with a literature example of the target prepared by an alternate method (Bacher, E.; Bayerl, M. S.; Rudati, P.; Reckefuss, N.; Muller, C. D.; Meerholz, K.; Nuyken, O. Macr -1647)].

S5.6: Toluene (50 mL) was used to dissolve S3.3 (2.352 g, 3.52 mmol) in a flask. 50% aqueous sodium hydroxide (98.081 g) and tetrabutylammonium bromide (0.171 g, 0.53 mmol) were added to the flask. Under vigorous stirring, 4-vinylbenzyl chloride (0.601 g, 3.94 mmol) was added and the reaction was heated over an oil bath (50 °C). After one week, TLC analyses showed starting material was still present. Deionized water (100 mL) was added to the flask and diethyl ether was used to extract the product (3 x 100 mL). The ethereal layers were combined and solvents were removed in vacuo to give a yellow/orange crude product. The crude product was purified by silica gel column chromatography (hexanes/ethyl acetate - (8:2)) to give a white powder (1.156 g, 54%). 1H (300 MHz, CDC1₃): 58.19 (ddd, J, = 8.7, J? = 2.2 Hz, J₃ = 1.3 Hz, 5H), 7.67 (d, J = 0.99 Hz, 4H), 7.48-7.17 (m, 17H), 6.80-6.61 (m, 1H ), 5.81-5.65 (m, 1H), 5.29-5.16 (m, 1H), 4.57-4.41 (m, 4H), 3.44 (m, 2H), 2.04 (p, J = 7.1 Hz, 2H), 1.70-1.22 (m, 16H). ¹³C (75 MHz, CDCI₃): δ 142.1, 140.4, 138.6, 137.1, 136.8, 129.5, 128.1, 126.4, 126.2, 126.1, 123.6, 123.3m 120.5, 120.1, 119.9, 114.0, 110.4, 110.0, 72.3, 70.7, 43.9, 30.0, 29.8, 29.7, 29.4, 27.7, 26.5. MS (FAB) m/z = 783.3 [M+]. Anal, calcd. for C₅₆H₅3N₃0: C, 85.79; H, 6.81; N, 5.36. Found: C, 85.90; H, 6.72; N, 5.36.

5.33: Potassium vinyltrifluoroborate (1.428 g, 10.7 mmol), 4-bromo-l,2- dihydrocyclobutabenzene (1.507 g, 8.23 mmol), PdCl₂ (0.031 g, 0.18 mmol), triphenylphosphine (0.130 g, 0.50 mmol), and cesium carbonate (8.010 g, 24.6 mmol) were combined in a Schlenk tube under nitrogen atmosphere. A (9: 1) mixture of THF:water (15.0 mL) was added to the flask and the tube was sealed under nitrogen and stirred at 85 °C for 16 h. After cooling, the reaction mixture was mixed with deionized water (10 mL) and then extracted with dichloromethane (3 x 30 mL). The organic phase was dried over magnesium sulfate and filtered. Solvents were removed in vacuo to afford a dark colored oil that was purified by column chromatography (silica gel, 100% pentanes) to give a clear oil (0.591 g, 55.4%). 1H (300 MHz, CDC1₃): δ 7.23 (m, 1H), 7.19-7.13 (m, 1H), 7.05-6.98 (m, 1H), 6.78- 6.64 (m, 1H), 5.68 (dd, J = 17.57 Hz, J₂ = 0.99 Hz, 1H), 5.16 (dd, J = 10.86 Hz, J₂ = 0.98 Hz, 1H), 3.25-3.09 (m, 4H). [Intermediate was found to be consistent with a literature example of the target prepared by an alternate method (Blomberg, S.; Ostberg, S.; Harth, E.; Bosman, A. W.; Van Horn, B.; Hawker, C. J. J. Polym. Sci. A Polym. Chem. 2002, 40, 1309- 1320)].

5.37: S5.6 (0.263 g, 0.34 mmol), AIBN (0.0029 g, 0.018 mmol) and anhydrous tetrahydrofuran (2.4 mL) were combined in a Schlenk tube under nitrogen atmosphere. In a separate flask, 5.33 (0.0099 g, 0.08 mmol) was dissolved in anhydrous tetrahydrofuran (2.0 mL). The 5.33 solution (1.0 mL) was added to the reaction flask to give a 3.4 mL reaction volume. The mixture was subjected to freeze-pump-thaw (3 x) then placed under static nitrogen atmosphere and heated over an oil bath (60 °C). After 7 days, the solution was concentrated in vacuo and precipitated into acetone. The isolated polymer was re-precipitated into acetone (3 x) and then dried to produce a white powder (0.136 g, 51.0%). 1H (300 MHz, CDC1₃): δ 8.28-7.98 (br m, 5H), 7.73-7.11 (br m, 14H), 7.08-6.08 (br m, 5H), 4.58-4.10 (br m, 4H), 3.55-3.17 (br m, 2H), 3.11-2.90 (br m, 0.4H), 2.11-1.10 (br m, 18H). Elemental anal, calcd. for copolymer: C, 86.44; H, 6.90; N, 5.36. Found: C, 85.80; H, 6.69; N, 5.25. Gel Permeation Chromatograp 00; PDI = 3.38.

