Electronic semiconducting device and method for preparing the electronic semiconducting device

Abstract

The present invention relates to an electronic device comprising between a first electrode and a second electrode at least one first hole transport layer, wherein the first hole transport layer comprises (i) at least one first hole transport matrix compound consisting of covalently bound atoms and (ii) at least one electrical p-dopant selected from metal sate and from electrically neutral metal complexes comprising a metal cation and a at least one anion and/or at least one anionic ligand consisting of at least 4 covalently bound atoms, wherein the metal cation of the electrical p-dopant is selected from alkali metals; alkaline earth metals, Pb, Me, Fe, Co, Ni, Zn, Cd; rare earth metals in oxidation state (II) or (III); Al, Ga, In; and from Sn, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W in oxidation state (TV) or less; provided that a) p-dopants comprising anion or anionic ligand having generic formula (Ia) or (Ib) wherein A.sup.1, A.sup.2, A.sup.3 and A.sup.4 are independently selected from CO, SO.sub.2 or POR.sup.1; R.sup.1=electron withdrawing group selected from the group comprising halide, nitrile, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, or halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms; B.sup.1, B.sup.2, B.sup.3 and B.sup.4 are same or independently selected from substituted or unsubstituted C.sub.1 to C.sub.20 alkyl, substituted or unsubstituted C.sub.1 to C.sub.20 heteroalkyl, substituted or unsubstituted C.sub.6 to C.sub.20 aryl, substituted or unsubstituted C.sub.5 to C.sub.20 heteroaryl, or B.sup.1 and B.sup.2 form a ring; and b) p-dopants consisting of Li cation and an anion selected from perchlorate and tetrafluoroborate are excluded, and the first hole transport layer comprises a sublayer, wherein the electrical dopant is comprised in an amount, by weight and/or by volume, exceeding the total amount of other components which may additionally be comprised in the sublayer, and a method for preparing the same. ##STR00001##

Claims

1. Electronic device comprising, between a first electrode and a second electrode, at least one first hole transport layer, wherein the first hole transport layer comprises (i) at least one first hole transport matrix compound consisting of covalently bound atoms and (ii) at least one electrical p-dopant selected from metal salts and from electrically neutral metal complexes comprising a metal cation and a at least one anion and/or at least one anionic ligand consisting of at least 4 covalently bound atoms, wherein the metal cation of the electrical p-dopant is selected from alkali metals; alkaline earth metals, Pb, Mn, Fe, Co, Ni, Zn, Cd; rare earth metals in oxidation state (II) or (III); Al, Ga, In; and from Sn, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W in oxidation state (IV) or less; provided that a) the at least one electrical p-dopant comprises an anion or anionic ligand having generic formula (Ia) or (Ib) ##STR00023## wherein A.sup.1, A.sup.2, A.sup.3 and A.sup.4 are independently selected from CO, SO.sub.2 or POR.sup.1; R.sup.1=electron withdrawing group selected from the group comprising halide, nitrile, halogenated or perhalogenated C.sub.1 to C.sub.20 alkyl, halogenated or perhalogenated C.sub.6 to C.sub.20 aryl, or halogenated or perhalogenated heteroaryl with 5 to 20 ring-forming atoms; B.sup.1, B.sup.2, B.sup.3 and B.sup.4 are same or independently selected from substituted or unsubstituted C.sub.1 to C.sub.20 alkyl, substituted or unsubstituted C.sub.1 to C.sub.20 heteroalkyl, substituted or unsubstituted C.sub.6 to C.sub.20 aryl, substituted or unsubstituted C.sub.5 to C.sub.20 heteroaryl, or B.sup.1 and B.sup.2 form a ring; and b) p-dopants consisting of Li cation and an anion selected from perchlorate and tetrafluoroborate are excluded from the at least one electrical p-dopant, and the first hole transport layer comprises a sub-layer, wherein the at least one electrical dopant is comprised in an amount, by weight and/or by volume, exceeding the total amount of other components which may additionally be comprised in the sub-layer.

2. Electronic device according to claim 1, wherein the sub-layer comprises the at least one electrical p-dopant in an amount of at least 60 wt % with respect to the total weight of the sub-layer.

3. Electronic device according to claim 1, wherein the anion and/or anionic ligand consists of at least 5 covalently bound atoms.

4. Electronic device according to claim 1, wherein the anion and/or anionic ligand comprises at least one atom selected from B, C, N.

