WO2004026989A1 - Luminescent mixtures - Google Patents

Abstract

Disclosed are luminescent mixtures containing at least one organic polymer that is selected among the group comprising polyfluorene compounds (A), poly-(p-phenylene vinylene) compounds (B), poly(p-phenylene) compounds (C), and polythiophene compounds (D), and at least one heavy metal compound containing a heavy metal which has an atomic weight of at least 50 and is selected among the group comprising rows 1 through 3 of the transition metals, the metals of main groups 3, 4, and 5 of periods 5 and 6 of the periodic table, and the lanthanides, excluding platinum compounds, in case compounds of class (B) are selected while a heavy metal which has an atomic weight of at least 50 and is selected among the group comprising copper, zinc, and the metals of main groups 3, 4, and 5 of period 6 of the periodic table in case compounds of class (A), (C), and (D) are selected. Also disclosed is the use thereof for producing organic light emitting diodes.

Description

 Luminescent mixtures

Description 5

The present invention relates to new luminescent mixtures containing at least one organic polymer selected from the group consisting of polyfluorene compounds (A), poly (p-phenylene vinylene) compounds (B), poly (p-phenylene) compounds

10 (C) and polythiophene compounds (D), and at least one heavy metal compound containing, in the case of compound class (B), a heavy metal whose atomic weight is at least 50 and which is selected from the group consisting of the 1st to 3rd rows the transition metals, the metals of the 3rd, 4th and 5th main

15 group of the 5th and 6th period of the periodic table of the elements and the lanthanides, with the exception of platinum compounds, "and in the case of the compound classes (A), (C) and (D), a heavy metal whose atomic weight is at least 50 and that is selected from the group consisting of copper, zinc and

20 the metals of the 3rd, 4th and 5th main group of the 6th period of the periodic table of the elements, as well as their use for the production of organic light-emitting diodes (LED).

LEDs are well known and e.g. in Angew. Chem. 1998, 110, 25 416-443. They are applicable in many areas, e.g. in monochrome, multicolor or full-color screens (for example in applications in automobiles, mobile phones or notebooks).

30 From Adv. Mater., 1999, 11, 285-288, are mixtures of

Poly [4- (N-4-vinylbenzyloxyethyl, N-methylamino) -N- (2, 5-di-tert-butylphenylnaphthalimide)] with platinum-octaethylporphyrin and their use for the production of organic LEDs are known. However, it has been shown that the mixtures described there are still

35 have disadvantages, for example the relatively long life of the triplet emission of the platinum complex of 80 μs.

WO 01/96454 describes photoluminescent and electroluminescent compositions with an aromatic matrix and 40 luminescent metal ions or luminescent metal complexes.

The object of the present invention was to provide new mixtures which are advantageously suitable for the production of organic LEDs. 45 Accordingly, the mixtures identified at the outset were found.

The luminescent mixtures according to the invention contain at least one organic, preferably electroluminescent, organic polymer selected from the group consisting of polyfluorene compounds (A), poly (p-phenylene vinylene) compounds (B), poly (p-phenylene) compounds (C) and Polythiophene compounds (D).

The organic polymers contained in the mixtures according to the invention generally have an average molecular weight of 10 ³ to 10 ⁷ g / mol, based on polystyrene standards, determined by gel permeation chromatography.

They preferably contain the structural elements of the formulas I to IV:

Fluorene elements of formula I.

worin

wherein

Ar ^ic ₆ -C ₂ o-arylene, preferably Cβ-Cio-arylene, CC ₂ o ^_ heteroarylene, preferably C ₄ -Cιn-heteroarylene, or a divalent radical of a triarylamine having 18 to 60, preferably 18 to 30 carbon atoms, which is linked via carbon-carbon bonds.