(target x = 0.9)

5.38: S5.6 (0.649 g, 0.828 mmol), 5.34 (0.0197 g, 0.0834 mmol), and AIBN (0.0070 mg) where dissolved in 8.0 mL anhydrous THF in a Schlenk tube. Freeze-pump-thaw (3 x) was performed and the tube was sealed under static nitrogen afterward. The reaction mixture was then stirred at 60 °C for 2 weeks. The reaction mixture was concentrated in vacuo, yielding a pale yellow oily solid that was dissolved in chloroform and precipitated into acetone to yield a white solid (0.555g, 82.8%). 1H (300MHz, CDCI3): δ 8.24-7.95 (br m, 5H), 7.68-7.09 (br m, 14H), 7.09-6.01 (br m, 0.4H), 4.53-4.02 (br m, 4H), 3.50-3.14 (br m, 2H), 3.00-2.87 (br m, 0.4H), 2.06-1.73 (br m, 3H), 1.52-0.84 (br m, 15H). Gel Permeation Chromatography (chloroform): M_w = 24,000; M_n = 10,200; PDI = 2.35. Anal, calcd. for copolymer: C, 85.80; H, 6.81; N, 5.20. Found: C, 85.28; H, 6.83; N, 5.14.

(target x = 0.9)

5.40: S5.6 (0.373 g, 0.48 mmol), AIBN (0.0027 g, 0.016 mmol) and anhydrous tetrahydrofuran (4.0 mL) were combined in a Schlenk tube under nitrogen atmosphere. In a separate flask, 5.36 (0.01662 g, 0.05 mmol) was dissolved in anhydrous tetrahydrofuran (1.0 mL). The 5.36 solution (1.0 mL) was added to the reaction flask to give a 5.0 mL reaction volume. The mixture was subjected to freeze-pump-thaw (3 x) then placed under static nitrogen atmosphere and heated over an oil bath (60 °C). After 7 days, the solution was concentrated in vacuo and precipitated into acetone. The isolated polymer was re-precipitated into acetone (3 x) and then dried to produce a white powder (0.223 g, 57.0%). 1H (300 MHz, CDC ): δ 8.26-8.00 (br m, 5H), 7.69-7.11 (br m, 14H), 7.08-6.18 (br m, 5H), 4.55-4.12 (br m, 4H), 3.57-3.26 (br m, 2.2H), 2.10-0.78 (br m, 18H). Gel Permeation Chromatography (chloroform): M_w = 25,700; M_n = 7,400; PDI = 3.45. Anal, calcd. for copolymer: C, 84.80; H, 7.10; N, 5.36. Found: C, 84.40; H, 6.86; N, 5.27.

(target x = 0.7)

5.41: S5.6 (0.294 g, 0.37 mmol), AIBN (0.0036 g, 0.02 mmol) and anhydrous tetrahydrofuran (3.0 mL) were combined in a Schlenk tube under nitrogen atmosphere. In a separate flask, 5.36 (0.052 g, 0.15 mmol) was dissolved in anhydrous tetrahydrofuran (1.0 mL). The 5.36 solution (1.0 mL) was added to the reaction flask to give a 4.0 mL reaction volume. The mixture was subjected to freeze-pump-thaw (3 x) then placed under static nitrogen atmosphere and heated over an oil bath (60 °C). After 7 days, the solution was concentrated in vacuo and precipitated into acetone (20 mL). The isolated polymer was re-precipitated into acetone (3 x) and then dried to produce a white powder (0.168 g, 47.9%). ¹H (300 MHz, CDC ): δ 8.26-8.00 (br m, 5H), 7.69-7.11 (br m, 14H), 7.08-6.18 (br m, 5H), 4.55-4.12 (br m, 4H), 3.57-3.26 (br m, 2.2H), 2.10-0.78 (br m, 18H). Gel Permeation Chromatography (chloroform): M_w = 12,700; M_n = 7,500; PDI = 1.7. Anal, calcd. for copolymer: C, 82.88; H, 7.60; N, 3.75. Found: C, 83.87; H, 7.10; N, 4.75. [Elemental analysis data suggests that the ratio may be closer to x = 0.8].

(6-(9H-carbazol-9-yl)-9-(4-vinylbenzyl)- 9H-3,9'-bicarbazole)

Triscarbazole monomer (6-(9H-carbazol-9-yl)-9-(4-vinylbenzyl)-9H-3,9'-bicarbazole):

To a solution of Triscarbazole (3.0 g, 6.03 mmol) and l-(chloromethyl)-4-vinylbenzene (1.5 g, 9.83 mmol) in DMF (40.0 ml) was added K₂CO₃ (10 g, 72.36 mmol) at room temperature under stirring. The reaction was carried out at room temperature for 52 h. Water (200.0 ml) was added. The white solid product was obtained by filtration, washed with water and methanol. After dry, the crude product was purified by silica gel column chromatography using dichloromethane/hexanes (6:4) as eluent. After removal of solvent, the white solid product was obtained and collected from hexanes by filtration. After vacuum dry, the product was collected as a white solid in 3.55 g (95.9%) yield.

