Charge-transporting varnish and organic electroluminescent element

Abstract

Provided is a charge-transporting varnish which comprises an amide compound containing fluorine atoms and represented by formula (1) and a charge-transporting substance. ##STR00001##
[In the formula, Ar.sup.1 represents a group represented by any of formulae (1-1) to (1-9) and Ar.sup.2 and Ar.sup.3 each represent a given fluorinated aryl or aralkyl group.] ##STR00002##

Claims

1. A charge-transporting varnish comprising a fluorine atom-containing amide compound of formula (1) below and a charge-transporting substance, ##STR00042## wherein Ar.sup.1 is a group of any of formulas (1-1) to (1-9) below, ##STR00043## wherein each R is independently a cyano group, a nitro group, a halogen atom, an alkyl group of 1 to 20 carbon atoms or a haloalkyl group of 1 to 20 carbon atoms, Cb.sup.1 and Cb.sup.2 each are independently an alkyl group of 1 to 20 carbon atoms or an aryl group of 6 to 20 carbon atoms, n is an integer from 0 to 4, and m is an integer from 0 to 3; and Ar.sup.2 and Ar.sup.3 are each independently a fluoroaryl group of 6 to 20 carbon atoms which may be substituted with a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, an alkyl group of 1 to 20 carbon atoms, a fluoroalkyl group of 1 to 20 carbon atoms or a fluoroalkoxy group of 1 to 20 carbon atoms; an aryl group of 6 to 20 carbon atoms which is substituted with a fluoroalkyl group of 1 to 20 carbon atoms, a fluorocycloalkyl group of 3 to 20 carbon atoms, a fluorobicycloalkyl group of 4 to 20 carbon atoms, a fluoroalkenyl group of 2 to 20 carbon atoms or a fluoroalkynyl group of 2 to 20 carbon atoms, and which may be additionally substituted with a cyano group, a halogen atom or a fluoroalkoxy group of 1 to 20 carbon atoms; a fluoroaralkyl group of 7 to 20 carbon atoms which may be substituted with a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a fluoroalkoxy group of 1 to 20 carbon atoms, a fluoroalkyl group of 1 to 20 carbon atoms, a fluorocycloalkyl group of 3 to 20 carbon atoms, a fluorobicycloalkyl group of 4 to 20 carbon atoms, a fluoroalkenyl group of 2 to 20 carbon atoms or a fluoroalkynyl group of 2 to 20 carbon atoms; or an aralkyl group of 7 to 20 carbon atoms which is substituted with a fluoroalkyl group of 1 to 20 carbon atoms, a fluorocycloalkyl group of 3 to 20 carbon atoms, a fluorobicycloalkyl group of 4 to 20 carbon atoms, a fluoroalkenyl group of 2 to 20 carbon atoms or a fluoroalkynyl group of 2 to 20 carbon atoms, and which may be additionally substituted with a cyano group, a halogen atom or a fluoroalkoxy group of 1 to 20 carbon atoms.

2. The charge-transporting varnish of claim 1, wherein Ar.sup.2 and Ar.sup.3 are each independently a fluoroaryl group of 6 to 20 carbon atoms which may be substituted with a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, an alkyl group of 1 to 20 carbon atoms, a fluoroalkyl group of 1 to 20 carbon atoms or a fluoroalkoxy group of 1 to 20 carbon atoms; or an aryl group of 6 to 20 carbon atoms which is substituted with a fluoroalkyl group of 1 to 20 carbon atoms, a fluorocycloalkyl group of 3 to 20 carbon atoms, a fluorobicycloalkyl group of 4 to 20 carbon atoms, a fluoroalkenyl group of 2 to 20 carbon atoms or a fluoroalkynyl group of 2 to 20 carbon atoms, and which may be additionally substituted with a cyano group, a halogen atom or a fluoroalkoxy group of 1 to 20 carbon atoms.