5. Electronic device according to claim 1, wherein the anion and/or anionic ligand comprises at least two atoms selected from B, C and N which are bound to each other by a covalent bond.

6. Electronic device according to claim 1, wherein the anion and/or anionic ligand comprises at least one peripheral atom selected from H, N, O, F, Cl, Br and I.

7. Electronic device according to claim 1, wherein the anion and/or anionic ligand comprises at least one electron withdrawing group selected from halogenated alkyl, halogenated (hetero)aryl, halogenated (hetero)arylalkyl, halogenated alkylsulfonyl, halogenated (hetero)arylsulfonyl, halogenated (hetero)arylalkylsulfonyl, cyano.

8. Electronic device according to claim 7, wherein the electron withdrawing group is a perhalogenated group.

9. Electronic device according to claim 8, wherein the perhalogenated electron withdrawing group is a perfluorinated group.

10. Electronic device according to claim 1, wherein the metal cation of the at least one electrical p-dopant is selected from Li(I), Na(I), K(I), Rb(I), Cs(I); Mg(II), Ca(II), Sr(II), Ba(II), Sn(II), Pb(II), Mn(II), Fe(II), Co(II), Ni(II), Zn(II), Cd(II), Al(III); rare earth metal in oxidation state (III), V(III), Nb(III), Ta(III), Cr(III), Mo(III), W(III) Ga(III), In(III) and from Ti(IV), Zr(IV), Hf(IV) Sn(IV).

11. Electronic device according to claim 1, wherein in the p-dopant molecule, the atom of the anion and/or of the anionic ligand which is closest to the metal cation is a C or a N atom.

12. Electronic device according to claim 1, wherein the acidity of the electrically neutral conjugated acid formed from the anion and/or anionic ligand by addition of one or more protons in 1,2-dichloroethane is higher than that of HCl.

13. Electronic device according to claim 1, wherein the electrical p-dopant has energy level of its lowest unoccupied molecular orbital computed by standard quantum chemical method and expressed in absolute vacuum scale at least 0.5 eV above the energy level of the highest occupied orbital of the covalent hole transport compound computed by the standard quantum chemical method, wherein the standard quantum chemical method uses the software package TURBOMOLE using DFT functional B3LYP with the basis set def2-TZVP.

14. Electronic device according to claim 1, wherein the first hole transport matrix compound is an organic compound.

15. Electronic device according to claim 1, which is an organic electroluminescent device, an organic transistor, or an organic photovoltaic device.

16. Electronic device according to claim 1, wherein all layers between the first and second electrode as well as the electrode deposited on top of the last organic layer are preparable by vacuum deposition at a pressure below 1×10.sup.−3 Pa.

17. Method for preparation of the electronic device of claim 1, the method comprising at least one step wherein the covalent hole transport matrix compound and the at least one electrical p-dopant are in mutual contact exposed to a temperature above 50° C.

18. Method according to claim 17, further comprising a step, wherein the at least one electrical p-dopant is evaporated at a reduced pressure.

19. Electronic device according to claim 1, wherein the sub-layer comprises the at least one electrical p-dopant in an amount of at least 75 wt %.

20. Electronic device according to claim 1, wherein the sub-layer comprises the at least one electrical p-dopant in an amount of at least 98 wt %.

Description

DESCRIPTION OF DRAWINGS

(1) In the following, further embodiments will be described in further detail, by way of example, with reference to figures. In the figures show:

(2) FIG. 1 a schematic representation of an active OLED display, the display having a plurality of OLED pixels,

(3) FIG. 2 is a schematic sectional view of an organic light-emitting diode (OLED), according to an exemplary embodiment of the present invention;

(4) FIG. 3 is a schematic sectional view of an OLED, according to an exemplary embodiment of the present invention.

(5) FIG. 4 is a schematic sectional view of a tandem OLED comprising a charge generation layer, according to an exemplary embodiment of the present invention.

(6) FIG. 5 shows the crystal structure of the inverse coordination complex E3, having the summary formula C.sub.42F.sub.48N.sub.5O.sub.13S.sub.6Zn.sub.4.

DESCRIPTION OF EMBODIMENTS

(7) FIG. 1 shows a schematic representation of an active OLED display 1 having a plurality of OLED pixels 2, 3, 4 provided in an OLED display 1.

(8) In the OLED display 1, each pixel 2, 3, 4 is provided with an anode 2a, 3a, 4a being connected to a driving circuit (not shown). Various equipment able to serve as a driving circuit for an active matrix display is known in the art. In one embodiment, the anodes 2a, 3a, 4a are made of a TCO, for example of ITO.

(9) A cathode 6 is provided on top of an organic stack comprising an electrically doped hole transport layer (HTL) 7, an electron blocking layer (EBL) 5, a light emitting layer (EML) having sub-regions 2b, 3b, 4b assigned to the pixels 2, 3, 4 and being provided separately in an electron transport layer (ETL) 9. For example, the sub-regions 2b, 3b, 4b can provide an RGB combination for a color display (R—red, G—green, B—blue). In another embodiment, pixels for individual colours may comprise analogous white OLEDs provided with appropriate combination of colour filters. By applying individual drive currents to the pixels 2, 3, 4 via the anodes 2a, 3a, 4a and the cathode 6, the display pixels 2, 3, 4 are operated independently.

(10) FIG. 2 is a schematic sectional view of an organic light-emitting diode (OLED) 100, according to an exemplary embodiment of the present invention. The OLED 100 includes a substrate 110, an anode 120, a hole injection layer (HIL) 130, a hole transport layer (HTL) 140, an emission layer (EML) 150, an electron transport layer (ETL) 160. The electron transport layer (ETL) 160 is formed directly on the EML 150. Onto the electron transport layer (ETL) 160, an electron injection layer (EIL) 180 is disposed. The cathode 190 is disposed directly onto the electron injection layer (EIL) 180.

(11) Instead of a single electron transport layer 160, optionally an electron transport layer stack (ETL) can be used.

(12) FIG. 3 is a schematic sectional view of an OLED 100, according to another exemplary embodiment of the present invention. 3 differs from FIG. 2 in that the OLED 100 of FIG. 3 comprises an electron blocking layer (EBL) 145 and a hole blocking layer (HBL) 155.

(13) Referring to FIG. 3, the OLED 100 includes a substrate 110, an anode 120, a hole injection layer (HIL) 130, a hole transport layer (HTL) 140, an electron blocking layer (EBL) 145, an emission layer (EML) 150, a hole blocking layer (HBL) 155, an electron transport layer (ETL) 160, an electron injection layer (EIL) 180 and a cathode electrode 190.

(14) FIG. 4 is a schematic sectional view of a tandem OLED 200, according to another exemplary embodiment of the present invention. FIG. 4 differs from FIG. 3 in that the OLED 100 of FIG. 3 further comprises a charge generation layer and a second emission layer.

(15) Referring to FIG. 4, the OLED 200 includes a substrate no, an anode 120, a first hole injection layer (HIL) 130, a first hole transport layer (HTL) 140, a first electron blocking layer (EBL) 145, a first emission layer (EML) 150, a first hole blocking layer (HBL) 155, a first electron transport layer (ETL) 16o, an n-type charge generation layer (n-type CGL) 185, a hole generating layer (p-type charge generation layer; p-type GCL) 135, a second hole transport layer (HTL) 141, a second electron blocking layer (EBL) 146, a second emission layer (EML) 151, a second hole blocking layer (EBL) 156, a second electron transport layer (ETL) 161, a second electron injection layer (EIL) 181 and a cathode 190.

(16) While not shown in FIG. 2, FIG. 3 and FIG. 4, a sealing layer may further be formed on the cathode electrodes 190, in order to seal the OLEDs 100 and 200. In addition, various other modifications may be applied thereto.

SYNTHESES EXAMPLES

lithium tris(4,5,6,7-tetrafluoro)-3-(trifluoromethyl-1H-indazol-1-yl)hydroborate

Step 1: 4,5,6,7-tetrafluoro-3-(trifluoromethyl)-1H-indazole

(17) ##STR00006##

(18) 11.09 g (45.1 mmol) perfluoroacetophenone are dissolved in 100 mL toluene. The solution is cooled with an ice bath and 2.3 mL (2.37 g, 47.3 mmol, 1.05 eq) hydrazine-monohydrate is added dropwise. The mixture is heated to reflux for 3 days. After cooling to room temperature, the mixture is washed two times with 100 mL saturated aqueous sodium hydrogen carbonate solution and two times with 100 mL water, dried over magnesium sulfate and the solvent is removed under reduced pressure. The yellow, oily residue is distilled from bulb to bulb at a temperature about 140° C. and pressure about 12 Pa. The crude product is dissolved in hot hexane and the solution stored at −18° C. The precipitated solid is filtered off and the slurry washed two times in 10 mL hexane. 5.0 g (43%) product is obtained as a slightly yellow solid.

(19) GCMS: confirms the expected M/z (mass/charge) ratio 258

Step 2: lithium tris(4,5,6,7-tetrafluoro-3-(trifluoromethyl)-1H-indazol-1-yl)hydroborate

(20) ##STR00007##

(21) 5.1 g (19.8 mmol) 4,5,6,7-tetrafluoro-3-(trifluoromethyl)-1H-indazole is added under Ar counter-flow to an out-baked Schlenk flask and treated with 3 mL toluene. Freshly pulverized lithium borohydride is added to the starting material. The mixture is heated to 101° C., until hydrogen formation ceases (ca. 4 h). After slight cooling, 15 mL hexane are added, the mixture is heated to reflux for to min and cooled to room temperature. The precipitated solid is filtered off, washed with 10 mL hot hexane and dried in high vacuum. 2.55 g (49%) product are obtained as an off-white solid.

lithium tris(3,5-bis(trifluoromethyl)-1H-pyrazol-1-yl)hydroborate (PB-2)

(22) ##STR00008##

(23) 2.0 g (9.8 mmol, 5 eq) 3,5-bis(trifluoromethyl)pyrazole in a baked-out Schlenk flask is dissolved in 5 mL dry toluene. 43 mg (1.96 mmol, 1 eq) freshly pulverized lithium borohydride is added under Ar counter-flow and the mixture is heated to reflux for 3 days. The solvent and excess starting material are removed by distillation under reduced pressure and the residue is crystallized from n-chlorohexane. 0.25 g (20%) product is obtained as a white solid.

lithium tris(4,5,6,7-tetrafluoro-3-(perfluorophenyl)-1H-indazol-1-yl)hydroborate (PB-3)

Step 1: 4,5,6,7-tetrafluoro-3-(perfluorophenyl)-1H-indazole

(24) ##STR00009##

(25) 20.0 g (54.8 mmol) perfluorobenzophenone are dissolved in 200 mL toluene. 4.0 mL (4.11 g, 82.1 mmol, ca. 1.5 eq) hydrazine-monohydrate is added dropwise to the ice-cooled solution. 40 g sodium sulfate are added and the mixture is heated to reflux for 2 days. After cooling, 10 mL acetone are added to the reaction mixture and the resulting slurry is stirred for 1 h at room temperature. The solid is filtered off, thoroughly washed with 4×50 mL toluene, organic fractions are combined and washed two times with saturated aqueous sodium hydrogen carbonate. The solvent is removed under reduced pressure and the residue purified by column chromatography. 7.92 g (41%) product are obtained as a pale yellow solid.

(26) GC-MS: confirms the expected M/z (mass/charge) ratio 356

Step 2: lithium tris(4,5,6,7-tetrafluoro-3-(perfluorophenyl)-1-indazol-1-yl)hydroborate

(27) ##STR00010##

(28) 1.02 g (2.86 mmol, 3.0 eq) 4,5,6,7-tetrafluoro-3-(perfluorophenyl)-1H-indazole are dissolved in 5 mL chlorobenzene in a baked-out Schlenk flask. Freshly pulverized lithium borohydride (21 mg, 0.95 mmol, 1.0 eq) is added under Ar counter-flow. The mixture is heated to 150° C. for 2 days and cooled to room temperature. The solvent is removed under reduced pressure and the residue dried in high vacuum. The crude is further purified by drying in a bulb to bulb apparatus at a temperature about 150° C. and a pressure about 12 Pa. 0.57 g (70%) product are obtained as an off white solid.

Lithium tris(3-cyano-5,6-difluoro-1H-indazol-1-yl)hydroborate (PB-4)

(29) ##STR00011##

(30) Freshly pulverized lithium borohydride (15 mg, 0.7 mmol, 1.0 eq) is placed in a baked-out pressure tube, 0.5 g (2.79 mmol, 4.0 eq) 5,6-difluoro-1H-indazole-3-carbonitrile are added under Ar counter-flow and washed down with 1 mL toluene. The pressure tube is closed and heated to a temperature about 160° C. for ca 21 h. After cooling to room temperature, the mixture is treated with 5 mL hexane in an ultra-sonic bath for ca 30 min. The precipitated solid is filtered off and washed with hexane (20 mL in total). After drying, 0.48 g yellowish solid are obtained.

zinc(II) tris(3,5-bis(trifluoromethyl)-1H-pyrazol-1-yl)hydroborate (PB-5)

(31) ##STR00012##

(32) 0.57 g (0.91 mmol) lithium tris(3,5-bis(trifluoromethyl)-1H-pyrazol-1-yl)hydroborate are dissolved in 6 mL N,N-dimethyl formamide. An aqueous solution of 62 mg zinc dichloride in 1 mL water is added dropwise. 20 mL water are further added and the mixture is treated in an ultra-sonic bath for 2 h. The precipitate is filtered off and dried in high vacuum. 0.485 g (82%) product are obtained as a white solid.

Exemplary Compound E3

A Precursor Compound E2 has been Prepared According to Scheme 1

(33) ##STR00013##

Step 1: Synthesis of 1,1,1-trifluoro-N-(perfluorophenyl)methanesulfonamide

(34) A 250 mL Schlenk flask is heated in vacuum and, after cooling, purged with nitrogen. Per-fluoroaniline is dissolved in 100 mL toluene and the solution cooled to −80° C. A 1.7 M t-butyl lithium solution in hexane is added dropwise via syringe over 10 min. The reaction solution changes from clear to cloudy and is stirred for 1 h at −80° C. After that, the solution is allowed to warm to −60° C. and 1.1 eq of trifluoromethanesulfonic anhydride is added dropwise to the solution. Then, the cooling bath is removed and the reaction mixture is allowed to warm slowly to ambient temperature and stirred overnight, whereby the color changes to light orange. Additionally, a white solid forms. The precipitated by-product lithium trifluoromethane sulfonate is filtered off by suction filtration over a sintered glass filter and washed with 2×30 mL toluene and 30 mL n-hexane. The orange filtrate is evaporated and dried in high vacuum, forming crystals. The crude product is then purified by bulb-to-bulb distillation (135° C. @ 1.2×10−1 mbar), resulting in a crystalline colorless solid (main fraction).

(35) .sup.1H NMR [d.sup.6-DMSO, ppm] δ: 13.09 (s, 1H, N—H).

(36) .sup.13C{.sup.1H} NMR [d.sup.6-DMSO, ppm] δ: 116.75 (m, C.sub.i-C.sub.6F.sub.5), 120.74 (q, .sup.1J.sub.CF=325 Hz, CF.sub.3), 136.39, 138.35 (2 m, .sup.2J.sub.CF=247 Hz, m-C.sub.6F.sub.5), 137.08, 139.06 (2 m, .sup.2J.sub.CF=247 Hz, p-C.sub.6F.sub.5), 142.98, 144.93 (2 m, .sup.2J.sub.CF=247, Hz o-C.sub.6F.sub.5).

(37) .sup.19F NMR [d.sup.6-DMSO, ppm]δ: −77.45 (m, CF.sub.3), −148.12 (m, C.sub.6F.sub.5), −160.79 (n, p-C.sub.6F.sub.5), −164.51 (m, C.sub.6F.sub.5).

(38) ESI-MS: m/z-neg=314 (M-H).

(39) EI-MS: m/z=315 (M), 182 (M-SO.sub.2CF.sub.3), 69 (CF.sub.3).

Step 2: Synthesis of bis((1,1,1-trifluoro-N-(perfluorophenyl)methyl)-sulfonamido)zinc

(40) A 100 mL Schlenk flask is heated in vacuum and, after cooling, purged with nitrogen. 1,1,1-trifluoro-N-(perfluorophenyl) methane sulfonamide is dissolved in to mL toluene and 0.5 eq of diethyl zinc in hexane is added dropwise to the solution via syringe at ambient temperature. During the addition, a fog forms in the flask and the reaction solution becomes jelly and cloudy. The solution is stirred for further 30 min at this temperature. After that, 30 mL n-hexane are added and a white precipitate forms, which is subsequently filtered over a sintered glass filter (pore 4) under inert atmosphere. The filter cake is twice washed with 15 mL n-hexane and dried in high vacuum at 100° C. for a h.

(41) Yield: 660 mg (0.95 mmol, 60% based on 1,1,1-trifluoro-N-perfluorophenyl) methane sulfonamide) as a white solid.

(42) .sup.13C{.sup.1H} NMR [d.sup.6-DMSO, ppm] δ: 121.68 (q, .sup.1J.sub.CF=328 Hz, CF.sub.3), 123.56 (m, C.sub.i-C.sub.6F.sub.5), 133.98, 135.91 (2 m, .sup.2J.sub.CF=243 Hz, p-C.sub.6F.sub.5), 136.15, 138.13 (2 m, .sup.2J.sub.CF=249 Hz, m-C.sub.6F.sub.5), 142.33, 144.24 (2 m, .sup.2J.sub.CF=240, Hz o-C.sub.6F.sub.5).

(43) .sup.19F NMR [d.sup.6-DMSO, ppm] δ: −77.52 (m, CF.sub.3), −150.43 (m, C.sub.6F.sub.5), −166.77 (m, C.sub.6F.sub.5), −168.23 (m, p-C.sub.6F.sub.5).

(44) ESI-MS: m/z-neg=314 (M-Zn-L).

(45) EI-MS: m/z=692 (M), 559 (M-SO.sub.2CF.sub.3) 315 (C.sub.6F.sub.5NHSO.sub.2CF.sub.3), 182 (C.sub.6F.sub.5NH), 69 (CF.sub.3).

Exemplary Compound E3

(46) 9.1 g E2 is sublimed at the temperature 240° C. and pressure 30.sup.−3 Pa.

(47) yield 5.9 g (65%).

(48) The sublimed material forms colorless crystals. One crystal of an appropriate shape and size (0.094×0.052×0.043 mm.sup.3) has been closed under Ar atmosphere in a glass capillary and analyzed on Kappa Apex II diffractometer (Bruker-AXS, Karlsruhe, Germany) with mono-chromatic X-ray radiation from a source provided with molybdenum cathode (λ=71.073 pm). Overall 37362 reflexions were collected within the theta range 1.881 to 28.306. The structure was resolved by direct method (SHELXS-97, Sheldriek, 2008) and refined with a full-matrix least-squares method (SHELXL-2014/7, Olex2 (Dolomanov, 2017).

(49) TABLE-US-00001 TABLE 1 auxiliary materials for device examples Compound Structure F.sub.1 (CAS 1242056-42-3) F.sub.2 (CAS 1440545-225-1) F.sub.3 (CAS 597578-38-6) F.sub.4 (CAS 1207671-22-4) F.sub.5 CAS 1638271-85-8 F6 CAS 721969-94-4 PD.sub.2 2,2′,2″-(cyclopropane-1,2,3-triylidene)-tris[2- (4-cyanoperfluorophenyl)-acetonitrile] (CAS1224447-88-4) 0 LiQ 8-Hydroxyquinolato lithium (CAS 850918-68-2) CN-HAT (CAS 105598-27-4)

(50) ABH-113 is an emitter host and NUBD-370 and DB-200 are blue fluorescent emitter dopants, all commercially available from SFC, Korea.

(51) Before use in vacuum deposition processes, the auxiliary materials as well as the tested compounds were purified by preparative vacuum sublimation.

DEVICE EXAMPLES

Example 1 (Bottom Emitting White OLED Pixel, Comprising a Metal Complex or Metal Salt as a p-Dopant Concentrated in a Neat Hole Generating Sub-Layer)

(52) On a glass substrate provided with an ITO anode having thickness go nm, there were subsequently deposited ho nm hole injection layer made of F1 doped with 8 wt % PD-2; 140 nm thick undoped hole transport layer made of neat F1; 20 nm thick first emitting layer formed of ABH113 doped with 3 wt % BD200 (both supplied by SFC, Korea); 25 nm thick first electron transport layer made of neat F2; 10 nm thick electron-generating part of the charge-generating layer (n-CGL) made of F3 doped with 5 wt % Yb; 2 nm thick interlayer made of F4; 30 nm thick hole-generating part of the charge-generating layer (p-CGL) made of PB-1; 10 nm thick second hole transport layer made of neat F; 20 nm second emitting layer of the same thickness and composition as the first emitting layer; 25 nm thick first electron transport layer made of neat F2; 10 nm thick electron injection layer (EIL) made of F3 doped with 5 wt % Yb; too nm Al cathode.

(53) All layers were deposited by vacuum thermal evaporation (VTE).