1H NMR (400 MHz, CDCI₃) δ 8.25 (s, 2 H), 8.17 (d, J= 8.0 Hz, 4 H), 7.63 (d, J= 1.2 Hz, 4 H), 7.44-7.37 (m, 10 H), 7.30-7.26 (m, 6 H), 6.72 (dd, J = 17.6 Hz, J₂ = 10.8 Hz, 1 H, C=C-H), 5.76 (d, J = 17.6 Hz, 1 H, C=C-H), 5.68 (s, 2 H, NCH₂), 5.27 (d, J = 10.8 Hz, 1 H, C=C-H) ppm. ¹³C NMR (100 MHz, CDC1₃) δ 141.76, 140.34, 137.32, 136.16, 135.99, 129.79, 126.86, 126.79, 126.16, 125.84, 123.62, 123.10, 120.26, 119.83, 119.64, 114.33, 110.33, 109.71, 46.96 ppm. MS-EI (m/z): [M]⁺ calcd for C₄₅H₃₁N₃, 613.3, 614.3, 615.3, 616.3, found 613.2, 614.2, 615.2, 616.2. Anal. Calcd for C₄₅H₃₁N₃: C, 88.06; H, 5.09; N, 6.85. Found: C, 87.15; H, 5.03; N, 6.50.

Poly(6-(9H-carbazol-9-yl)-9-(4- vinylbenzyl)-9/-/-3, 9' -bicarbazole)

Poly(triscarbazole) (Polymer A, Poly(6-(9H-carbazol-9-yl)-9-(4-vinylbenzyl)-9H-3,9'- bicarbazole)): A Schlenk flask was charged with tris-carbazole monomer 6-(9H-carbazol-9- yl)-9-(4-vinylbenzyl)-9H-3,9'-bicarbazole (1.0 g, 1.6 mmol), AIBN (7.0 mg, 0.042 mmol) and dry THF (20.0 ml). The polymerization mixture was purged with nitrogen (removal of oxygen), securely sealed under nitrogen, and heated to 60°C. The polymerization was carried out at 60°C with stirring for 7 days. After cooling to room temperature, the polymer was precipitated with acetone. The white polymer precipitate was collected by filtration, dissolved in dichloromethane, and precipitated with acetone again. This dissolution/precipitation procedure was repeated three more times. The collected polymer was dried under vacuum. After vacuum dry, the polymer as white solid in 0.93 g (93.0 %) was obtained.

Example 2

G ass

Indium tin oxide (ITO)-coated glass slides (Colorado Concept Coatings LLC) with a sheet resistivity of -15 Ω/sq were used as substrates for the OLEDs fabrication. The ITO substrates were masked with kapton tape and the exposed ITO was etched in acid vapor (1 :3 by volume, HNO₃: HC1) for 5 min at 60 °C. The substrates were cleaned in an ultrasonic bath in the following solutions: detergent water, distilled water, acetone, and isopropanol for 20 min in each step. At the end the substrates were blown dry with nitrogen. Subsequently, ITO substrates were 0₂ plasma treated for 2 min.

Polymer 5.38 was processed in the glove box under nitrogen. 10 mg of Polymer 5.38 was dissolved in 1ml of anhydrous chlorobenzene (Aldrich). 35 nm thick films of the hole- transport material were spin-coated at 1000 rpm, acceleration 1540 rpm/sec for 60 sec. The films were then dried on a hot plate at 110 °C for 30 minutes followed by thermal curing at 300 °C for 10 min. A watch glass was used during the curing process over the samples in order to avoid excessive heat loses.

Emissive layer, consisting of a host - CBP (Aldrich) and an emitter - Ir(ppy)3 (Lumtec) was deposited by co-evaporation of the two components at 0.94 A/s and 0.06 A/s respectively. The electron transport layer, BCP (Aldrich), the electron-injection layer, LiF (Aldrich),aluminum and silver were thermally evaporated at 1 A/s, 0.2 A/s, 2 A/s and 2 A/s respectively. The pressure in the vacuum chamber was l x lO^"7 Torr. The active area of the tested devices was about 0.1 cm . The devices were tested in a glove box under nitrogen.

As shown in Figure 3, OLED devices with Polymer 5.38 spin-coated as the hole transport layer, as well as evaporation-deposited CBP: Ir(ppy)3 emitting layer, are capable of achieving high external quantum efficiencies. Example 3

6

Glass

Indium tin oxide (ITO)-coated glass slides (Colorado Concept Coatings LLC) with a sheet resistivity of -15 Ω/sq were used as substrates for the OLEDs fabrication. The ITO substrates were masked with kapton tape and the exposed ITO was etched in acid vapor (1 :3 by volume, HNO3: HC1) for 5 min at 60 °C. The substrates were cleaned in an ultrasonic bath in the following solutions: detergent water, distilled water, acetone, and isopropanol for 20 min in each step. At the end the substrates were blown dry with nitrogen. Subsequently, ITO substrates were 0₂ plasma treated for 2 min.