R ¹ and R ² are each independently of one another C ¹ -C ₃ -alkyl, which can be interrupted by one or more oxygen or sulfur atoms or by one or more imino or C 1 -C ₄ -alkylimino groups, or C ₂ -Ci ₃ -Alko y, and

m and n each represent 0 to 1, with the proviso that the sum of m and n is 1; p-Phenylene vinylene elements of the formula II

worin

wherein

A ¹ and A ² are each independently hydrogen or cyano,

Ar ² Cg-C ₂ o ~ ar len, preferably C _Ö -C _IO arylene, C ₄ -C ₂ o heteroarylene, preferably C ₄ -Cιo heteroarylene, or a divalent radical of a triarylamine with 18 to 60, preferably 18 to 30 carbon atoms which are linked via carbon-carbon bonds,

R ³ and R ⁴ are each independently of one another C 1 -C ₃ -alkyl, which can be interrupted by one or more oxygen or sulfur atoms or by one or more imino or C 1 -C ₄ -alkylimino groups, Cχ-Ci ₃ -alkoxy , i-Cig-Acyl or Tri (C-Cχ ₆ -alkyl) siloxy, and

p and g each represent 0 to 1, with the proviso that the sum of p and q is 1;

p-phenylene elements of formula III

R5

worin

wherein

Ar ³ Cg-C ₂ o-arylene, preferably C _ß -Cio-arylene, C ₄ -C ₂ o-heteroarylene, preferably C ₄ -Cιo-heteroarylene or a divalent radical of a triarylamine with 18 to 60, preferably 18 to 30 carbon atoms linked by carbon-carbon bonds, R ⁵ and R ⁶ are each independently of one another C 1 -C ₃ -alkyl which can be interrupted by one or more oxygen or sulfur atoms or by one or more imino or C 1 -C ₄ -alkylimino groups, C 1 -C ₃ - Alkoxy, C ₄ -C ₆ -acyl or tri (Cj-Ci _ß- alkyl) siloxy, and

r and s each represent 0 to 1, with the proviso that the sum of r and s is 1; and

Thiophene elements of the formula IV

worin

wherein

Ar ^{4 is} C ₆ -C ₂₀ ^-A ylene, preferably C _ö -Cio-arylene, CC ₂ o-heteroarylene, C ₄ -Cχo heteroarylene, or a divalent radical of a triarylamine preferably 18 to 60, preferably 18 to 30 Carbon atoms linked by carbon-carbon bonds,

R ⁷ and R ⁸ are each independently of the other Cχ-Ci ₃ alkyl, which can be interrupted by one or more oxygen or sulfur atoms or by one or more imino or C 1 -C ₄ alkylimino groups, C 1 -C ₃ alkoxy , C-Cχ ₆ -acyl or tri (C ₄ -Cχ ₆ -alkyl) siloxy, and

t and u ^' each represent 0 to 1, with the proviso that the sum of t and u is 1.

Organic polymers of the formulas I to IV with the structural elements mentioned above are known per se and are e.g. in Adv. Mater., 2000, 12, 1737-1750, Angew. Chem., 1998, 110, 416-443, Adv. Mater., 1999, 11, 241-246, US-A-5 777 070, EP-A-1 134 269 and Nature, 1999, 397, 121-128, described.

Important organic polymers are, for example, polyfluorene compounds (A) which have structural elements of the formula I, poly (p-phenylene vinylene) compounds (B) which have structural elements of the formula II, poly (p-phenylene) compounds (C), the structural elements of Have formula III, and polythiophene compounds (D) which have structural elements of formula IV. The polymers of the formula I, II, III and IV can be both homopolymers and copolymers.

Organic polymers which are selected from the group consisting of polyfluorene compounds (A), in particular those which have structural elements of the formula I, and poly- (p-phenylene vinylene) compounds (B), in particular those which have structural elements of the formula II, are preferred have, with poly (p-phenylene-vinylene) compounds (B), in particular those which have structural elements of the formula II, to be particularly emphasized.

