Charge transporting semi-conducting material and semi-conducting device

Abstract

The present invention relates to a charge transporting semi-conducting material comprising: a) optionally at least one electrical dopant, and b) at least one cross-linked charge-transporting polymer comprising 1,2,3-triazole cross-linking units, a method for its preparation and a semiconducting device comprising the charge transporting semi-conducting material.

Claims

1. A charge transporting semi-conducting material comprising: a cross-linked charge-transporting polymer comprising 1,2,3-triazole cross-linking units of the general formulae Ia and/or Ib, ##STR00074## wherein aa) Pol.sup.1-Pol.sup.4 are independently selected from charge-transporting polymers, bb) X.sup.1, X.sup.2, X.sup.3, and X.sup.4 are independently selected from spacer units having up to 30 multivalent atoms or represent direct bonding of Pol.sup.1-Pol.sup.4 to the 1,2,3-triazole ring, and cc) R and R′ are independently selected from the group consisting of H, halogen, nitrile, C.sub.1-C.sub.22 saturated or unsaturated alkyl, C.sub.3-C.sub.22 cycloalkyl, C.sub.6-C.sub.18 aryl, C.sub.7-C.sub.22 arylalkyl, C.sub.2-C.sub.13 heteroaryl having up to three heteroatoms independently selected from oxygen, nitrogen, or sulphur, SiR.sup.1R.sup.2R.sup.3, wherein R.sup.1, R.sup.2, and R.sup.3 are independently selected from C.sub.1-C.sub.4 alkyl or phenyl, COR.sup.4 or COOR.sup.5, wherein R.sup.4 and R.sup.5 are independently selected from C.sub.1-C.sub.22 alkyl or C.sub.7-C.sub.22 arylalkyl, and CR.sup.6R.sup.7OR.sup.8, wherein R.sup.6 and R.sup.7 are independently selected from H, C.sub.1-C.sub.6 alkyl, C.sub.6-C.sub.9 aryl, or R.sup.6 and R.sup.7 together form a C.sub.3-C.sub.7 ring, and R.sup.8 is C.sub.1-C.sub.6 alkyl, C.sub.7-C.sub.22 arylalkyl, SiR.sup.9R.sup.10R.sup.11, wherein R.sup.9, R.sup.10, and R.sup.11 are independently selected from C.sub.1-C.sub.4 alkyl or phenyl, or COR.sup.12, wherein R.sup.12 is H or C.sub.1-C.sub.21 alkyl; and wherein (i) the cross-linked charge-transporting polymer is a continuous infinite network, (ii) the charge-transporting polymer is capable of transporting an injected charge due to a system of overlapping orbitals along the charge-transporting polymer, and (iii) the injected charge is an electron injected or withdrawn either by an electrode arranged in contact with the charge-transporting polymer and/or through a reaction with a dopant capable of increasing the conductivity of the charge-transporting polymer.

2. A charge transporting semi-conducting material according to claim 1, further comprising an electrical dopant, wherein the electrical dopant is selected from a [3]-radialene compound, wherein each of the three carbon atoms connected to a cyclopropyl moiety of the [3]-radialene compound by a double bond is substituted independently with at least one of a nitrile group, C.sub.6-C.sub.14 perfluorinated aryl, or C.sub.2-C.sub.14 perfluorinated heteroaryl.

3. The charge transporting semi-conducting material according to claim 2, wherein one to three fluorine atoms in the perfluorinated substituents are replaced by groups independently selected from nitrile or trifluoromethyl.

4. The charge transporting semi-conducting material according to claim 1, wherein the groups from which R and R′ are selected comprise at least one substituent selected from alkyl, cycloalkyl, aryl, heteroaryl, or arylalkyl.

5. The charge transporting semi-conducting material according to claim 4, wherein when at least one of R and R′ comprises the substituent selected from alkyl, cycloalkyl, aryl, heteroaryl, or arylalkyl, the alkyl, cycloalkyl, aryl, heteroaryl, or arylalkyl is partially or fully substituted with halogen atoms.

6. A method for preparing the charge transporting semi-conducting material according to claim 1, the method comprising: i) providing a solution containing a) a first precursor charge transporting polymer comprising at least one covalently attached azide group; and/or a second precursor charge transporting polymer comprising at least one covalently attached acetylenic group, b) at least one solvent, ii) depositing the solution on a substrate, iii) removing the solvent, and iv) reacting the azide and acetylenic groups to effect crosslinking.

7. The method according to claim 6, wherein the first precursor charge transporting polymer further comprises at least one acetylenic group, and/or the second precursor charge transporting polymer comprises at least one azide group.

8. The method according to claim 6, wherein the solution further comprises at least one crosslinking agent comprising at least two functional groups selected from an azide and/or an acetylenic group.

9. A semiconducting device comprising a semi-conducting layer comprising a charge transporting semi-conducting material according to claim 1.

10. The device of claim 9, wherein the semiconducting layer is made by a printing process.

Description

(1) In the following, the invention will be described in further detail, by the way of examples.