Emissive layer, consisting of a polymer blend and emitter was prepared in the following way in the glove box: 10 mg of Polymer A in 1 ml chlorobenzene, 10 mg of Polymer B in 1 ml of chlorobenzene and 10 mg of Ir(pppy)₃ (Solvay) in 1 ml of chlorobenzne. The solutions of the polymers were then mixed together (1ml of each) to which 128 μΐ of Ir(pppy)₃ was added. The mixture was spin-coated at 2000 rpm, 1000 rpm / sec, 60 sec and dried on hot plate at 120 °C for 10-15 min.

The electron transport layer, BCP (Aldrich), the electron-injection layer, LiF (Aldrich), aluminum and silver were thermally evaporated at 1 A/s, 0.2 A/s, 2 A/s and 2 A/s respectively. The pressure in the vacuum chamber was l x lO^"7 Torr. The active area of tested ox under nitrogen.

(Polymer B)

As shown in Figure 4, OLED devices with Polymer 5.38 spin-coated as the hole transport layer, as well as spinning-coated emitting layer, are capable of achieving high external quantum efficiencies. In summary, devices having hole transport layers comprising the crosslinking hole transport polymers with triscarbazole pendant groups are suitable as HTLs for solution processing of subsequent layers. Based on the respective hole mobility, various polymers can be suitable in different device architectures and/or with different materials in the other devices layers to modify the balance of charge and increase efficiency.

Example 4

Polymer 5.38 was processed in the glove box under nitrogen. 10 mg of Polymer 5.38 was dissolved in 1ml of anhydrous chlorobenzene (Aldrich). 35 nm thick films of the hole- transport material were spin-coated at 1000 rpm, acceleration 1540 rpm/sec for 60 sec. The films were then dried on a hot plate at 110 °C for 30 minutes followed by thermal curing by RTP at 300 °C for 5 min. The RTP procedure temperature profile is presented in Figure 5(A).

Emissive layer, consisting of a host - CBP (Aldrich) and an emitter - Ir(ppy)3 (Lumtec) was deposited by co -evaporation of the two components at 0.94 A/s and 0.06 A/s respectively. The electron transport layer, BCP (Aldrich), the electron-injection layer, LiF (Aldrich), aluminum and silver were thermally evaporated at 1 A/s, 0.2 A/s, 2 A/s and 2 A/s respectively. The pressure in the vacuum chamber was 1 x 10^"7 Torr. The active area of the tested devices was about 0.1 cm . The devices were tested in a glove box under nitrogen. The performance of the device is shown in Figure 5(B)-(C). Example 5

6

Glass

Polymer 5.38 was processed in the glove box under nitrogen. 10 mg of Polymer 5.38 was dissolved in 1ml of anhydrous chlorobenzene (Aldrich). 35 nm thick films of the hole- transport material were spin-coated at 1000 rpm, acceleration 1540 rpm/sec for 60 sec. The films were then dried on a hot plate at 110 °C for 30 minutes followed by thermal curing by RTP at 300 °C for 5 min. The RTP procedure temperature profile is presented in Figure 6(A).

Emissive layer, consisting of a polymer blend and emitter was prepared in the following way in the glove box: 10 mg of Polymer A in 1 ml chlorobenzene, 10 mg of Polymer B in 1 ml of chlorobenzene and 10 mg of Ir(pppy)₃ (Solvay) in 1 ml of

chlorobenzene. The solutions of the polymers were then mixed together (1ml of each) to which 128 μΐ of Ir(pppy)₃ was added. The mixture was spin-coated at 2000 rpm, 1000 rpm / sec, 60 sec and dried on hot plate at 120 °C for 10-15 min.

The electron transport layer, BCP (Aldrich), the electron-injection layer, LiF

(Aldrich), aluminum and silver were thermally evaporated at 1 A/s, 0.2 A/s, 2 A/s and 2 A/s respectively. The pressure in the vacuum chamber was 1 x 10^"7 Torr. The active area of the tested devices was about 0.1 cm . The devices were tested in a glove box under nitrogen. The performance of the device is shown in Figure 6(B)-(C).

Example 6

A device is fabricated in substantially the same way as in Example 2, except that the hole transport layer comprises Polymer 5.40 instead of Polymer 5.38. The performance of the device is shown in Figure 7.

Polymer 5.40 was processed in the glove box under nitrogen. 5 mg of TAG (4- isopropyl-4'-methyldiphenyl iodonium tetrakis(pentafluorophenyl)borate) (DPI-TPFPB) (Aldrich) was dissolve in 10 ml of anhydrous chlorobenzene (Aldrich) then 10 mg of Polymer 5.40 was dissolved in 1ml of previously prepared TAG solution. Around 35 nm thick films of the hole-transport material were spin-coated at 1000 rpm, acceleration 1540 rpm/sec for 60 sec. The films were then dried on a hot plate at 110 °C for 30 minutes followed by thermal curing at 200 °C for 30 min. A watch glass was used during the curing process over the samples in order to avoid excessive heat loses.