3. The charge-transporting varnish of claim 2, wherein Ar.sup.2 and Ar.sup.3 are each independently a phenyl group which is substituted with three or more fluorine atoms and may be substituted with a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, an alkyl group of 1 to 20 carbon atoms, a fluoroalkyl group of 1 to 20 carbon atoms or a fluoroalkoxy group of 1 to 20 carbon atoms; or a 2-(trifluoromethyl)phenyl, 3-(trifluoromethyl)phenyl, 4-(trifluoromethyl)phenyl, 4-ethoxy-3-(trifluoromethyl)phenyl, 3-fluoro-4-trifluoromethylphenyl, 4-fluoro-3-trifluoromethylphenyl, 4-fluoro-2-trifluoromethylphenyl, 2-fluoro-5-(trifluoromethyl)phenyl, 3-fluoro-5-(trifluoromethyl)phenyl, 3,5-di(trifluoromethyl)phenyl, 2,4,6-tri(trifluoromethyl)phenyl, 4-(pentafluoroethyl)phenyl, 4-(3,3,3-trifluoropropyl)phenyl, 2,3,5,6-tetrafluoro-4-trifluoromethylphenyl, 4-(perfluorovinyl)phenyl, 4-(perfluoropropenyl)phenyl or 4-(perfluorobutenyl)phenyl group.

4. The charge-transporting varnish of any one of claims 1 to 3, wherein Ar.sup.2 and Ar.sup.3 are identical groups.

5. The charge-transporting varnish of claim 1, wherein n and m are both 0.

6. The charge-transporting varnish of claim 1, wherein Ar.sup.1 is a group of formula (1-1), (1-2), (1-3), (1-7) or (1-9).

7. The charge-transporting varnish of claim 1, further comprising a dopant.

8. A charge-transporting thin film produced using the charge-transporting varnish of claim 1.

9. An organic electroluminescent device comprising the charge-transporting thin film of claim 8.

10. A fluorine atom-containing amide compound of formula (1) below, ##STR00044## wherein Ar.sup.1 is a group of any of formulas (1-1) to (1-9) below, ##STR00045## wherein each R is independently a cyano group, a nitro group, a halogen atom, an alkyl group of 1 to 20 carbon atoms or a haloalkyl group of 1 to 20 carbon atoms, Cb.sup.1 and Cb.sup.2 each are independently an alkyl group of 1 to 20 carbon atoms or an aryl group of 6 to 20 carbon atoms, n is an integer from 0 to 4, and m is an integer from 0 to 3; and Ar.sup.2 and Ar.sup.3 are each independently a fluoroaryl group of 6 to 20 carbon atoms which may be substituted with a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, an alkyl group of 1 to 20 carbon atoms, a fluoroalkyl group of 1 to 20 carbon atoms or a fluoroalkoxy group of 1 to 20 carbon atoms; an aryl group of 6 to 20 carbon atoms which is substituted with a fluoroalkyl group of 1 to 20 carbon atoms, a fluorocycloalkyl group of 3 to 20 carbon atoms, a fluorobicycloalkyl group of 4 to 20 carbon atoms, a fluoroalkenyl group of 2 to 20 carbon atoms or a fluoroalkynyl group of 2 to 20 carbon atoms, and which may be additionally substituted with a cyano group, a halogen atom or a fluoroalkoxy group of 1 to 20 carbon atoms; a fluoroaralkyl group of 7 to 20 carbon atoms which may be substituted with a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a fluoroalkoxy group of 1 to 20 carbon atoms, a fluoroalkyl group of 1 to 20 carbon atoms, a fluorocycloalkyl group of 3 to 20 carbon atoms, a fluorobicycloalkyl group of 4 to 20 carbon atoms, a fluoroalkenyl group of 2 to 20 carbon atoms or a fluoroalkynyl group of 2 to 20 carbon atoms; or an aralkyl group of 7 to 20 carbon atoms which is substituted with a fluoroalkyl group of 1 to 20 carbon atoms, a fluorocycloalkyl group of 3 to 20 carbon atoms, a fluorobicycloalkyl group of 4 to 20 carbon atoms, a fluoroalkenyl group of 2 to 20 carbon atoms or a fluoroalkynyl group of 2 to 20 carbon atoms, and which may be additionally substituted with a cyano group, a halogen atom or a fluoroalkoxy group of 1 to 20 carbon atoms; exclusive of combinations that represent fluorine atom-containing amide compounds of any of formulas (K1) to (K18) below: ##STR00046## ##STR00047##