(2) The figures show:

(3) FIG. 1: Scheme of network formation from azide group comprising crosslinkable moieties (A) and acetylenic groups comprising crosslinkable moieties (B);

(4) FIG. 2a: Scheme of the formation of a cross-linked charge transporting polymer without incorporating a dopant; lines mean charge-transporting precursor polymer, circles stand for small-molecule crosslinker, letters show the type of reactive groups in a crosslinkable moiety

(5) FIG. 2b: Scheme of the formation of a charge transporting semi-conducting material by incorporating a dopant into the crosslinked charge transporting polymer; lines mean charge-transporting precursor polymer, circles stand for small-molecule crosslinker, letters show the type of reactive groups in a crosslinkable moiety

(6) FIG. 3: Scheme of the crosslinking [2+3] cycloaddition;

(7) FIG. 4: Cut of ATR-IR spectra of a non-crosslinked layer according to step iv) of the inventive process before (full line) and after heating of a layer formed from PP1a and SC1 to 120° C. for 1 hour (dashed line). The decrease of the peak at 2.096 cm.sup.−1 shows high conversion of azide groups;

(8) FIG. 5a: Diagram illustrating the conductivity of the semiconducting material comprising crosslinked polymer PP1-SC1 doped with TCNQ-7 in dependence on heating duration at 120° C.;

(9) FIG. 5b: Diagram illustrating the conductivity of the semiconducting material comprising crosslinked polymer PP1-SC1 doped with Mo(tfd).sub.3 in dependence on heating duration at 120° C.;

(10) FIG. 5c: Diagram illustrating the conductivity of the semiconducting material comprising crosslinked polymer PP1-SC1 doped with PR-1 in dependence on heating duration at 120° C.;

(11) FIG. 5d: Diagram illustrating the conductivity of the semiconducting material comprising crosslinked polymer PP1-SC1 doped with PR-5 in dependence on heating duration at 120° C.;

(12) FIG. 5e: Diagram illustrating the conductivity of the semiconducting material comprising crosslinked polymer PP3-SC1 doped with PR-1 in dependence on heating duration at 120° C.;

(13) FIG. 6a: Diagram illustrating relative thickness of the semiconducting crosslinked layer made from PP1-SC1 doped with TCNQ-7 before and after rinsing with toluene. The bars show the experimental uncertainty of the values shown;

(14) FIG. 6b: Diagram illustrating relative thickness of the semiconducting crosslinked layer made from PP1-SC1 doped with Mo(tfd).sub.3 before and after rinsing with toluene;

(15) FIG. 6c: Diagram illustrating relative thickness of the semiconducting crosslinked layer made from PP1-SC1 doped with PR-1 before and after rinsing with toluene;

(16) FIG. 6d: Diagram illustrating relative thickness of the semiconducting crosslinked layer made from PP1-SC1 doped with PR-5 before and after rinsing with toluene;

(17) FIG. 6e Diagram illustrating relative thickness of the semiconducting crosslinked layer made from PP3-SC1 doped with PR-1 before and after rinsing with toluene;

(18) FIG. 7: Graph of luminance of the red OLED in dependence on the voltage;

(19) FIG. 8: Graph of efficiency of the red OLED in dependence on the current density.

(20) FIG. 9: Graph of luminance of the blue OLED in dependence on the voltage;

(21) FIG. 10: Graph of efficiency of the red OLED in dependence on the current density.

(22) FIG. 11: A photograph of a jet-printed pattern of Example J

EXAMPLES

(23) Several precursor charge transporting polymers and small molecule crosslinkers, listed in Tab. 1, were prepared and used for preparing the inventive charge transporting semiconducting material.

(24) TABLE-US-00001 TABLE 1 PP1a PP1b PP2a PP2b SC1 SC2 SC3 PP3 0 PP4 PP5 PP6 PP7 PP8 PP9 P1 P2 P3 PI2 0 PI3 PI4 PI5

(25) General Methods.

(26) Gel permeation chromatography (GPC) measurements of polymer molecular weights were carried out on Agilent 1100 Series (Agilent, USA) normal-temperature size exclusion chromatograph, equipped with a refractive index detector and one column PL Gel MIXED-B (Polymer Laboratories, U.K.); the eluent was tetrahydrofuran (THF), and the flow rate was 1 mL/min. Number-average molecular weights (M.sub.n) and polydispersity indexes (PDI) of the obtained polymers were determined based on calibration with polystyrene standards obtained from Polymer Standards Service (PSS, Germany).

Starting Materials for Polymer Preparation

2-{4-[bis(4-bromophenyl)amino]phenyl}butan-2-ol (1)

(27) ##STR00043##

(28) Tris(4-bromophenyl)amine (12.05 g, 25 mmol) was dissolved in 250 ml dry THF under argon and cooled down to −78° C. on acetone-dry ice bath. n-BuLi (2.5 M solution in hexane, 10 ml, 1 eq.) was added dropwise during 15 min. The mixture was stirred for next 15 min at −78° C. and quenched with excess of methylethylketone (5 ml).

(29) The solvent was evaporated at reduced pressure, a residue dissolved in ethyl acetate (100 ml), washed subsequently with 1% hydrochloric acid, saturated aqueous sodium bicarbonate and brine and dried over MgSO.sub.4. After evaporation of the solvent, crude product was obtained as viscous colorless liquid. Purification by column chromatography (SiO.sub.2, diethyl ether) afforded 9.2 g (1) as a white solid. (Yield ˜79% of theory, based on tris(4-bromo-phenyl)amine).