Example 7

LiF/AI/Ag (2.5/60 nm/100 nm)

BCP (50 nm)

1 : 1 Polymer A: Polymer B - lr(pppy)₃ 6

wt%

Polymer 5.40 (35 nm)

ITO

Glass

A device is fabricated in substantially the same way as in Example 3, except that the hole transport layer comprises Polymer 5.40 instead of Polymer 5.38. The performance of the device is shown in Figure 8.

Polymer 5.40 was processed in the glove box under nitrogen. 5 mg of TAG (DPI- TPFPB) (Aldrich) was dissolve in 10 ml of anhydrous chlorobenzene (Aldrich) then 10 mg of Polymer 5.40 was dissolved in 1ml of previously prepared TAG solution. Around 35 nm thick films of the hole-transport material were spin-coated at 1000 rpm, acceleration 1540 rpm/sec for 60 sec. The films were then dried on a hot plate at 110 °C for 30 minutes followed by thermal curing at 200 °C for 30 min. A watch glass was used during the curing process over the samples in order to avoid excessive heat loses.

Example 8

A device is fabricated in substantially the same way as in Example 4, except that the hole transport layer comprises Polymer 5.40 instead of Polymer 5.38. The performance of the device is shown in Figure 9(B)-(C).

Polymer 5.40 was processed in the glove box under nitrogen. 5 mg of TAG (DPI- TPFPB) (Aldrich) was dissolved in 10 ml of anhydrous chlorobenzene (Aldrich) then 10 mg of Polymer 5.40 was dissolved in 1 ml of previously prepared TAG solution. Around 35 nm thick films of the hole-transport material were spin-coated at 1000 rpm, acceleration 1540 rpm/sec for 60 sec. The films were then dried on a hot plate at 110 °C for 30 minutes followed by thermal curing by RTP at 200 °C for 30 min. The RTP procedure temperature profile is presented in Figure 9(A).

Example 9

A device is fabricated in substantially the same way as in Example 5, except that the hole transport layer comprises Polymer 5.40 instead of Polymer 5.38. The performance of the device is shown in Figure 10(B)-(C).

Polymer 5.40 was processed in the glove box under nitrogen. 5 mg of TAG (DPI- TPFPB) (Aldrich) was dissolve in 10 ml of anhydrous chlorobenzene (Aldrich) then 10 mg of Polymer 5.40 was dissolved in 1 ml of previously prepared TAG solution. Around 35 nm thick films of the hole-transport material were spin-coated at 1000 rpm, acceleration 1540 rpm/sec for 60 sec. The films were then dried on a hot plate at 110 °C for 30 minutes followed by thermal curing by RTP at 200 °C for 30 min. The RTP procedure temperature profile is presented in Figure 10(A). Example 10

G ass

A device is fabricated in substantially the same way as in Example 7, except that the emissive layer host comprises Compound XI instead of Polymer A:Polymer B blend. The performance of the device is shown in Figure 11.

Emissive layer, consisting of the Compound XI host and emitter was prepared in the following way in the glove box: 10 mg of Compound XI was dissolved in 1 ml

chlorobenzene and 10 mg of Ir(pppy)₃ (Solvay) in 1 ml of chlorobenzne. 64 μΐ of Ir(pppy)₃ was added to 1 ml of the solution of Compound XI . The solution was then spin-coated onto the HTL at 2000 rpm, 1000 rpm / sec, 60 sec. The films were dried at 100 °C for 10-15 min.

Example 11

G ass A device is fabricated in substantially the same way as in Example 10, except that a PEDOT:PSS hole injection layer was deposited between the ITO substrate and the Polymer 5.40 hole transport layer. The performance of the device is shown in Figure 12.

Immediately after 0₂ plasma treatment of the ITO slides, PEDOT:PSS AI4083 (Clevios) was spin-coated at 5000 rpm, acceleration - 928 rpm/s for 60 sec. Subsequently, the films were heated on a hot plate at 140°C for 15 min. PEDOT:PSS was deposited in air.

Example 12

G ass

A device is fabricated in substantially the same way as in Example 11 , except that the emissive layer host comprises Compound X2 instead of Compound XI . The performance of the device is shown in Figure 13.

Example 13

LiF/AI/Ag (2.5/60 nm/100 nm)

BCP (50 nm)

Compound X2:lr(pppy)₃ 6 wt. % (20

nm)

Polymer 5.40 (35 nm)

ITO

Glass

A device is fabricated in substantially the same way as in Example 10, except that the emissive layer host comprises Compound X2 instead of Compound XI . The performance of the device is shown in Figure 14.

Example 14

ass

A device is fabricated in substantially the same way as in Example 10, except that the emissive layer host comprises Compound X3 instead of Compound XI . The performance of the device is shown in Figure 15.