11. The fluorine atom-containing amide compound of claim 10, wherein Ar.sup.2 and Ar.sup.3 are each independently a fluoroaryl group of 6 to 20 carbon atoms which may be substituted with a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, an alkyl group of 1 to 20 carbon atoms, a fluoroalkyl group of 1 to 20 carbon atoms or a fluoroalkoxy group of 1 to 20 carbon atoms; or an aryl group of 6 to 20 carbon atoms which is substituted with a fluoroalkyl group of 1 to 20 carbon atoms, a fluorocycloalkyl group of 3 to 20 carbon atoms, a fluorobicycloalkyl group of 4 to 20 carbon atoms, a fluoroalkenyl group of 2 to 20 carbon atoms or a fluoroalkynyl group of 2 to 20 carbon atoms, and which may be additionally substituted with a cyano group, a halogen atom or a fluoroalkoxy group of 1 to 20 carbon atoms.

12. The fluorine atom-containing amide compound of claim 11, wherein Ar.sup.2 and Ar.sup.3 are each independently a phenyl group which is substituted with three or more fluorine atoms and may be substituted with a cyano group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, an alkyl group of 1 to 20 carbon atoms, a fluoroalkyl group of 1 to 20 carbon atoms or a fluoroalkoxy group of 1 to 20 carbon atoms; or a 2-(trifluoromethyl)phenyl, 3-(trifluoromethyl)phenyl, 4-(trifluoromethyl)phenyl, 4-ethoxy-3-(trifluoromethyl)phenyl, 3-fluoro-4-trifluoromethylphenyl, 4-fluoro-3-trifluoromethylphenyl, 4-fluoro-2-trifluoromethylphenyl, 2-fluoro-5-(trifluoromethyl)phenyl, 3-fluoro-5-(trifluoromethyl)phenyl, 3,5-di(trifluoromethyl)phenyl, 2,4,6-tri(trifluoromethyl)phenyl, 4-(pentafluoroethyl)phenyl, 4-(3,3,3-trifluoropropyl)phenyl, 2,3,5,6-tetrafluoro-4-trifluoromethylphenyl, 4-(perfluorovinyl)phenyl, 4-(perfluoropropenyl)phenyl or 4-(perfluorobutenyl)phenyl group.

13. The fluorine atom-containing amide compound of any one of claims 10 to 12, wherein Ar.sup.2 and Ar.sup.3 are identical groups.

14. The fluorine atom-containing amide compound of claim 10, wherein n and m are both 0.

15. The fluorine atom-containing amide compound of claim 10, wherein Ar.sup.1 is a group of formula (1-1), (1-2), (1-3), (1-7) or (1-9).

Description

EXAMPLES

(1) Synthesis Examples, Working Examples and Comparative Examples are given below to more concretely illustrate the invention, although the invention is not limited by these Examples. The equipment used was as follows.

(2) TABLE-US-00010 (1) .sup.1H-NMR Measurement: 400NB NMR system, from Varian, Inc. (2) Substrate Cleaning: Substrate cleaning machine (reduced- pressure plasma system), from Choshu Industry Co., Ltd. (3) Varnish Coating: MS-A100 Spin Coater, from Mikasa Co., Ltd. (4) Measurement of Contact Contact angle meter, from Kyowa Angle: Interface Science Co., Ltd. (5) Film Thickness Measurement: Surfcorder ET-4000 microfigure measuring instrument, from Kosaka Laboratory, Ltd. (6) Fabrication of Organic EL C-E2L1G1-N Multifunction Vapor Device: Deposition System, from Choshu Industry Co., Ltd. (7) Measurement of Organic EL I-V-L Measurement System from Device Brightness: Tech World, Inc. (8) Measurement of Organic EL PEL-105S Organic EL Brightness Device Longevity: Life EvaluationSystem, from EHC K.K. [1] Compound Synthesis