4-bromo-N-(4-bromophenyl)-N-[4-(butan-2-yl)phenyl]aniline (2)

(30) ##STR00044##

(31) (1) (8.77 g, 18.5 mmol) and NaBH.sub.4 (1.406 g, 37 mmol) were placed into a round-bottom flask, equipped with magnetic stirring bar, the flask was sealed by rubber septum and the atmosphere was replaced by argon. Dry diethyl ether (100 ml) was added by syringe, and the mixture was cooled to −78° C. on acetone-dry ice bath. Trifluoromethansulfonic acid (6 g, 40 mmol) was added at this temperature dropwise during 1 h. The mixture was allowed to warm up to the room temperature overnight. The solution was cooled on ice-bath and water (10 ml) was added in small portions. The acid was neutralized with 10% aqueous NaOH solution, and product extracted three times with diethyl ether. Combined ether fraction was washed with brine and dried over MgSO.sub.4. After the solvent removal at reduced pressure, crude product was obtained as very viscous liquid. Purification was done by column chromatography (SiO.sub.2, hexane-CH.sub.2Cl.sub.2 2:1). Yield 6.9 g (81%)

4-[bis(4-bromophenyl)amino]phenol (3)

(32) ##STR00045##
.fwdarw.

(33) Tris(4-bromophenyl)amine (12.05 g, 25 mmol) was dissolved in 250 ml dry THF under argon and cooled down to −78° C. on acetone-dry ice bath. n-BuLi (2.5 M solution in hexane, 10 ml, 1 eq.) was added dropwise at this temperature during 30 min. The mixture was stirred for next 15 min at −78° C. and triisopropylborate (8.6 ml, 1.5 eq.) was added at this temperature in one portion. The cooling bath was removed and the mixture was allowed to reach room temperature during ˜1 h. Solution was re-cooled to −10° C., acetic acid (1.9 ml, 1.3 eq.) was added and the mixture was stirred at room temperature for 30 minutes. Then, aqueous hydrogen peroxide (2.83 g of 30% solution diluted with 20 ml water) was added to the mixture, maintaining the temperature below 0° C. (salt-ice bath). After the peroxide addition was complete, the mixture was stirred overnight, quenched with an aqueous Na.sub.2S.sub.2O.sub.3 solution and extracted with diethyl ether. Organic layer was separated, washed with brine and dried over magnesium sulfate. Crude product, obtained after solvent evaporation, was purified by column chromatography (SiO.sub.2, eluent CH.sub.2Cl.sub.2). Yield 7.7 g (73%).

4-bromo-N-(4-(4-bromobutoxy)phenyl)-N-(4-bromophenyl)aniline (4)

(34) ##STR00046##

(35) Anhydrous THF (10 ml) was added to the mixture of (3) (0.418 g, 1 mmol), anhydrous potassium carbonate (1.5 eq., 0.207 g, 1.5 mmol) and catalytic amount (5 mol %) 18-crown-6. The mixture was heated to reflux for 1 h before 1,4-dibromobutane (5 eq, 5 mmol, 1.080 g) was added in one portion. Reaction mixture was heated at reflux overnight, poured into water and extracted with ether. The organic phase was washed with brine, dried over magnesium sulfate and filtered. Crude product, obtained after solvent evaporation, was purified by column chromatography (hexane:ethyl acetate 1:1) affording 0.51 g (95%) title compound as very viscous clear oil.

2-(4-(bis(4-bromophenyl)methyl)phenoxy)tetrahydro-2H-pyran (5)

(36) ##STR00047##

(37) To a (3) solution (2.1 g, 5 mmol) in dry dichloromethane, dihydropyran (1 mL, 11 mmol) and a catalytic amount of camphorsulfonic acid (14 mg, 0.06 mmol) were added at 0° C. The solution was stirred overnight at room temperature, poured into a saturated sodium hydrocarbonate solution, extracted with diethyl ether, washed with brine, dried over magnesium sulfate. The solvent was removed under reduced pressure and the residue purified by column chromatography (SiO.sub.2, hexane:diethylether 1:1). Yield 2.4 g (96% of theoretical).

3,6-dibromo-9-(2-ethylhexyl)-9H-carbazole (6)

(38) ##STR00048##

(39) A double-necked, flame-dried, 500 mL round-bottomed flask equipped with a magnetic stir bar and an argon inlet, was charged with potassium hydroxide (5.61 g, 100 mmol) and 3,6-dibromo-9H-carbazole (6.5 g 20 mmol), flushed with argon and sealed with a rubber septum. 100 mL anhydrous DMF were added under argon via cannula and the mixture was stirred for 30 minutes at room temperature. 1-bromo-2-ethylhexane (5.79 g, 30 mmol) was added dropwise by a syringe and the resulting mixture was stirred overnight at room temperature before it was poured into 300 mL of water, acidified to pH<7 by addition of concentrated HCl (35 wt. % aqueous solution) and extracted four times with CHCl.sub.3 (each portion 50 mL). The combined organic phase was washed with saturated aqueous NaHCO.sub.3 solution (lx), brine (5×), dried over MgSO.sub.4 and evaporated to dryness. The crude product was purified by column chromatography (SiO.sub.2, hexane-ethyl acetate 3:1 v/v).