Example 15 LiF/AI/Ag (2.5/60 nm/100 nm)

BCP (50 nm)

Compound X3:lr(pppy)₃ 6 wt. % (20

nm)

Polymer 5.40 (35 nm)

PEDOT: PSS Al 4083 (50 nm)

ITO

Glass

A device is fabricated in substantially the same way as in Example 11 , except that the emissive layer host comprises Compound X3 instead of Compound XI . The performance of the device is shown in Figure 16.

Example 16

LiF/Al/Ag (2.5/60 nm/100 nm)

BCP {50 nm)

. Compound Yl:lr{pppy)₅ 6 wt. % (20

nm)

Polymer 5.40 (35 nm)

PEDOT: PSS Al 4083 (50 nm)

\TO

^■ Glass

A device is fabricated in substantially the same way as in Example 11 , except that the emissive layer host comprises Compound Yl instead of Compound XI . The performance of the device is shown in Figure 17.

Emissive layer, consisting of the Compound Yl host and emitter was prepared in the following way in the glove box: 10 mg of Compound Yl was dissolved in 1 ml

chlorobenzene and 10 mg of Ir(pppy)₃ (Solvay) in 1 ml of chlorobenzne. 64 μΐ of Ir(pppy)₃ was added to 1 ml of the solution of Compound Yl . The solution was then spin-coated onto the HTL at 2000 rpm, 3000 rpm / sec, 60 sec. The films were dried at 100 °C for 5 min. Example 17

Glass

A device is fabricated in substantially the same way as in Example 11 , except that the emissive layer host comprises Compound Y2 instead of Compound XI . The performance of the device is shown in Figure 18.

Emissive layer, consisting of the Compound Y2 host and emitter was prepared in the following way in the glove box: 10 mg of Compound Y2 was dissolved in 1.5 ml toluene and 10 mg of Ir(pppy)₃ (Solvay) in 1.0 ml of toluene. 60 μΐ of Ir(pppy)₃ was added to 1 ml of the solution of Compound Y2. The solution was then spin-coated onto the HTL at 2000 rpm, 1000 rpm / sec, 60 sec. The films were dried at 100 °C for 5 minutes.

Example 18

A device is fabricated in substantially the same way as in Example 11 , except that the emissive layer host comprises Compound Y3 instead of Compound XI . The performance of the device is shown in Figure 19. Emissive layer, consisting of the Compound Y3 host and emitter was prepared in the following way in the glove box: 10 mg of Compound Y3 was dissolved in a mixture of 1 ml chlorobenzene and 1 ml of DMF, 10 mg of Ir(pppy)₃ (Solvay) was dissolved in 1 ml of chlorobenzne. 64 μΐ of Ir(pppy)₃ was added to 1 ml of the solution of Compound Y3. The solution was then spin-coated onto the HTL at 2000 rpm, 3000 rpm / sec, 60 sec. The films were dried at 100 °C for 5 minutes.

A device is fabricated in substantially the same way as in Example 11 , except that the emissive layer host comprises Compound Y4 instead of Compound XI . The performance of the device is shown in Figure 20.

Emissive layer, consisting of the Compound Y4 host and emitter was prepared in the following way in the glove box: 10 mg of Compound Y4 was dissolved in mixture of 1 ml toluene and 0.5 ml of acetonitrile, and 10 mg of Ir(pppy)₃ (Solvay) in 1 ml of toluene. 60 μΐ of Ir(pppy)₃ was added to 1 ml of the solution of Compound Y4. The solution was then spin- coated onto the HTL at 2000 rpm, 1000 rpm / sec, 60 sec. The films were dried at 100 °C for 5 minutes.

Example 20 LfF/Af/Ag (2.5/60 nm/IOO nm}

BCP (50 nm)

Compound Y4:ir{pppy)₃ 6 wt. % (20

nm)

Polymer 5.40 (35 nm)

MoO, (15 nm)

no

A device is fabricated in substantially the same way as in Example 19, except that the hole injection layer host comprises M0O3 instead of PEDOT:PSS. The hole injection layer, M0O3 (Aldrich), was thermally evaporated at 0.2 A/s. The pressure in the vacuum chamber was 1 x 10^"7 Torr. The performance of the device is shown in Figure 21.

Example 21

A device is fabricated in substantially the same way as in Example 11 , except that the emissive layer host comprises Compound Y5 instead of Compound XI . The performance of the device is shown in Figure 22.

Emissive layer, consisting of the Compound Y5 host and emitter was prepared in the following way in the glove box: 10 mg of Compound Y5 was dissolved in 1.5 ml toluene and 10 mg of Ir(pppy)₃ (Solvay) in 1.0 ml of toluene. 60 μΐ of Ir(pppy)₃ was added to 1 ml of the solution of Compound Y5. The solution was then spin-coated onto the HTL at 2000 rpm, 1000 rpm / sec, 60 sec. The films were dried at 100 °C for 5 minutes. Example 22

A device is fabricated in substantially the same way as in Example 21, except that the hole injection layer host comprises M0O₃ instead of PEDOT:PSS. The hole injection layer, M0O₃ (Aldrich), was thermally evaporated at 0.2 A/s. The pressure in the vacuum chamber was 1 x 10^"7 Torr. The performance of the device is shown in Figure 23.