[Synthesis Example 1] Synthesis of Amide Compound A

(3) ##STR00034##

(4) A flask was charged with 2.00 g of N1-(4-aminophenyl)benzene-1,4-diamine, 20 mL of toluene and 3.34 mL of triethylamine, following which the flask interior was flushed with nitrogen, 6.36 g of 2,3,4,5-tetrafluorobenzoyl chloride was added dropwise and the system was stirred at room temperature for 2 hours. The reaction mixture was filtered and the resulting filtered matter was dried, after which it was dissolved in N,N-dimethylformamide. The resulting solution was added dropwise to 400 mL of deionized water, following which stirring was carried out at room temperature. The suspension was filtered and the filtered matter thus obtained was dried, giving the target Amide Compound A (yield, 3.82 g). The .sup.1H-NMR measurement results are shown below.

(5) .sup.1H-NMR (400 MHz, DMSO-d6): 10.43 (s, 2H), 8.18 (s, 1H), 7.73-7.79 (m, 2H), 7.56 (d, J=8.8 Hz, 4H), 7.06 (d, J=8.8 Hz, 4H).

[Synthesis Example 2] Synthesis of Amide Compound B

(6) ##STR00035##

(7) A flask was charged with 2.00 g of 4,4-(9H-fluorene-9,9-diyl)dianiline, 40 mL of toluene and 2.07 mL of triethylamine, following which the flask interior was flushed with nitrogen, 3.01 g of 2,3,4,5-tetrafluorobenzoyl chloride was added dropwise and the system was stirred at room temperature for 4 hours. The reaction mixture was filtered and the resulting filtered matter was dried, after which it was dissolved in N,N-dimethylformamide. The resulting solution was added dropwise to 450 mL of deionized water, following which stirring was carried out at room temperature. The suspension was filtered and the filtered matter thus obtained was dried, giving the target Amide Compound B (yield, 3.81 g). The .sup.1H-NMR measurement results are shown below.

(8) .sup.1H-NMR (400 MHz, DMSO-d6): 10.58 (s, 2H), 7.91 (d, J=7.6 Hz, 2H), 7.67-7.73 (m, 2H), 7.54 (d, J=8.8 Hz, 4H), 7.44 (d, J=7.6 Hz, 2H), 7.38 (t, J=7.6 Hz, 2H), 7.30 (t, J=7.6 Hz, 2H), 7.09 (d, J=8.8 Hz, 4H).

[Synthesis Example 3] Synthesis of Amide Compound C

(9) ##STR00036##

(10) A flask was charged with 1.00 g of di(4-aminophenyl) ether, 20 mL of toluene and 1.80 mL of triethylamine, following the flask interior was flushed with nitrogen, 2.59 g of 2,3,4,5-tetrafluorobenzoyl chloride was added dropwise and the system was stirred at room temperature for 2 hours. The reaction mixture was filtered and the resulting filtered matter was dried, after which it was dissolved in N,N-dimethylformamide. The resulting solution was added dropwise to 300 mL of deionized water, following which stirring was carried out at room temperature. The suspension was filtered and the filtered matter thus obtained was dried, giving the target Amide Compound C (yield, 2.04 g). The .sup.1H-NMR measurement results are shown below.

(11) .sup.1H-NMR (400 MHz, DMSO-d6): 10.60 (s, 2H), 7.72-7.78 (m, 2H), 7.67 (d, J=8.8 Hz, 4H), 7.01 (d, J=8.8 Hz, 4H).

[Synthesis Example 4] Synthesis of Amide Compound D

(12) ##STR00037##

(13) A flask was charged with 1.00 g of N1-(4-aminophenyl)-N1-methylbenzene-1,4-diamine, 40 mL of toluene and 1.70 mL of triethylamine, following which the flask interior was flushed with nitrogen, 2.41 g of 2,3,4,5-tetrafluorobenzoyl chloride was added dropwise and the system was stirred at room temperature for 20 hours. The reaction mixture was filtered and the resulting filtered matter was dried, after which it was dissolved in N,N-dimethylformamide. The resulting solution was added dropwise to 250 mL of deionized water, following which stirring was carried out at room temperature. The suspension was filtered and the filtered matter thus obtained was dried, giving the target Amide Compound D (yield, 2.40 g). The .sup.1H-NMR measurement results are shown below.