(54) At the current density 10 mA/cm.sup.2, the operational voltage of the device 8 V and the observed luminance were well comparable with the same device comprising a commercial state-of-art p-dopant instead of PB-1. An accurate calibration necessary for efficiency evaluation was omitted within this preliminary experiment.

Example 2 (Bottom Emitting Blue OLED Pixel Comprising a Metal Complex or Metal Salt as a p-Dopant Concentrated in a Neat Hole Injecting Sub-Layer)

(55) On the same glass substrate provided with an ITO anode as in the Example 1, following layers were subsequently deposited by VTE: 10 nm hole injection layer made of the compound PB-1; 120 nm thick HTL made of neat F1; 20 nm EML made of ABH113 doped with 3 wt % NUBD370 (both supplied by SFC, Korea), 36 nm EIL/ETL made of F2 doped with 50 wt % LiQ; 100 nm Al cathode.

(56) Comparative device comprised the HIL made of the compound CN-HAT (CAS 105598-27-4) instead of PB-1.

(57) The inventive device achieved current density 15 mA/cm and EQE 5.4% at a voltage 5.2 V, whereas the comparative device operated at 5.4 V with EQE 4.9%.

Example 3 (Blue Display Pixel Comprising a Metal Complex or a Metal Salt as a p-Dopant Concentrated in a Neat Hole Injection Sub-Layer)

(58) Table 2a schematically describes the model device

(59) TABLE-US-00002 TABLE 2a c d Material [wt %] [nm] ITO 100 90 p-dopant 100  3* F.sub.1 100 120  ABH.sub.113:NUBD.sub.370 97:3  20 F.sub.2:LiQ 50:50 36 Al 100 100  *E.sub.3 has been tested also as a layer only 1 nm thin.

(60) The results for LiTFSI as a reference and one exemplary p-dopant are given in Table 2b

(61) TABLE-US-00003 TABLE 2b U* EQE* U(50 h)-U(1 h) ** [V] [%] CIE-y* [V] 3 nm LiTFSI 5.28 6.6 0.090 0.275 3 nm E.sub.3 5.38 5.7 0.094 0.246 1 nm E.sub.3 5.11 5.4 0.096 0.040 *j = 15 mA/cm.sup.2 ** j = 30 mA/cm.sup.2

Example 4 (Blue Display Pixel Comprising a Metal Complex or a Metal Salt as a p-Dopant Concentrated in a Neat Hole Generation Sub-Layer)

(62) Table 3a schematically describes the model device.

(63) TABLE-US-00004 TABLE 3a c d Material [wt %] [nm] ITO 100 90 F.sub.1:PD-2 92:8 10 F.sub.1 100 145 ABH.sub.113:BD.sub.200 97:3 20 F.sub.5 100 25 F.sub.6:Li 99:1 10 ZnPc 100 2 p-dopant 100 1 F.sub.1 100 30 ABH.sub.113:BD.sub.200 97:3 20 F.sub.5 100 26 F6:Li 99:1 10 Al 100 100

(64) The results for LiTFSI as a reference and one exemplary p-dopant are given in Table 3b

(65) TABLE-US-00005 TABLE 3b U* EQE* [V] [%] CIE-y* 1 nm LiTFSI 10.65 6.3 0.066 1 nm E.sub.3 7.52 13.5 0.083 *j = 10 mA/cm.sup.2 **j = 30 mA/cm.sup.2

(66) The features disclosed in the foregoing description and in the dependent claims may, both separately and in any combination thereof, be material for realizing the aspects of the disclosure made in the independent claims, in diverse forms thereof.

(67) Key symbols and abbreviations used throughout the application: CV cyclic voltammetry DSC differential scanning calorimetry EBL electron blocking layer EIL electron injecting layer EML emitting layer eq. equivalent ETL electron transport layer ETM electron transport matrix Fc ferrocene Fc.sup.+ ferricenium HBL hole blocking layer HIL hole injecting layer HOMO highest occupied molecular orbital HPLC high performance liquid chromatography HTL hole transport layer p-HTL p-doped hole transport layer HTM hole transport matrix ITO indium tin oxide LUMO lowest unoccupied molecular orbital mol % molar percent NMR nuclear magnetic resonance OLED organic light emitting diode OPV organic photovoltaics QE quantum efficiency R.sub.f retardation factor in TLC RGB red-green-blue TCO transparent conductive oxide TFr thin film transistor T.sub.g glass transition temperature TLC thin layer chromatography wt % weight percent