Claims

WHAT IS CLAIMED IS:

1. A composition comprising at least one polymer comprising one or more crosslinking groups, said polymer comprising one or more type (I) subunits represented by formula (I) and optionally one or more type (II) subunits represented by formula (II):

wherein:

X, Y, and Z are each independently H, alkyl, F or fluoroalkyl; XL is a crosslinking group; and

TCz is an organic group comprising at least one optionally substituted triscarbazole group linked to a linker group, said triscarbazole group optionally comprises one or more crosslinking groups.

2. The composition of claim 1, wherein TCz is represented by formula (III) or formula

wherein:

L is an linker group;

Rl, R2, R3, and R4 are each independently a hydrogen, a halogen, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted heteroalkyl group, or an optionally substituted heteroaryl group; XL, XL1, XL2, XL3, and XL4 are each independently a crosslinking group; and

kl, k2, k3, and k4 are each 0, 1 or 2.

3. The composition of claims 1 - 2, wherein the type (I) subunits do not comprise crosslinking groups and wherein the type (I) subunits and the type (II) subunits are arranged as a block copolymer.

4. The composition of claims 2 and 3, wherein Rl, R2, R3, and R4 are each a hydrogen.

5. The composition of claims 2 and 3, wherein at least one of Rl, R2, R3, and R4 comprises an optionally substituted carbazole group.

6. The composition of claims 2 and 3, wherein Rl, R2, R3, and R4 each comprises an optionally substituted carbazole group.

7. The composition of claims 2 and 3, wherein L is an optionally substituted alkylene group, an optionally substituted arylene group, an optionally substituted

heteroalkylene group, or an optionally substituted heteroarylene group.

8. The composition of claim 7, wherein L is an alkylene group, an oxyalkylene group, an oligo-oxyalkylene group, an oxyarylene group, a carbonyl alkylene group, a carbonyl arylene group, a carboxyl alkylene group, a carboxyl arylene group, an ether group, an ester group, or a ketone group.

9. The composition of claims 2 and 3, wherein L does not comprise a 2-phenyl- 5-phenyl-l,3,4-oxadiazole group.

10. The composition of claim 2, wherein the type (II) subunits are present and kl, k2, k3, and k4 are each 0.

11. The composition of claim 2, wherein the type (II) subunits are absent, and at least one of kl, k2, k3, and k4 is not 0.

12. The composition of claims 1 - 3, wherein the crosslinking groups each comprise a reactive group optionally linked to a linker group.

13. The composition of claims 2 and 3, wherein the crosslinking groups each comprise a reactive group optionally linked to a linker group, wherein the linker group is an optionally substituted alkylene group, an optionally substituted arylene group, an optionally substituted heteroalkylene group, or an optionally substituted heteroarylene group.

14. The composition of claims 2 and 3, wherein the crosslinking groups each comprise a reactive group optionally linked to a linker group, wherein the reactive groups are selected from one or several groups consisting of:

wherein R' is a hydrogen, a halogen, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted heteroalkyl group, or an optionally substituted heteroaryl group; and

wherein R" is a hydrogen, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted heteroalkyl group, or an optionally substituted heteroaryl group.

15. The composition of claim 2, wherein TCz is represented by formula (V), formula (VI), formula (VII), or formula (VIII):

16. The composition of claims 1 - 3, wherein both the type (I) subunits and the type (II) subunits are present, the type (I) subunits are represented by formula (IX) or formula (X), and the type (II) subunits are represented by formula (XI):

(XI)

17. The composition of claims 1 - 3, wherein both the type (I) subunits and the type (II) subunits are present,

wherein the type (I) subunits are selected from one or several groups consisting of:

wherein the type (II) subunits are selected from one or several groups consisting of:

wherein n = 0 - 20, R' is a hydrogen, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted heteroalkyl group, or an optionally substituted heteroaryl group.

18. The composition of claim 1, wherein the type (II) subunits are absent, and wherein the polymer is a homopolymer.

19. The composition of claim 1 , wherein the polymer is a copolymer.

20. The composition of claims 1 - 3, wherein the polymer is a copolymer, and wherein the type (I) subunits are present at a molar fraction of 0.5-0.99.

21. The composition of claims 1 - 3, wherein the polymer is a copolymer, and wherein the type (I) subunits are present at a molar fraction of 0.7-0.9.

22. The composition of claims 1 - 3, wherein the polymer is a copolymer that further comprises in the polymer backbone one or more type (III) subunits.

23. The composition of claims 1 - 3, wherein the polymer is a copolymer that further comprises in the polymer backbone one or more type (III) subunits each comprising one or more moieties selected from the group consisting of electron transporters, solubilizing groups, compatibilizing groups, and crosslinking groups.