(40) Yield: 8.3 g (95%)

3,6-dibromo-9-(4-bromobutyl)-9H-carbazole (7)

(41) ##STR00049##

(42) A double-necked, flame-dried, 500-mL round-bottomed flask equipped with a magnetic stir bar and an argon inlet, was charged with carbazole (11.37 g, 35 mmol) and potassium hydroxide (2.36 g, 42 mmol, 1.2 eq), flushed with argon sealed with a rubber septum. 200 mL anhydrous DMF were added under argon via cannula and the mixture was stirred for 30 minutes at room temperature. 16.5 g 1,4-dibromobutane (76.4 mmol-2.2 eq.) were added by a syringe in one portion, the resulting mixture was stirred at room temperature overnight, poured into ˜500 mL water and extracted with chloroform (4×150 mL). Combined organic layers were washed with water (2×), brine (2×), dried over magnesium sulfate and filtered. The solvent and other volatile residues were removed by vacuum distillation and the residue was purified by column chromatography on SiO.sub.2 with hexane:ethyl acetate (3:1 v/v) as an eluent.

(43) Yield: ˜8.8 g (54.4%)

2,7-dibromo-9,9-di(prop-2-yn-1-yl)-9H-fluorene (8)

(44) ##STR00050##

(45) A 100-mL, three-necked, round-bottomed flask was fitted with a stirring bar, dropping funnel, thermometer, and an argon inlet. The flask was charged with 2,7-dibromo-9H-fluorene (3.24 g, 10 mmol), 6 mL toluene, 50 mL DMSO, 5 mL 50 wt. % aqueous NaOH solution and 50 mg tetrabutyl ammonium chloride (TBAC), flushed with an inert gas and sealed. 6 g 3-bromoprop-1-yne (5 eq., 50 mmol) were added dropwise to the solution at the temperature below 20° C. (under cooling with a water-ice bath). The mixture was stirred under inert gas overnight at RT. The volatiles (toluene, propargyl bromide excess) were removed at a reduced pressure. The residue was diluted with water, the product was separated by filtration and washed with water (5×10 mL) and methanol (3×5 mL). The crude product was purified by crystallization from EtOH.

(46) Yield 2.7 g (63%)

((2,7-dibromo-9H-fluorene-9,9-diyl)bis(prop-1-yne-3,1-diyl))bis(triisopropylsilane) (9)

(47) ##STR00051##

(48) 2,7-dibromo-9,9-di(prop-2-yn-1-yl)-9H-fluorene (1.69 g, 4 mmol) was dissolved in 40 mL dry THF under argon and cooled down to −78° C. 6.4 mL lithium diisopropyl amide (LDA) 1.5 M solution in cyclohexane (9.6 mmol, 2.4 eq.) were added dropwise at this temperature during 15 min. The mixture was stirred for the 1 hour at −78° C. before chlorotriisopropylsilane (9.6 mmol, 1.85 g, 2.4 eq.) was added dropwise. The mixture was allowed to reach room temperature overnight, then re-cooled to 0° C. with ice-bath and quenched by addition of the saturated aqueous NH.sub.4Cl solution (1 mL). The mixture was transferred to a separatory funnel charged with 50 mL diethyl ether and 300 mL water. The organic phase was separated and the water phase was repeatedly extracted with diethyl ether (3×30 mL). The combined organic layers were washed with brine and dried over magnesium sulfate. The crude product, obtained after the solvent evaporation, was purified by column chromatography.

(49) Yield 2.27 g (80%)

Tri-tert-butylphosphinopalladium (II) dichloride (10)

(50) ##STR00052##

(51) The synthesis was performed in an argon box. A single-necked, flame-dried, 50 mL round-bottomed flask equipped with a magnetic stir-bar was charged with bis(acetonitrile)palladium(II) dichloride complex (0.52 g, 2 mmol), diethyl ether (25 ml) and tri-tert-butylphosphine (0.61 g, 3 mmol, 1.5 eq.). The mixture was stirred under argon at room temperature overnight. 25 ml hexane were added, the precipitated product was separated by filtration, washed with hexane and dried in vacuum at room temperature.

(52) Yield: 1.13 g (74%)

(53) Typical Co-Polymerization Procedures.

(54) 1. Kumada Catalyst-Transfer Polycondensation (KCTP)

(55) a) Preparation of Monomer Solution

(56) ##STR00053##

(57) Dibromo-monomer precursor (1 mmol) was placed into round-bottom flask equipped with magnetic stirring-bar, the flask was sealed and the air replaced by argon. 10 mL dry THF were added via syringe and the solution was cooled to −78° C. using a dry ice-acetone bath. n-BuLi solution (1 eq.) was added at this temperature during 15 min and the mixture was stirred for 15 minutes. An addition of MgBr.sub.2 (1.1 mmol, 0.202 g) solution in THF followed. The reaction was allowed to reach RT over 30 min.

(58) b) Polymerisation Procedure

(59) ##STR00054##

(60) Monomer solutions, prepared separately from different dibromo-monomer precursors, were mixed together in the desired proportion under argon and then catalyst suspension (typically 0.01 eq. of [1,3-Bis(diphenylphosphino)propane]dichloronickel(II) in THF) was added via septum by syringe. Polymerisation was allowed to proceed overnight at room temperature and terminated by addition of the methanol. Crude polymer was obtained by precipitation in excess of the methanol. Purification of the polymer was done by triple re-precipitation in methanol from a toluene solution.

(61) 2. Negishi Catalyst-Transfer Polycondensation (NCTP)

(62) a) Preparation of Monomer Solution

(63) ##STR00055##

(64) Dibromo-monomer precursor (1 mmol) was placed into round-bottom flask equipped with magnetic stirring-bar, the flask was sealed and the air replaced by argon. Dry THF (10 ml) was added by syringe and the solution was cooled to −78° C. using dry ice-acetone bath. n-BuLi solution (1 eq.) was added at this temperature during 15 min, the mixture was stirred for 15 minute. An addition of ZnCl.sub.2 (1.1 mmol, 1.1 eq) solution in THF followed. Reaction was allowed to reach room temperature over 30 min.

(65) b) Polymerization Procedure

(66) ##STR00056##

(67) Monomer solutions, prepared separately from different dibromo-monomer precursors, were mixed together in the desired proportion under argon and then catalyst suspension (typically 0.01 eq. tri-tert-butylphosphinopalladium(II) dichloride (10) in THF) was added via septum by syringe. Polymerisation was allowed to proceed 15 minutes at room temperature and terminated by addition of the methanol. Crude polymer was obtained by precipitation in excess of the methanol. Purification of the polymer from Pd-residues was done in a followed way. The crude material was dissolved in 40 mL toluene and treated with 5 mL of 1% (wt.) aqueous sodium diethyldithiocarbamate solution overnight. The organic layer was separated, washed with brine, dried over MgSO4 and evaporated to a half of its initial volume. The crude polymer was obtained by precipitation of this solution with tenfold excess methanol as a pale yellow solid.

(68) Example Co-Polymerization Procedure.

(69) a) Preparation of Monomer Solutions

(70) ##STR00057##

(71) Dibromo-monomer precursor (4) (1 mmol, 0.544 g) was placed into round-bottom flask equipped with magnetic stirring-bar, the flask was sealed and the air replaced by argon. Dry THF (10 ml) was added by syringe and the solution was cooled to −78° C. using dry ice-acetone bath. n-BuLi solution in hexane (1 eq.) was added at this temperature during 15 min, the mixture was stirred for 15 minutes. An addition of MgBr.sub.2 (1.1 mmol, 0.202 g) solution in 5 mL THF followed. The reaction mixture was allowed to reach room temperature over 30 min.

(72) 2,7-dibromo-9,9-bis(2-ethylhexyl)-9H-fluorene (1 mmol, 0.548 g) was placed into round-bottom flask equipped with magnetic stirring-bar, the flask was sealed and the air replaced by argon. Dry THF (10 ml) was added by syringe and the solution was cooled to −78° C. using dry ice-acetone bath. n-BuLi solution (1 eq.) was added at this temperature during 15 min, the mixture was stirred for 15 minute. An addition of MgBr.sub.2 (1.1 mmol, 0.202 g) solution in THF followed. The reaction mixture was allowed to reach room temperature over 30 min.

(73) b) Polymerization (Polymeric Intermediate PI1)

(74) ##STR00058##

(75) Prepared solutions were mixed together under argon and then catalyst suspension (typically 0.01 eq. of [1,3-Bis(diphenylphosphino)propane]dichloronickel(II) in THF) was added via septum by syringe. Polymerisation was allowed to proceed overnight at room temperature and terminated by addition of methanol. Crude polymer was obtained by precipitation in excess of methanol. Purification of the polymer was done by triple re-precipitation in methanol from a toluene solution.

(76) Model Polymers

Poly[(9,9-di(2-ethylhex-1-yl)-9H-fluoren-2,7-diyl)-co-(4-4′-4″-(4-(butan-2-yl))-N,N-diphenylaniline)] (P2)

(77) ##STR00059##

(78) The polymer was prepared according to the previous general procedure for NCTP from 2.34 g (4.36 mmol) of dibromo-9,9-bis(2-ethylhexyl)-9H-fluorene and 2 g (4.36 mmol) 4-bromo-N-(4-bromophenyl)-N-[4-(butan-2-yl)phenyl]aniline.

(79) Yield 2.71 g (90%) as a pale yellow solid.

(80) M.sub.n=18 800 PDI=3.45

Poly(9-(2-ethylhexyl)-9H-carbazole-3,6-diyl) (P3)

(81) ##STR00060##

(82) The polymer was prepared according to the previous general procedure for NCTP from 6.23 g (14.25 mmol) 3,6-dibromo-9-(2-ethylhexyl)-9H-carbazole.

(83) Yield 3.6 g (80.8%) as a white solid.

(84) M.sub.n=6000; PDI=1.77

(85) Functional Polymers

Poly[(9,9-di(2-ethylhex-1-yl)-9H-fluoren-2,7-diyl)-co-(4-4′-4″-(4-azidobutyl)-N,N-diphenylaniline)] (azide-containing polymer PP3)

(86) ##STR00061##

(87) 200 mg 4-bromobutyl-group bearing units containing polymer PI1, prepared according to the previous general KCTP procedure from 0.145 g 2,7-dibromo-9,9-bis(2-ethylhexyl)-9H-fluorene and 0.150 g 4-bromo-N-(4-bromophenyl)-N-(4-(4-bromobutoxy)phenyl)aniline (4) with [1,3-bis(diphenylphosphino)propane]dichloro-nickel(II) catalyst, were dissolved in 10 ml THF. Lithium azide (5 eq. based on alkyl-bromide groups in polymer, typically 25 mg) dissolved in 2 ml anhydrous DMF was added in one portion at room temperature. The solution was stirred at room temperature for 2 days, solids were filtered off and the filtrate poured into tenfold excess methanol. The precipitated crude polymer was separated by filtration and purified by re-precipitation from a toluene solution into methanol. The yield was almost quantitative.

(88) M.sub.n=15 239, PDI=2.09.

Poly[(9,9-di(2-ethylhex-1-yl)-9H-fluoren-2,7-diyl)-co-(4-4′-N,N-diphenyl-4″-hydroxyaniline)] (Hydroxy-Groups Containing Polymeric Intermediate PI3)

(89) ##STR00062## ##STR00063##

(90) 400 mg polymeric intermediate PI2, prepared according to the previous general KCTP procedure from 0.145 g 2,7-dibromo-9,9-bis(2-ethylhexyl)-9H-fluorene and from 0.145 g of 2-(4-(bis(4-bromophenyl)methyl)phenoxy)tetrahydro-2H-pyran, were dissolved in 40 ml dry THF. 3 mL dry methanol and 20 mg p-toluenesulfonic acid as a solution in 2 ml dry MeOH were added at room temperature. The reaction mixture was stirred at room temperature for 3 days and poured into methanol. The precipitated crude polymer was separated by filtration and purified by re-precipitation with methanol from a toluene solution.

(91) M.sub.n=14 059, PDI=1.77

Poly[(9,9-di(2-ethylhex-1-yl)-9H-fluoren-2,7-diyl)-co-(4-4′-4″-(prop-2-yn-1-yloxy)-N,N-diphenylaniline)] (alkyne-containing polymer PP4)

(92) ##STR00064##

(93) 200 mg hydroxyl-groups containing polymeric intermediate PI3, obtained as described above, was dissolved in 10 ml anhydrous THF. Anhydrous potassium carbonate (70 mg, ˜5 eq.) and a catalytic amount of 18-crown-6 were added and the mixture was heated to reflux for 1 h before propargyl bromide (149 mg, ˜5 eq.) was added in one portion. The reaction mixture was heated at reflux overnight, then poured into water and extracted with toluene. The organic phase was washed with brine, dried over magnesium sulfate and filtered. The solution was concentrated and poured into tenfold excess of methanol. The precipitated crude polymer was separated by filtration and purified by re-precipitation with methanol from a toluene solution.

Poly(9-(2-ethylhexyl)-9H-carbazol-3,6-diyl-co-(9-(4-bromobutyl)-9H-carbazole-3,6-diyl)) (4-bromobutyl-groups containing polymeric intermediate PI4)

(94) ##STR00065## ##STR00066##

(95) The polymer was prepared according to the previous general procedure for NCTP from 1.38 g (3 mmol) 3,6-dibromo-9-(4-bromobutyl)-9H-carbazole (7) and 1.31 g (3 mmol) 3,6-dibromo-9-(2-ethylhexyl)-9H-carbazole.

(96) Yield 1.23 g (71%)

(97) M.sub.n=3000; PDI=1.43

Poly(9-(2-ethylhexyl)-9H-carbazole-3,6-diyl)-co-(9-(4-azidobutyl)-9H-carbazole-3,6-diyl)) (PP5)

(98) ##STR00067##

(99) 288.5 mg poly(N-(2-ethylhexyl)carbazol-3,6-diyl-co-(N-(4-bromobutyl)carbazol-3,6-diyl)) (PI4) were dissolved in 10 mL THF. 13 mg lithium azide (5 eq. based on alkyl-bromide groups in polymer) dissolved in 2 ml anhydrous DMF were added in one portion at room temperature. The solution was stirred at room temperature for 2 days, solids were filtered off and the filtrate poured into tenfold excess methanol. The precipitated polymer was separated by filtration and purified by re-precipitation from a toluene solution into methanol.

(100) Yield 210 mg (78%)

(101) M.sub.n=3400; PDI=1.43

Poly(9-(2-ethylhexyl)-9H-carbazole-3,6-diyl)-co-(9-(prop-2-yn-1-yl)-9H-carbazole-3,6-diyl) (PP6)

1. (6-bromo-9-(trimethylsilyl)-9H-carbazol-3-yl)zinc(II) Chloride Solution

(102) ##STR00068##

(103) 3,6-dibromo-9H-carbazole (0.975 g, 3 mmol) was placed into round-bottom flask equipped with magnetic stirring bar, the flask was sealed and the air replaced with argon. Dry THF (30 ml) was added by syringe followed by dropwise addition of ethylmagnesium bromide solution in diethyl ether (1 ml, 3 mmol). The mixture was stirred at room temperature until gas evolution ceased (approximately 20 minutes). 0.38 mL (3 mmol, 1 eq.) chlorotrimethylsilane was added dropwise and the resulting solution was stirred for an additional hour at room temperature and cooled down to −78° C. using dry ice-acetone bath. n-BuLi solution (1.2 ml, 2.5M in n-hexane, 3 mmol) was added at this temperature during 15 min, the mixture was stirred for 15 minute. An addition of ZnCl.sub.2 (1.1 mmol, 0.202 g) solution in THF followed. The reaction was allowed to reach room temperature over 30 min.