(14) .sup.1H-NMR (400 MHz, THF-d8): 9.40 (s, 2H), 7.59-7.65 (m, 6H), 6.99 (d, J=8.8 Hz, 4H), 3.29 (s, 3H).

[Synthesis Example 5] Synthesis of Amide Compound E

(15) ##STR00038##

(16) A flask was charged with 0.96 g of 9H-carbazole-3,6-diamine, 20 mL of toluene and 1.62 mL of triethylamine, following which the flask interior was flushed with nitrogen, 2.55 g of 2,3,4,5-tetrafluorobenzoyl chloride was added dropwise and the system was stirred at room temperature for 2 hours. The reaction mixture was filtered and the resulting filtered matter was dried, after which it was dissolved in N,N-dimethylformamide. The resulting solution was added dropwise to 250 mL of deionized water, following which stirring was carried out at room temperature. The suspension was filtered and the filtered matter thus obtained was suspended in and washed with isopropanol and then dried, giving the target Amide Compound E (yield, 1.86 g). The .sup.1H-NMR measurement results are shown below.

(17) .sup.1H-NMR (400 MHz, DMSO-d6): 11.27 (s, 1H), 10.58 (s, 2H), 8.46 (s, 2H), 7.77-7.82 (m, 2H), 7.58 (dd, J=8.8, 2.0 Hz, 2H), 7.45 (d, J=8.8 Hz, 2H).

[Synthesis Example 6] Synthesis of Amide Compound F

(18) ##STR00039##

(19) A flask was charged with 1.00 g of N1-(4-aminophenyl)benzene-1,4-diamine, 30 mL of toluene and 1.8 mL of triethylamine, following which the flask interior was flushed with nitrogen, 1.70 g of benzoyl chloride was added dropwise and the system was stirred at room temperature for 1 hour. The reaction mixture was filtered and the resulting filtered matter was dried, after which it was dissolved in N,N-dimethylformamide. The resulting solution was added dropwise to 200 mL of deionized water, following which stirring was carried out at room temperature. The suspension was filtered, and the filtered matter thus obtained was washed with ethanol and then dried, giving the target Amide Compound F (yield, 1.46 g). The .sup.1H-NMR measurement results are shown below.

(20) .sup.1H-NMR (400 MHz, THF-d8): 9.20 (s, 2H), 7.91 (d, J=7.2 Hz, 4H), 7.63 (d, J=7.6 Hz, 4H), 7.40-7.48 (m, 6H), 7.19 (s, 1H), 7.01 (d, J=7.6 Hz, 4H).

[Synthesis Example 7] Synthesis of Aniline Derivative X

(21) ##STR00040##

(22) A flask was charged with 4,4-diaminodiphenylamine (3.18 g, 16.0 mmol), 4-bromotriphenylamine (11.4 g, 35.2 mmol), Pd(dba).sub.2 (0.185 g, 0.322 mmol) and t-BuONa (3.38 g, 35.2 mmol) and the flask interior was flushed with nitrogen, following which toluene (200 mL) and PhP(t-Bu).sub.2 (0.142 g, 0.639 mmol) were added and the system was stirred at 80 C. for 5 hours. The reaction mixture was cooled to room temperature, following which water was added, thereby stopping the reaction, and the organic layer was separated off by liquid separation. The organic layer was washed with saturated saline water and dried over MgSO.sub.4, following which the solvent was distilled off under reduced pressure, giving a crude product. The crude product was purified by silica gel column chromatography (toluene/ethyl acetate), giving the target Aniline Derivative X (yield, 6.83 g). [2] Preparation of Charge-Transporting Varnishes

[Working Example 1-1] Preparation of Charge-Transporting Varnish A

(23) Charge-Transporting Varnish A was prepared by dissolving 0.051 g of Amide Compound A synthesized in Synthesis Example 1, 0.129 g of Aniline Derivative X synthesized in Synthesis Example 7 and 0.383 g of Arylsulfonic Acid A of the formula shown below, under a nitrogen atmosphere, in a mixed solvent of 6.7 g of 1,3-dimethyl-2-imidazolidinone (DMI), 10 g of cyclohexanol (CHA) and 3.3 g of propylene glycol (PG). Arylsulfonic Acid A was synthesized in accordance with WO 2006/025342.

(24) ##STR00041##

[Working Example 1-2] Preparation of Charge-Transporting Varnish B

(25) Charge-Transporting Varnish B was prepared by dissolving 0.051 g of Amide Compound B synthesized in Synthesis Example 2, 0.129 g of Aniline Derivative X synthesized in Synthesis Example 7 and 0.383 g of Arylsulfonic Acid A, under a nitrogen atmosphere, in a mixed solvent of 6.7 g of DMI, 10 g of CHA and 3.3 g of PG.

[Working Example 1-3] Preparation of Charge-Transporting Varnish C

(26) Charge-Transporting Varnish C was prepared by dissolving 0.051 g of Amide Compound C synthesized in Synthesis Example 3, 0.129 g of Aniline Derivative X synthesized in Synthesis Example 7 and 0.383 g of Arylsulfonic Acid A, under a nitrogen atmosphere, in a mixed solvent of 6.7 g of DMI, 10 g of CHA and 3.3 g of PG.

[Working Example 1-4] Preparation of Charge-Transporting Varnish D

(27) Charge-Transporting Varnish D was prepared by dissolving 0.051 g of Amide Compound D synthesized in Synthesis Example 4, 0.129 g of Aniline Derivative X synthesized in Synthesis Example 7 and 0.383 g of Arylsulfonic Acid A, under a nitrogen atmosphere, in a mixed solvent of 6.7 g of DMI, 10 g of CHA and 3.3 g of PG.

[Working Example 1-5] Preparation of Charge-Transporting Varnish E

(28) Charge-Transporting Varnish E was prepared by dissolving 0.051 g of Amide Compound E synthesized in Synthesis Example 5, 0.129 g of Aniline Derivative X synthesized in Synthesis Example 7 and 0.383 g of Arylsulfonic Acid A, under a nitrogen atmosphere, in a mixed solvent of 6.7 g of DMI, 10 g of CHA and 3.3 g of PG.

Comparative Example 1-1

Preparation of Charge-Transporting Varnish F

(29) Charge-Transporting Varnish F was prepared by dissolving 0.051 g of Amide Compound F synthesized in Synthesis Example 6, 0.129 g of Aniline Derivative X synthesized in Synthesis Example 7 and 0.383 g of Arylsulfonic Acid A, under a nitrogen atmosphere, in a mixed solvent of 6.7 g of DMI, 10 g of CHA and 3.3 g of PG. [3] Production of Thin Films and Measurement of Contact Angle.

(30) The contact angle was measured by the following method for the charge-transporting varnishes produced in Working Examples 1-1 to 1-5 and Comparative Example 1.

(31) In each case, the charge-transporting varnish was spin-coated onto an indium-tin oxide (ITO) substrate to form a film, dried in open air at 80 C. on a hot plate for 1 minute and then baked under applied heat at 230 C. for 15 minutes, thereby producing a thin film. The contact angle of cyclohexylbenzene on the resulting thin film was measured. The results are shown in Table 10.

(32) TABLE-US-00011 TABLE 10 Charge- Contact angle of transporting cyclohexylbenzene varnish () Working Example 1-1 A 2.8 Working Example 1-2 B 2.0 Working Example 1-3 C 2.4 Working Example 1-4 D 2.2 Working Example 1-5 E 3.0 Comparative Example 1 F 29.3

(33) When the contact angle of the solvent used in the upper layer material is 10 or more, crawling of the upper layer material may occur at the time of deposition, as a result of which a uniform film may not be obtainable. As shown in Table 10, the contact angle of the solvent on the thin film produced from the charge-transporting varnish in Comparative Example 1 is very high, and so there is a risk of the solvent used in the upper layer material being repelled. On the other hand, the contact angle of the solvent on the thin films produced from the charge-transporting varnishes in Working Examples 1-1 to 1-5 which include the fluorine atom-containing amide compound of the invention is 3 or less in each case. Hence it is expected that crawling will not arise at the time of deposition and that the coatability of the upper layer will be good, resulting in formation of the upper layer material into a uniform film. [4] Device Fabrication and Evaluation of Device Characteristics

(34) In the following Working Examples and Comparative Examples, a glass substrate with dimensions of 25 mm25 mm0.7 mm (t) and having ITO patterned on the surface to a film thickness of 150 nm was used as the ITO substrate. Prior to use, impurities on the surface were removed with an O.sub.2 plasma cleaning system (150 W, 30 seconds). [4-1] Fabrication of Single-Layer Devices (SLD) and Evaluation of Device Characteristics

Working Example 2-1

(35) The varnish obtained in Working Example 1-1 was coated onto an ITO substrate using a spin coater and was subsequently, in open air, pre-baked at 80 C. for 1 minute and then subjected to a main bake at 230 C. for 15 minutes, thereby forming a 40 nm thin film on the ITO substrate.

(36) Next, using a vapor deposition system (degree of vacuum, 4.010.sup.5 Pa), a thin film of aluminum was deposited thereon, giving a single-layer device. Vapor deposition was carried out at a deposition rate of 0.2 nm/s. The thickness of the aluminum thin film was set to 100 nm.

(37) To prevent the device characteristics from deteriorating due to the influence of oxygen, moisture and the like in air, the SLD was sealed with sealing substrates, following which the characteristics were evaluated. Sealing was carried out by the following procedure.

(38) The SLD was placed between sealing substrates in a nitrogen atmosphere having an oxygen concentration of 2 ppm or less and a dew point of not more than 85 C., and the sealing substrates were laminated together using an adhesive (MORESCO Moisture Cut WB90US(P), from Moresco Corporation). At this time, a desiccant (HD-071010W-40, from Dynic Corporation) was placed, together with the SLD, within the sealing substrates. The laminated sealing substrates were irradiated with UV light (wavelength, 365 nm; dosage, 6,000 mJ/cm.sup.2) and then annealed at 80 C. for 1 hour to cure the adhesive.

Working Examples 2-2 to 2-5

(39) Aside from using the varnishes obtained in Working Examples 1-2 to 1-5 instead of the varnish obtained in Working Example 1-1, SLDs were fabricated in the same way as in Working Example 2-1.

Comparative Example 2

(40) Aside from using the varnish obtained in Comparative Example 1 instead of the varnish obtained in Working Example 1-1, an SLD was fabricated in the same way as in Working Example 2-1. [4-2] Fabrication of Hole-Only Devices (HOD) and Evaluation of Device Characteristics

Working Example 3-1

(41) The varnish obtained in Working Example 1-1 was coated onto an ITO substrate using a spin coater and was subsequently, in open air, pre-baked at 80 C. for 1 minute and then subjected to a main bake at 230 C. for 15 minutes, thereby forming a 40 nm thin film (hole-injecting layer) on the ITO substrate.

(42) Next, using a vapor deposition system (degree of vacuum, 2.010 Pa), thin films of -NPD and aluminum were successively deposited thereon, giving a hole-only device. Vapor deposition was carried out at a deposition rate of 0.2 nm/s. The thicknesses of the -NPD and aluminum thin films were set to 20 nm and 100 nm, respectively.

(43) To prevent the device characteristics from deteriorating due to the influence of oxygen, moisture and the like in air, the HOD was sealed with sealing substrates, following which the characteristics were evaluated. Sealing was carried out in the same way as described above.

Working Examples 3-2 to 3-5

(44) Aside from using the varnishes obtained in Working Examples 1-2 to 1-5 instead of the varnish obtained in Working Example 1-1, HODs were fabricated in the same way as in Working Example 3-1.

Comparative Example 3

(45) Aside from using the varnish obtained in Comparative Example 1 instead of the varnish obtained in Working Example 1-1, an HOD was fabricated in the same way as in Working Example 3-1.

(46) The current densities at a driving voltage of 3 V were measured for the SLDs and HODs fabricated in the above Working Examples and Comparative Examples. The results are shown in Table 11. In addition, the relative strength of the HOD current density to the SLD current density at the same voltage is also shown. The fact that this relative strength is high indicates that the efficient supply of holes to the hole-transporting layer is being achieved.

(47) TABLE-US-00012 TABLE 11 Charge- Current density HOD/ transporting (mA/cm.sup.2) SLD varnish SLD HOD (%) Working Examples 2-1, 3-1 A 2,840 1,330 46.8 Working Examples 2-2, 3-2 B 2,890 1,250 43.3 Working Examples 2-3, 3-3 C 2,970 1,210 40.7 Working Examples 2-4, 3-4 D 2,590 1,120 43.2 Working Examples 2-5, 3-5 E 2,990 1,340 44.7 Comparative Examples 2, 3 F 2,530 879 34.7

(48) As shown in Table 11, devices that used a hole-injecting layer produced from a charge-transporting varnish of the invention, compared with devices fabricated in the Comparative Examples, all had high relative strengths of the HOD current density to the SLD current density. [4-3] Fabrication of Organic EL Devices and Evaluation of Device Characteristics

Working Example 4-1

(49) The varnish obtained in Working Example 1-1 was coated onto an ITO substrate using a spin coater and then dried at 80 C. for 1 minute and baked in an open-air atmosphere at 230 C. for 15 minutes, thereby forming a uniform 40-nm thin film (hole-injecting layer) on the ITO substrate.

(50) Using a vapor deposition system (degree of vacuum, 2.010.sup.5 Pa), a 20 nm film of -NPD was formed thereon at a deposition rate of 0.2 nm/s. CBP and Ir(PPy).sub.3 were then co-vapor deposited. Co-vapor deposition was carried out while controlling the vapor deposition rate so that the Ir(PPy).sub.3 concentration becomes 6%, thereby depositing a 40 nm layer. Next, thin-films of BAlq, lithium fluoride and aluminum were successively deposited, thereby giving an organic EL device. At this time, vapor deposition was carried out at a rate of 0.2 nm/s each for BAlq and aluminum, and at a rate of 0.02 nm/s for lithium fluoride. The thicknesses of the BAlq, lithium fluoride and aluminum thin films were set to respectively 20 nm, 0.5 nm and 100 nm.

(51) To prevent the device characteristics from deteriorating due to the influence of oxygen, moisture and the like in air, the organic EL device was sealed with sealing substrates, following which the characteristics were evaluated. Sealing was carried out in the same way as described above.

Working Example 4-2 to 4-5

(52) Aside from using the varnishes obtained in Working Examples 1-2 to 1-5 instead of the varnish obtained in Working Example 1-1, organic EL devices were fabricated in the same way as in Working Example 4-1.

Comparative Example 4

(53) Aside from using the varnish obtained in Comparative Example 1 instead of the varnish obtained in Working Example 1-1, an organic EL device was fabricated in the same way as in Working Example 4-1.

(54) The voltage, current density, current efficiency and half-life (initial brightness, 5,000 cd/m.sup.2) at a brightness of 5,000 cd/m.sup.2 were measured for these devices. The results are shown in Table 12. The size of the light-emitting surface on each device was set to a surface area of 2 mm2 mm.

(55) TABLE-US-00013 TABLE 12 Charge- Current Current Half- transporting Voltage density efficiency life varnish (V) (mA/cm.sup.2) (cd/A) (h) Working Example A 9.49 17.45 28.66 365 4-1 Working Example B 9.51 17.19 29.09 366 4-2 Working Example C 9.49 17.19 29.09 318 4-3 Working Example D 9.46 17.63 28.36 347 4-4 Working Example E 9.49 17.35 28.82 380 4-5 Comparative F 9.50 17.40 28.73 331 Example 4

(56) As shown in Table 12, compared with the organic EL device obtained in Comparative Example 4, all of the organic EL devices according to the invention had the same degree of driving voltages and current efficiencies, and had similar or better half-lives.