24. The composition of claim 12, wherein the polymer is a copolymer that further comprises in the polymer backbone one or more type (III) subunits each comprising at least one crosslinking group, said crosslinking group comprises at least one reactive group having similar reactivity to the reactive groups of the type (II) subunits.

25. The composition of claims 1 - 3, wherein the type (I) subunits comprise one or more moieties selected from the group consisting of electron transporter, solubilizing groups, and compatibilizing groups.

26. The composition of claims 1 - 3, wherein the type (II) subunits comprises one or more moieties selected from the group consisting of electron transporter, solubilizing groups, and compatibilizing groups

27. The composition of claim 1, wherein the polymer has a weight average molecular weight Mw of 10,000 Da or more, and at least 5 crosslinking groups per macromolecule.

28. The composition of claim 1, wherein the type (I) subunits do not comprise any 2-phenyl-5 -phenyl- 1, 3, 4-oxadiazole moeity.

29. A composition comprising at least one polymer comprising at least one crosslinking group, said polymer comprising at least one type (I) subunit represented by formula (XII) or formula (XIII) and optionally at least one type (II) subunit represented by formula (XIV):

wherein XL is a crosslinking group; and

30. A hole transport layer, comprising the composition of claim 1, wherein the polymer is crosslinked.

31. A hole injection layer, comprising the composition of claim 1 and a p-dopant, wherein the polymer is crosslinked.

32. The hole injection layer of claim 31 , wherein the dopant is a soluble complex of Mo(VI) or Cr(VI).

33. An electroluminescence device, comprising at least an anode, a cathode, an emissive layer, and the hole transport layer of claim 30.

34. An electroluminescence device, comprising at least an anode, a cathode, an emissive layer, the hole injection layer of claims 31-32 and the hole transport layer of claim 30.

35. The electroluminescence devices of claims 33-34, wherein the hole injection layer and the hole transport layer are solution deposited on the anode.

36. The electroluminescence device of claims 33-34, wherein the polymer in the hole injection and hole transport layer is thermally crosslinked.

37. The electroluminescence device of claims 33-34, wherein the polymer in the hole injection and hole transport layer is photochemically crosslinked.

38. The electroluminescence device of claims 33-34, wherein the emissive layer comprises at least one phosphorescent emitter, and wherein the external quantum efficiency of the electroluminescence device at 1,000 cd/m is least 5%.

39. The electroluminescence device of claims 33-34, wherein the emissive layer comprises at least one phosphorescent emitter, and wherein the external quantum efficiency of the electroluminescence device at 1,000 cd/m is least 10%.

40. A method for making an electroluminescence device, comprising:

providing an anode layer;

depositing the hole transport layer of claim 30 from solution onto the anode layer; and crosslinking the polymer to produce a crosslinked hole transport layer, wherein the crosslinked hole transport layer is substantially insolubilized.

41. A method for making an electroluminescence device, comprising:

providing an anode layer;

depositing the hole injection layer of claims 31-32 from solution onto the anode layer;

crosslinking the polymer to produce a crosslinked hole injection layer, wherein the crosslinked hole injection layer is substantially insolubilized;

depositing the hole transport layer of claim 30 from solution onto the hole injection layer; and

crosslinking the polymer to produce a crosslinked hole transport layer, wherein the crosslinked hole transport layer is substantially insolubilized.

42. The method of claims 40-41, further comprising depositing an emissive layer from solution onto the crosslinked hole transporting layer.

43. A method for making an electroluminescence device, comprising:

(i) providing a conductive substrate;

(ii) depositing a composition onto the substrate to form a layer, said composition comprising at least one polymer comprising one or more crosslinking groups, said polymer comprising one or more type (I) subunits represented by formula (I) and optionally one or more type (II) subunits represented by formula (II):

wherein: X, Y, and Z are each independently H, alkyl, F or fluoroalkyl; XL is a crosslinking group; TCz is an organic group comprising at least one optionally substituted triscarbazole group linked to a linker group, said triscarbazole group optionally comprises one or more crosslinking groups; and the polymer comprises one or more crosslinking groups; and (iii) rapidly heating said layer at a temperature of 150 °C or more for 60 minutes or less, wherein the polymer is crosslinked after said heating step.

44. The method of claim 43, wherein the rapid heating step comprises heating the layer at a temperature not more than 30°C above the glass temperature of the polymer comprising radiatively activable crosslinking groups.

45. The method of claims 43-44, wherein the rapid heating step comprises ramping the temperature at a rate of 100 °C/minute or more.

46. The method of claims 43-44, wherein the rapid heating step comprises heating the layer at a temperature of 150 °C or more for 30 minutes or less.

47. A crosslinked film obtained by thermally or photochemically crosslinking a composition comprising at least one polymer comprising one or more crosslinking groups, said polymer comprising one or more type (I) subunits represented by formula (I) and optionally one or more type (II) subunits represented by formula (II):

wherein:

X, Y, and Z are each independently H, alkyl, F or fluoroalkyl;

XL is a crosslinking group; and