Organic polymers which may be mentioned are, in particular, homopolymers which have structural elements of the formula I in which R ¹ and R ^{2 are} each, independently of one another, C ¹ -C 6 -alkyl, in particular butyl, hexyl or 2-ethylhexyl, and the copolymers analogous thereto Formula I in which Ar ^{1 is} a divalent radical of a triphenylamine, a thiophene or a carbazole, and homopolymers of the formula II in which R ³ and R ^{4 in} each case Ci-Cs-alkoxy, in particular methoxy and 2-ethylhexyloxy, or Tri (Ci-Cs-alkyl) - silyl mean, as well as the copolymers of analog

Formula II in which Ar ^{2 is} a divalent residue of a triphenylamine, a thiophene or a carbazole.

The organic polymers used generally have an electrical conductivity of at least 10 ^{~ 9} S / cm, preferably at least 10 ^{~ 7} S / cm and in particular at least 10 ^{~ 6} S / cm.

The luminescent mixtures according to the invention can also have mixtures of the organic polymers described in more detail above with one another.

The organic polymers contained in the luminescent mixtures according to the invention are generally compounds known per se, such as those e.g. in Adv. Mater, 2000, 12, 1737, and Angew. Chem., 1998, 110, 416-443.

The luminescent mixtures according to the invention further contain at least one heavy metal compound with a heavy metal whose atomic weight is at least 50, preferably at least 63.

In the case of the compound class (B), the heavy metal is selected from the group consisting of the 1st to 3rd row of transition metals, the metals of the 3rd, 4th and 5th main group of the 5th and 6th period of the periodic table Elements and the lanthanides, with the exception of platinum compounds. In the case of the compound classes (A), (C) and (D), the heavy metal is selected from the group consisting of copper, zinc and the metals of the 3rd, 4th and 5th main group of the 6th period of the Periodic Table of the Elements.

In the case of compound class (B), preferred heavy metals are those selected from the group consisting of the lanthanides, copper, rhenium, osmium, iridium, gold, thallium, lead and bismuth, with europium, terbium, copper, rhenium, iridium , Gold, lead and bismuth are particularly noteworthy.

In the case of the compound classes (A), (C) and (D), preferred heavy metals are those which are selected from the group consisting of copper, zinc, thallium, lead and bismuth, copper, lead and bismuth being particularly mentioned.

Organic heavy metal complexes are to be mentioned in particular as heavy metal compounds.

Complexing agents for such heavy metal complexes are preferably derived from compounds which are selected from the group consisting of 2, 2 '-bipyridyl, 1, 10-phenanthroline, 2-pyridinecarboxylate (pic), 2-carbaldehydimino-phenolate (sal) and from 1,3-dicarbonyl compounds, especially those of formula V

worin

wherein

T ¹ , T ² and T ³ are each independently of one another C 1 -C ₃ -alkyl,

C ₆ -Ci ₂ - ryl or C ₄ -Cιo heteroaryl or in each case T ¹ and T ² or T ² and T ³ _' together with the carbon atoms to which they are attached, a 5- to 7-membered saturated or unsaturated carbocycle or Heterocycle mean.

Other complexing agents are selected from the group consisting of 2-phenylpyridine (ppy), 2- (4-tolyl) pyridine (tpy), 1-phenanthridine (bzq), 2- (2-thienyl) pyridine (thp), 2- (2-benzo [b] thiophenyl) pyridine (btp), 2, 5-diphenyloxazole (dpo), 2- (2-oxo-7-diethylamino-3-benzo [b] pyranyl) benzothiazole (C6) , 2-phenylbenzoxazole (bo), 2-phenylbenzthiazole (bt), 2- (l-naphthyl) benzoxazole (bon), 2-phenyl-4,5-dihydrooxazole (op), 2- (l-naphthyl) benzothiazole (αbsn), 2- (2-naphthyl) benzthiazole (ßbsn), 2- (2-thienyl) benzothiazole (btth) and 2-phenylquinoline (pq).

^" Other possible metal complexes are those of the formulas VI to XVIII:

(VI)

(VII) (VIII)

(XII) (XIII)

(Xv)

(XIV)

(XVI) (XVII)

(XVIII) wherein

E ⁱ to E ⁸ each independently of one another are hydrogen, C ₁ -C ