JP5549879B2 - Random copolymer - Google Patents

Description

  The present invention relates to a random copolymer having an arylamine structure and a method for producing the same, and is very useful as an organic semiconductor material such as an organic electroluminescence element (organic EL element), an organic transistor, and an organic thin film solar cell. is there.

  Many main chain arylamine polymers have been reported so far. Many of these polymers have a phenylene group in the side chain, and neither the description about the physical properties of the polymer in which the condensed ring is substituted with an amino group nor the synthesis method thereof are available (see, for example, Patent Documents 1 to 5). Recently, arylamine polymers in which side chains are substituted with fluoryl groups have been reported (see, for example, Patent Documents 6 to 7).

  In Patent Document 6, synthesis is performed using diboronic acid as a raw material in ethanol using a Suzuki-Miyaura coupling reaction, but there is no description regarding molecular weight. As a result of further testing, the weight average molecular weight was about 10,000 to 20,000. The cause is considered to be that when a condensed ring such as a fluorenyl group is substituted, an oligomer which is an intermediate is formed in the reaction process, and its solubility is low, so that a high molecular weight polymer is hardly formed. In patent document 7, although it synthesize | combines using the Yamamoto method which is dehalogenation polymerization, the weight average molecular weight described in the Example is about 3,000-4,000. Thus, in the conventional method, the molecular weight of the polymer in which a condensed ring such as a fluoronyl group is substituted on the side chain is extremely low. As a result, the stability of the organic thin film formed by the coating method is low. There was a problem of short.

Special table 2001-527102 US Pat. No. 5,728,801 JP 2004-292882 A JP 2003-316044 A JP 2002-80595 A JP 2009-43896 A Special table 2004-525501 gazette

  An object of the present invention is to provide a novel high-molecular-weight arylamine copolymer substituted with a fluorenyl group having a substituent at a specific position in a side chain, which has higher mobility and durability than conventional materials. . More specifically, it is to provide an arylamine random copolymer suitable for a hole injection material such as an organic EL device, a hole transport material and a light emitting material.

  As a result of intensive studies, the present inventors have heretofore reported an arylamine polymer having a specific monomer unit, in particular, a random copolymer of an arylamine containing a specific ratio in terms of efficiency and durability. It has been found that it is far superior to arylamine polymers and has led to the completion of the present invention. That is, this invention relates to the random copolymer which consists of a structural unit of the following general formula (1) and (2), and its manufacturing method.

(Wherein represents R ¹ to R ⁶ are each independently a linear or branched primary alkyl group or a phenyl group which may have a substituent having 1 to 18 carbon atoms. Note that R ¹ R ² , or R ⁴ and R ⁵ may be bonded to each other to form a ring, and Ar ¹ represents a group represented by the following general formulas (3) to (6).

(Wherein, A r ² represents a phenyl group or a fluorenyl group which may have a substituent.)

In the random copolymer comprising the structural units represented by the general formulas (1) and (2), R ^{1 to} R ⁶ are each independently a linear or branched primary alkyl group having 1 to 18 carbon atoms, or a substituent. Represents a phenyl group which may have

Examples of the alkyl group represented by R ^{1 to} R ⁶ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, an undecanyl group, a dodecanyl group, a tridecanyl group, Linear alkyl group such as tetradecanyl group, pentadecanyl group, hexadecanyl group, octadecanyl group, isopropyl group, 2-methylpropyl group, 2-methylbutyl group, 3-methylbutyl group, 2-ethylbutyl group, 4-methylpentyl group, Examples include branched alkyl groups such as 2-ethylhexyl group and 3,7-dimethyloctyl group.

  Examples of the phenyl group that may have a substituent include a phenyl group, a tolyl group, an anisidyl group, and a phenyl group substituted with a phenyl group.

R ¹ and R ² , or R ⁴ and R ⁵ may be bonded to each other to form a ring. Specific examples include the following spiro rings.

(In the formula, n represents an integer of 2 to 5, and R ²⁴ represents a linear or branched primary alkyl group having 1 to 18 carbon atoms, or a phenyl group which may have a substituent.)
In the general formula (2), Ar ¹ is a group represented by the following general formula (3).

(Wherein, A r ² represents a phenyl group or a fluorenyl group which may have a substituent.)

  The random copolymer of the present invention has organic thin film stability and high hole mobility, which are considered to be factors that improve durability and light emission efficiency in organic EL devices and the like. Among them, the ratio of the specific structural unit, specifically, the ratio of the structural unit of the general formula (2) to the sum of the structural unit of the general formula (1) and the structural unit of the general formula (2) (hereinafter referred to as the following) , F value) is 0.01 or more and 0.80 or less, and preferably 0.10 or more and less than 0.60, durability of the organic EL element can be brought about. Although the detailed factor which improves durability and luminous efficiency is unknown, it is probably because the structural unit represented by the general formula (2) is present as a partial crystal part in the random copolymer. This is probably because high mobility is provided, or when the random copolymer of the present invention is used, adhesion at the interface in contact with other thin film layers is improved.

Among the random copolymers of the present invention, more preferably, those having a structural unit represented by the general formula (3). More preferably, it is a random copolymer represented by the following general formulas ( 4 ) to ( 5 ).

^(Wherein, R 9 ^{to R 20} may be the table a linear or branched primary alkyl group having 1 to 18 carbon atoms each independently. In addition, ^{R 9} and ^{R 10,} or ^{R 12} and ^{R 13} are each They may combine to form a ring, and m and n are integers of 1 or more that satisfy 0.01 ≦ n / (n + m) (= the above F value) ≦ 0.80.
The weight average molecular weight of the random copolymer of the present invention is not particularly limited, but is in the range of 20,000 to 500,000 in terms of polystyrene, more preferably 40,000 to 100,000 in terms of polystyrene. Range.

  Next, the manufacturing method of the random copolymer of this invention is demonstrated.

The random copolymer of the present invention can be synthesized using the following general formulas ( 6 ), ( 7 ) and ( 8 ) as raw materials in the presence of a palladium catalyst and a base using a known Buchwald-Hartwig reaction ( See, for example, Palladium Reagents and Catalysts, John & Wiley).

(In the formula, X ¹ and X ² each represent a halogen atom, and R ^{21 to} R ²³ each independently represent a linear or branched primary alkyl group having 1 to 18 carbon atoms. Ar ¹ represents the following: It represents a group represented by formula (3).)

(Representing wherein, R ^7, R ⁸ are each independently a linear or branched primary alkyl group or a phenyl group which may have a substituent having 1 to 18 carbon atoms. In addition, with R ⁷ R ⁸ may bond to each other to form a ring, and Ar ^{2 to} Ar ⁴ represent a phenyl group or a fluorenyl group which may have a substituent.
The aminofluorene derivative represented by the general formula ( 8 ) as a raw material can be synthesized from the following fluorene derivative by a known method, for example. Specifically, a method via nitration / hydrogenation or a method via benzylamination / hydrogenation using bromination / Buchwald-Hartwig reaction can be mentioned.

  The random copolymer thus obtained has a halogen atom and / or amino group at the end of the random copolymer due to the charged monomer ratio of the compounds represented by the general formulas (11) to (13). A terminal protection treatment can be performed to stabilize the random copolymer.

  The random copolymer thus obtained can be subjected to a known reprecipitation method, inorganic oxides such as silica gel, alumina and activated clay, or treatment by column chromatography such as activated carbon and ion exchange resin as necessary. It can refine | purify by repeating.

  Moreover, the thin film which consists of a random copolymer of this invention can be formed by conventional methods, such as a spin coat method, a dip coat method, and a solvent cast method.

  The random copolymer composed of the structural units represented by the general formulas (1) and (2) according to the present invention is used as a p-type semiconductor material such as a hole injection material, a hole transport material, and an organic transistor of an organic EL device. It is very useful in terms of improving durability.

¹ H-NMR spectrum of 2-bromo-7-hexyl-9,9-dimethylfluorene is shown. ¹ H-NMR spectrum of 2-amino-7-hexyl-9,9-dimethylfluorene is shown. The ¹³ C-NMR spectrum of 2-amino-7-hexyl-9,9-dimethylfluorene is shown.

Hereinafter, the present invention will be described in more detail based on examples. In addition, the identification and purity of the compound obtained in the Example were performed by ¹ H-NMR measurement, ¹³ C-NMR measurement, GPC measurement, gas chromatography measurement, or liquid chromatography measurement.

[ ¹ H-NMR measurement, ¹³ C-NMR measurement]
Apparatus: Gemini200 manufactured by Varian
[Gas chromatography measurement]
Device: GC-17A manufactured by Shimadzu Corporation
Column: Capillary column (DB-5 manufactured by J & WScience)
Carrier gas: helium Column temperature: 150 ° C to 280 ° C (5 ° C / min)
Injection: 280 ° C
Detector: FID
[Liquid chromatography measurement]
Apparatus: Multi-station LC-8020 manufactured by Tosoh Corporation
Column: Inertsil ODS-3V (4.6 mmΦ × 250 mm)
Detector: UV detection (wavelength 254 nm)
Eluent: methanol / tetrahydrofuran = 9/1 (v / v ratio)
[GPC measurement]
Apparatus: HLC-8220
Column: G4000HXL-G3000HXL-G2000HXL-G2000HXL (both manufactured by Tosoh Corporation))
Detector: RI
Eluent: THF
Synthesis Example 1 (Synthesis of 2-bromo-7-hexyl-9,9-dimethylfluorene)
To a 2 L separable flask, 36.1 g (274 mmol) of anhydrous aluminum chloride and 1 L of dichloromethane were added, followed by stirring at room temperature until the aluminum chloride was dissolved. After confirming that the aluminum chloride was dissolved, 33.3 g (247.1 mmol) of hexanoyl chloride was added, and then a mixed solution consisting of 48 g (247.1 mmol) of 9,9-dimethylfluorene and 600 mL of dichloromethane was added at room temperature. Added dropwise for 2 hours. Then, after stirring for 4 hours, the reaction solution was dropped into an acidic aqueous solution consisting of 400 mL of 2N hydrochloric acid aqueous solution and 2 kg of ice to terminate the reaction. The reaction solution was transferred to a separatory funnel, and the organic phase was washed with water until the pH became neutral.

  The organic layer was concentrated to dryness to synthesize 70.6 g of 7-hexanol-9,9-dimethylfluorene (light brown powder, yield = 97.8%, gas chromatography purity = 98.0%). .

  Next, 65.5 g (224.2 mmol) of 7-hexanol-9,9-dimethylfluorene obtained, 25.5 g (385.7 mmol) of 85% potassium hydroxide, and 600 mL of ethylene glycol were added to a 1 L round bottom flask. . Next, after 36.1 g (721.5 mmol) of hydrazine monohydrate was added dropwise at room temperature, the mixture was refluxed at 220 ° C. for 6.5 hours. After cooling to room temperature, 500 mL each of toluene and water were added to extract the organic phase. The organic phase was washed until the pH became neutral, and then the organic phase was dried with magnesium sulfate. The oily substance obtained after the concentration was purified by silica gel chromatography (eluent: hexane) to obtain 58.0 g of 7-hexyl-9,9-dimethylfluorene as a light brown oily substance (yield = 93). 0.0%).

  Next, after adding 56.6 g (203.5 mmol) of 7-hexyl-9,9-dimethylfluorene and 500 mL of chloroform to a 1 L eggplant-shaped flask, 34.7 g (217 mmol) of bromine was added dropwise at room temperature. Stir for 3 hours. The reaction solution was washed successively with a saturated aqueous sodium carbonate solution, a 10% aqueous sodium thiosulfate solution, and water. The obtained organic phase was concentrated to obtain 2-bromo-7-hexyl-9,9-dimethylfluorene as a target product (yield = 98.0%).

It was confirmed by ¹ H-NMR measurement that it was the desired product (see FIG. 1).

Synthesis Example 2 (Synthesis of 2-amino-7-hexyl-9,9-dimethylfluorene)
To a 1 L eggplant-shaped flask, 35.9 g (100.6 mmol) of 2-bromo-7-hexyl-9,9-dimethylfluorene, 10.9 g (100.6 mmol) of benzylamine, 11.8 g of sodium tert-butoxide (120 .6 mmol) and 400 mL of xylene were added, and the reaction was bubbled with nitrogen for 20 minutes. Next, after adding a solution composed of 256 mg of tris (dibenzylideneacetone) dipalladium / chloroform complex (0.5 mmol in terms of palladium), 300 mg (1.4 mmol) of tri-tert-butylphosphine, and 10 mL of xylene to the reaction solution, The reaction was carried out at 120 ° C. for 5 hours. After the reaction solution was cooled to room temperature, 250 mL of water was added to extract the organic phase. The organic phase was concentrated and purified by silica gel chromatography to isolate 19.4 g of 2-benzylamino-7-hexyl-9,9-dimethylfluorene (yield = 50.3%, pale yellow rod-shaped crystal).

○ ¹ H-NMR of 2-benzylamino-7-hexyl-9,9-dimethylfluorene
¹ H-NMR (CDCl ₃ ) δ: 7.28-7.50 (7H, m), 7.16 (1H, brs), 7.09 (1H, dd, J = 8.0 Hz), 6.71 (1H, d, J = 2.2 Hz), 6.61 (1H, dd, J = 8.2, 2.2 Hz), 4.38 (2H, s), 4.4 (1H, brs), 2 .64 (2H, t), 1.2-1.8 (14H, m), 0.89 (3H, t)
Next, in a 50 mL eggplant type flask, 1.0 g of 2-benzylamino-7-hexyl-9,9-dimethylfluorene, 20 mL of toluene, 3.4 g of water and 10% palladium-carbon (made by N.E. Chemcat, PE Type) 0.16 g (dry base) was added, and the system was replaced with nitrogen. After raising the reaction temperature to 70 ° C., 0.6 g of formic acid was added dropwise, and the mixture was further heated and stirred at 90 ° C. for 6 hours. After cooling the reaction solution, the catalyst was filtered to separate the organic layer. By concentrating the obtained organic phase, 0.75 g of the objective 2-amino-7-hexyl-9,9-dimethylfluorene was isolated as colorless crystals (yield = 92%, HPLC purity = 98. 7%).

The target product was identified by ¹ H-NMR measurement and ¹³ C-NMR measurement (see FIGS. 2 and 3).

Synthesis Example 3 (Synthesis of 2-amino-7-pentyl-9,9-dimethylfluorene)
2-Bromo-7-pentyl-9,9-dimethylfluorene was synthesized according to Synthesis Example 1 except that hexanoyl chloride was changed to valeroyl chloride. Next, the target 2-amino-7-pentyl-9,9-dimethylfluorene was synthesized as colorless crystals according to Example 1.

Synthesis Example 4 (Synthesis of 2-amino-7-octanoyl-9,9-dimethylfluorene)
2-Bromo-7-octyl-9,9-dimethylfluorene was synthesized according to Synthesis Example 1 except that hexanoyl chloride was changed to octanoyl chloride. Next, the objective 2-amino-7-octyl-9,9-dimethylfluorene was synthesized as a colorless oil according to Example 1.

Synthesis Example 5 (Synthesis of N, N-di (4-bromophenyl) -2-amino-7-hexyl-9,9-dimethylfluorene)
Under a nitrogen atmosphere, in a 50 mL eggplant-shaped flask, 0.50 g (1.71 mmol) of 2-amino-7-hexyl-9,9-dimethyl-fluorene, 0.35 mL (3.40 mmol) of bromobenzene, sodium-tert-butoxide 0.39 g (4.06 mmol) and 10 mL of xylene were added. Next, a mixed solution consisting of 17.0 mg (0.016 mmol) of tris (dibenzylideneacetone) dipalladium / chloroform complex, 19 mg of tri-tert-butylphosphine and 5 mL of xylene was added and stirred at 120 ° C. for 3 hours. After cooling, 20 mL of pure water and 20 mL of toluene were added and then transferred to a separatory funnel to separate the organic layer. The organic layer was washed with saturated brine and then dried over magnesium sulfate. The organic layer was concentrated to obtain 0.88 g of a brown oil. Purification by silica gel chromatography gave 665.5 mg of a colorless viscous oil (yield = 87.7%). The ¹ H-NMR measurement and ¹³ C-NMR measurement results of the target product were as follows.

○ ¹ H-NMR measurement and ¹³ C-NMR measurement of 2-diphenylamino-7-hexyl-9,9-dimethylfluorene
¹ H-NMR (CDCl ₃ ) δ: 7.52 (2H, d, J = 7.6 Hz), 6.96-7.29 (14H, m), 2.66 (2H, t, J = 7. 6Hz), 1.61 (2H, m), 1.39 (6H, s), 1.32 (6H, br s), 0.89 (3H, t)
¹³ C-NMR (CDCl ₃ ) δ: 155.0, 153.7, 148.1, 146.8, 141.6, 136.5, 134.4, 129.2, 129.1, 128.2 127.1, 125.3, 123.9, 123.5, 122.5, 122.4, 120.2, 119.2, 118.9, 46.8, 36.4, 31.9, 29. 2, 27.3, 22.8, 14.3
Next, the obtained colorless viscous oil was dissolved in 7 mL of dimethylformamide, 2 mL of 544.9 mg (3.05 mmol) of N-bromosuccinamide in dimethylformamide was added, and the mixture was stirred at room temperature for 2 hours. Toluene and water were added to extract the organic layer. The brown oil obtained by concentrating the organic layer was purified by silica gel chromatography to obtain 818.5 mg of a colorless viscous oil (yield = 91.1%, HPLC purity = 98.1%). . The ¹ H-NMR measurement and ¹³ C-NMR measurement results of the target product were as follows.

○ ¹ H-NMR measurement and ¹³ C-NMR measurement of N, N-di (4-bromophenyl) -2-amino-7-hexyl-9,9-dimethylfluorene
¹ H-NMR (CDCl ₃ ) δ: 7.54 (2H, d, J = 7.8 Hz), 7.11-7.36 (7H, m), 6.97 (4H, d, J = 8. 8 Hz), 6.87 (1 H, d, J = 9.0 Hz), 2.67 (2 H, t, J = 7.6 Hz), 1.65 (2 H, m), 1.40 (6 H, s) , 1.33 (6H, br s), 0.89 (3H, t)
¹³ C-NMR (CDCl ₃ ) δ: 155.3, 153.7, 146.7, 125.7, 142.0, 136.2, 135.4, 132.3, 132.1, 129.1, 128.2, 127.3, 125.2, 123.8, 123.2, 122.6, 120.5, 119.3, 119.2, 115.2, 114.6, 46.9, 36. 4, 31.9, 29.2, 27.3, 22.8, 14.3
Reference example 1
In a 50 mL eggplant type flask under nitrogen atmosphere, 4,4′-diiodobiphenyl 1.62 g (4.0 mmol), 2,7-dibromo-9,9-dimethylfluorene 0.350 g (1.0 mmol), synthesis example 1.47 g (5.0 mmol) of 2-amino-7-hexyl-9,9-dimethylfluorene obtained in 2 above, 1.15 g (12 mmol) of sodium-tert-butoxide and 15 mL of xylene were added. Next, a mixed solution consisting of 25.8 mg (0.025 mmol) of tris (dibenzylideneacetone) dipalladium / chloroform complex, 29 mg of tri-tert-butylphosphine and 5 mL of xylene was added and stirred at 130 ° C. for 6 hours. Thereafter, 50 μL of bromobenzene was added and reacted for 2 hours, then 0.85 mL of a 10% xylene solution of diphenylamine was added, and the reaction was further performed for 2 hours. After completion of the reaction, the reaction mixture was cooled to about 80 ° C., and the reaction mixture was slowly added to 90% aqueous acetone (100 mL) with stirring. The solid was collected by filtration, washed in the order of acetone, water, and acetone, and dried under reduced pressure to obtain a pale yellow powder.

  Next, the obtained powder and 50 g of chlorobenzene were added to a 200 mL eggplant-shaped flask. After dissolving at 100 ° C., 4 g of basic alumina was added and stirred at the same temperature for 1 hour. After cooling, the mixture was heated and filtered at 80 ° C., and again the reaction mixture was slowly added to a 90% aqueous acetone solution (100 mL) with stirring. The solid was collected by filtration, washed in order of acetone, water and acetone, and dried under reduced pressure to obtain 1.91 g of a pale yellow powder (F value = 0.20, yield = 88%).

  The obtained polymer had a weight average molecular weight of 42,500 in terms of polystyrene and a dispersity (Mw / Mn) of 2.20.

Reference example 2
Reference Example 1 except that 2-amino-7-hexyl-9,9-dimethylfluorene was changed to 2-amino-7-pentyl-9,9-dimethylfluorene (5.0 mmol) obtained in Synthesis Example 3. According to the above, a polymer was synthesized.

  The obtained polymer had a weight average molecular weight of 57,400 and a dispersity (Mw / Mn) of 2.16 in terms of polystyrene.

Reference example 3
Reference Example 1 except that 2-amino-7-hexyl-9,9-dimethylfluorene was changed to 2-amino-7-octyl-9,9-dimethylfluorene (5.0 mmol) obtained in Synthesis Example 4. According to the above, a polymer was synthesized.

  The obtained polymer had a weight average molecular weight of 78,500 and a dispersity (Mw / Mn) of 2.41 in terms of polystyrene.

Reference Example 4 (Molar ratio change)
Using 4,4'-diiodobiphenyl 1.0 mmol, 2,7-dibromo-9,9-dimethylfluorene 4.0 mmol and 2-amino-7-hexyl-9,9-dimethylfluorene 5.0 mmol for reference 2.20 g of a polymer was synthesized according to Example 1 (F value = 0.80, yield = 93%). The obtained polymer had a weight average molecular weight of 84,800 and a dispersity (Mw / Mn) of 3.9 in terms of polystyrene.

Reference Example 5 (Molar ratio change)
Using 2.5 mmol of 4,4′-diiodobiphenyl and 2.5 mmol of 2,7-dibromo-9,9-dimethylfluorene, 2.05 g of a polymer was synthesized according to Reference Example 1 (F value = 0. 5, yield = 89%). The obtained polymer had a weight average molecular weight of 125,800 and a dispersity (Mw / Mn) of 4.1 in terms of polystyrene.

Example 1
In a 50 mL eggplant-shaped flask under nitrogen atmosphere, 2.17 g (5.36 mmol) of 4,4′-diiodobiphenyl, N, N-di (4-bromophenyl) -2-amino-7-hexyl-9,9 -Dimethylfluorene 805.5 mg (1.34 mmol), 2-amino-7-hexyl-9,9-dimethylfluorene obtained in Synthesis Example 2, 1.96 g (6.70 mmol), sodium tert-butoxide 1.54 g ( 16.0 mmol) and 22 mL of xylene were added. Next, a mixed solution consisting of 34.5 mg of tris (dibenzylideneacetone) dipalladium / chloroform complex, 40 mg of tri-tert-butylphosphine and 5 mL of xylene was added and stirred at 130 ° C. for 6 hours. Thereafter, 50 μL of bromobenzene was added and reacted for 2 hours, then 0.85 mL of a 10% xylene solution of diphenylamine was added, and the reaction was further performed for 2 hours. After completion of the reaction, the reaction mixture was cooled to about 80 ° C., and the reaction mixture was slowly added to 90% aqueous acetone (120 mL) with stirring. The solid was collected by filtration, washed in order of acetone, water and acetone, and then dried under reduced pressure to obtain 3.01 g of a pale yellow powder (F value = 0.20, yield = 90%).

  The obtained polymer had a weight average molecular weight of 108,000 in terms of polystyrene and a dispersity (Mw / Mn) of 3.4.

Reference Example 6
2,7 dibromo-9,9-dimethyl-fluorene 0.350 g (1.0 mmol), 2,7-dichloro -N- (4- (2- ethylhexyl) phenyl) was replaced by carbazole 1mmol the reference 2.12 g of polymer was synthesized according to Example 1 (F value = 0.20). The obtained polymer had a weight average molecular weight of 98,400 in terms of polystyrene and a dispersity (Mw / Mn) of 2.9.

Example 2 (Element fabrication)
A glass substrate having an ITO transparent electrode having a thickness of 130 nm was ultrasonically washed successively with acetone and isopropyl alcohol, then boiled and washed with isopropyl alcohol, and then dried. Furthermore, what was UV / ozone treated was used as a transparent conductive support substrate. On the ITO transparent electrode, a chlorobenzene solution containing 0.5% by weight of the random copolymer obtained in Example 1 was applied by spin coating (2000 rpm, 30 seconds) and dried at 150 ° C. in a vacuum oven. A hole injection layer was formed (film thickness = 20 nm). Further, 4,4′-di (1-naphthylaminophenyl) -1,1′-benzidine (hereinafter abbreviated as NPB) was formed to a film thickness of 45 nm by a vacuum deposition method to form a hole transport layer. . Next, an aluminum triskinolinol complex was formed into a film with a thickness of 60 nm by a vacuum vapor deposition method to form an electron transport layer. The organic compound was deposited under the same conditions of a vacuum degree of 1.0 × 10 ⁻⁴ Pa and a deposition rate of 0.3 nm / second.

  Next, LiF was deposited to 0.5 nm and Al was deposited to 100 nm as a cathode to form a metal electrode.

Further, a protective glass substrate was stacked in a nitrogen atmosphere and sealed with a UV curable resin. The device thus obtained was driven under a constant current density condition of 20 mA / cm ² with the ITO electrode as the positive electrode and the LiF-Al electrode as the negative electrode. Table 1 shows values of drive voltage, current efficiency, power efficiency, and luminance half-life at that time.

Comparative Example 1
Example 1 was repeated using 2.5 mmol of 4,4′-diiodobiphenyl and 5.0 mmol of 4,4′-diiodobiphenyl instead of 2.5 mmol of 2,7-dibromo-9,9-dimethylfluorene. Accordingly, 1.94 g of a homopolymer (compound A) having the following structure was synthesized (yield = 88%).

  The obtained polymer had a weight average molecular weight of 27,000 in terms of polystyrene and a dispersity (Mw / Mn) of 1.9.

Next, a device was fabricated using Compound A as a hole injection layer according to Example 8. The ITO electrode was used as a positive electrode and the LiF-Al electrode was used as a negative electrode, and the electrode was driven under a constant current density condition of 20 mA / cm ² . Table 1 shows values of drive voltage, current efficiency, power efficiency, and luminance half-life at that time.

Comparative Example 2
A device was produced using the following homopolymer (Compound B) (weight average molecular weight 26,200) instead of Compound A. The ITO electrode was used as a positive electrode and the LiF-Al electrode was used as a negative electrode, and the electrode was driven under a constant current density condition of 20 mA / cm ² . Table 1 shows values of drive voltage, current efficiency, power efficiency, and luminance half-life at that time.

Claims (9)

The random copolymer which consists of a structural unit of the following general formula (1) and (2).

(Wherein represents R ¹ to R ⁶ are each independently a linear or branched primary alkyl group or a phenyl group which may have a substituent having 1 to 18 carbon atoms. Note that R ¹ R ^2, or ^{R 4} and ^{R 5} may .Ar ¹ be bonded to each other to form a ring represents a group represented by the following general formula (3).)

(Wherein, A r ² represents a phenyl group or a fluorenyl group which may have a substituent.) Ar ¹ is said general formula (3) , The random copolymer of Claim 1 characterized by the above-mentioned. The ratio (F value) of the structural unit of the general formula (2) to the sum of the structural unit of the general formula (1) and the structural unit of the general formula (2) is 0.01 or more and 0.80 or less. The random copolymer according to claim 1 or 2. The random copolymer according to claim 3, wherein the F value is 0.10 or more and less than 0.60. The random copolymer according to claim 1, wherein Ar ^{2 in the} general formula ( 3 ) is a fluorenyl group having a substituent. A random copolymer represented by the following general formulas ( 4 ) to ( 5 ).

^(Wherein, R 9 ^{to R 20} may be the table a linear or branched primary alkyl group having 1 to 18 carbon atoms each independently. In addition, ^{R 9} and ^{R 10,} or ^{R 12} and ^{R 13} are each They may combine to form a ring, and m and n are integers of 1 or more that satisfy 0.01 ≦ n / (n + m) (= F value according to claim 3 ) ≦ 0.80. The random copolymer according to any one of claims 1 to 6, wherein the weight average molecular weight is in the range of 20,000 to 500,000 in terms of polystyrene. The random copolymer according to claim 7, wherein the weight average molecular weight is in the range of 40,000 to 100,000 in terms of polystyrene. The halogen compound represented by the following general formulas ( 6 ) and ( 7 ) and the amine compound represented by the general formula ( 8 ) are reacted in the presence of a palladium catalyst and a base. The manufacturing method of the random copolymer of description.

(In the formula, X ¹ and X ² each represent a halogen atom, and R ^{21 to} R ²³ each independently represent a linear or branched primary alkyl group having 1 to 18 carbon atoms. Ar ¹ represents the following: It represents a group represented by formula (3).)

(Wherein, A r ² represents a phenyl group or a fluorenyl group which may have a substituent.)

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