2. Poly(9-(2-ethylhexyl)-9H-carbazole-3,6-diyl)-co-(9-(trimethoxysilyl)-9H-carbazole-3,6-diyl) (PI5)

(104) ##STR00069##

(105) The solution of (6-bromo-9-(trimethylsilyl)-9H-carbazol-3-yl)zinc(II) chloride, prepared as described above, was mixed under argon with a monomer solution prepared according to the general procedure for NCTP polymerization from 1.31 g (3 mmol) 3,6-dibromo-9-(2-ethylhexyl)-9H-carbazole. Then, catalyst suspension (0.005 eq. PdCl.sub.2P(tBu).sub.3 in THF) was added via septum by a syringe. The polymerization was allowed to proceed for 15 minutes at room temperature and terminated by methanol addition. The crude polymer was purified according to the procedure described above.

(106) Yield 0.93 g (60%)

3. Poly(9-(2-ethylhexyl)-9H-carbazole-3,6-diyl)-co-(9-(prop-2-yn-1-yl)-9H-carbazole-3,6-diyl) (PP6)

(107) ##STR00070##

(108) 928 mg poly(9-hexyl-9H-carbazole-3,6-diyl)-co-(9-(trimethoxysilyl)-9H-carbazole-3,6-diyl) (PI5, ˜3 mmol NH-groups based on 1H-NMR assay) were dissolved in 50 mL dry THF under argon atmosphere. 3 ml 80 wt. % propargyl bromide solution in toluene were added in one portion at room temperature. Then, tetrabutyl ammonium hydroxide (TBAH, 1.94 g, ˜3 mmol) in methanolic solution was added with such a rate, that the next droplet of the solution is added after consumption of the previous one (as judged by bleaching of orange-red color of the solution appearing immediately after each base addition). The hydroxide addition was completed after ˜4 hours, the mixture was stirred for an additional hour, filtered through a 200 nm syringe membrane filter, concentrated to about 15 mL and poured into a tenfold excess methanol. The polymer was obtained as a white solid after filtration and drying in vacuum at room temperature.

Poly((9-(2-ethylhexyl)-9H-carbazole-3,6-diyl)-co-(9,9-bis(3-(triisopropylsilyl)-prop-2-yn-1-yl)-9H-fluorene-2,7-diyl) (PP7)

(109) ##STR00071## ##STR00072##

(110) The polymer was prepared according to the previous general procedure for NCTP from 274 mg (0.63 mmol) 3,6-dibromo-9-(2-ethylhexyl)-9H-carbazole and 446 mg (0.63 mmol) ((2,7-dibromo-9H-fluorene-9,9-diyl)bis(prop-1-yne-3,1-diyl))bis(triiso-propylsilane) (9).

(111) Yield 440 mg (84%) as a pale yellow solid.

Poly((9-(2-ethylhexyl)-9H-carbazole-3,6-diyl)-co-(9,9-bis(prop-2-yn-1-yl)-9H-fluorene-2,7-diyl) (PP8)

(112) ##STR00073##

(113) A 25-mL, single-necked, round-bottomed flask, fitted with a stirring bar, was charged with poly((9-(2-ethylhexyl)-9H-carbazole-3,6-diyl)-co-(9,9-bis(3-(triisopropylsilyl)-prop-2-yn-1-yl)-9H-fluorene-2,7-diyl) (440 mg) and sealed with a rubber septum. 10 mL anhydrous THF were added through the septum via syringe and the mixture was stirred at a room temperature until a homogeneous solution was obtained. 1.2 ml 1M tetrabutylammonium fluoride (TBAF, solution in THF) were added to the polymer solution via syringe and the resulting mixture was stirred at RT overnight.

(114) The polymer was obtained by precipitation of the solution into a tenfold excess methanol, filtration and drying in vacuum at room temperature.

(115) Yield 250 mg (76%)

(116) M.sub.n=6000, PDI=8.05

(117) Conductivity and Stability of a Doped Crosslinked Layer

(118) An anisole solution containing 1.74% polymeric precursor PP3, 0.09% p-dopant PR-1 and 0.17% small-molecule crosslinker SC1 was prepared and spin-coated on ITO substrate for 30 s at 1000 rpm. The conductivity and thickness of the film after baking on hot plate in nitrogen atmosphere for 0, 3, 15 and 30 min were measured.

(119) The formed films were spin-rinsed with toluene after 10 s soaking-time before spinning After 30 min drying at 80° C., the thickness and conductivity were measured again.

(120) Red OLED

(121) On 90 nm thick indium tin oxide (ITO) layer fabricated on a glass substrate, 50 nm thick crosslinked hole-transporting layer from PP3 and SC1 doped with PR1 was cast by spin-coating from 2 wt. % toluene solution (weight ratio of components as above). After drying and baking in an inert atmosphere at 120° C. for 30 minutes, a doped crosslinked layer having thickness 50 nm was obtained. Following layers were prepared on top of the crosslinked layer by vacuum deposition: 10 nm undoped electron blocking layer composed from N4, N4, N4″, N4″-tetra([1,1′-biphenyl]-4-yl)-[1,1′:4,4′-terphenyl]-4,4″-diamine, 40 nm emitting layer composed from 3,9-di(naphtalen-2-yl)perylene and 3,10-di(naphtalen-2-yl)perylene mixture (DNP), aluminium quinolate (Alq.sub.3) and 4-dicyanomethylene-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyrane (DCJTB) in weight ration 70:29:1, 10 nm hole blocking layer from 4-(naphtalen-1-yl)-2,7,9-triphenylpyrido[3,2-h]quinazoline, 10 nm electron transporting layer from 4-(naphtalen-1-yl)-2,7,9-triphenylpyrido[3,2-h]quinazoline and tetrakis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinato)ditungsten (II) (W(hpp).sub.4) in the weight ratio 9:1, and 100 nm thick Al cathode. The OLED had maximum intensity at 630 nm, quantum efficiency 7.2%, current efficiency 10.9 cd/A and power efficiency 13.6 lm/W at 10 mA/cm.sup.2 (see also FIGS. 7 and 8).

(122) Blue OLED

(123) On 90 nm thick indium tin oxide (ITO) layer fabricated on a glass substrate, 50 nm thick crosslinked hole-transporting layer from PP5 and PP9 (poly(9-butyl-9H-carbazole-3,6-diyl)-co-(9-(prop-2-yn-1-yl)-9H-carbazole-3,6-diyl, ratio of butyl and propargyl units 19:1, prepared analogously to PP6) doped with 20 wt. % PR1 based on the overall polymer weight was cast by spin-coating from 2 wt. % toluene-anisole solution. After drying and baking in an inert atmosphere at 120° C. for 120 minutes, a doped crosslinked layer having thickness 40 nm was obtained. Following layers were prepared on top of the crosslinked layer by vacuum deposition: 90 nm undoped electron blocking layer composed from N4,N4″-di(naphtalen-1-yl)-N4,N4″-diphenyl-[1,1′:4,4′-terphenyl]-4,4″-diamine, 20 nm blue fluorescent emitting layer composed of ABH113 (obtained from Sun Fine Chem (SFC), Korea) doped with NUBD370 (also from SFC, host:emitter ratio 95:5 by weight), 30 nm electron transporting layer composed of 2-(4-(9,10-di(naphtalen-2-yl)anthracen-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole (CAS 561064-11-7) and lithium 8-hydroxyquinolinolate (CAS 850918-68-2) in weight ratio 1:1 and 100 nm thick Al cathode. The OLED had voltage 5.0 V, quantum efficiency 5.9%, current efficiency 5.5 cd/A and power efficiency 3.4 lm/W at 15 mA/cm.sup.2 (see also FIGS. 9 and 10). The lifetime of the OLED, expressed as LT97 (the time necessary for luminance decrease to 97% of its initial value), was 53 hours.

Example J

Jet Printing

(124) A jet-printed pattern was created using as ink the anisole solution PP3 and SC1 with PR1 in the same ratio as above and jet printer PiXDRO LP50. FIG. 9 shows a blue “hybrid” OLEDs with ink jet printed crosslinked p-HTL, a) OLED test layout, b) pixel, ink jet printing not optimized, c) pixel at optimum ink jet printing with 1% concentration of the polymer by weight, resolution 300 dpi and 400 mm/s printing speed.

(125) Results

(126) FIG. 5a-5e show the conductivities of layers comprising PP1a and SC1 resp. PP3 and SC1 and different dopants during heating to 120° C. for 3 to 20 minutes. It is shown that the conductivity of crosslinked layers remains in the range sufficient for practical applicability and mostly is practically independent on crosslinking

(127) FIG. 6a-6e show thickness of the crosslinked layers doped with different dopants before and after rinsing with toluene. The measured thickness of the layers remains constant within the range of experimental errors. The resistance of the layers against toluene, which is a good solvent for non-crosslinked materials, shows successful crosslinking of the prepared layers.

(128) The conductivity of 10.sup.−6-10.sup.−5 S/cm, as required for a hole transporting layer, was maintained in the doped layer after crosslinking. If the dopant was destroyed during the cycloaddition reaction, a significant lower conductivity of about 10.sup.−10 S/cm would be obtained.

(129) Accordingly, there is clear evidence that the inventive charge transporting semi-conducting material as well as the inventive process provide the possibility to build crosslinked charge transporting layers from solution under mild conditions.

(130) Further evidence to successful crosslinking is given by the ATR-IR spectra shown in FIG. 4.

(131) Spectrum 1 (full line), corresponding to the polymer before crosslinking, features a pronounced absorption band at 2.096 cm.sup.−1 which is characteristic to the azide group N.sub.3.

(132) Spectrum 2 (dashed line), corresponding to the polymer after cross-linking, features a significant decrease of this band.

(133) The red and blue OLEDs demonstrate that a crosslinked charge transporting layer comprising semiconducting material according to the invention can be successfully used in organic electronic devices.

(134) The jet-printing example J shows that the invention enables preparation of organic electronic devices like OLEDs by printing techniques.

(135) The features disclosed in the foregoing description and in the claims may, both separately and in any combination thereof, be material for realizing the invention in diverse forms thereof.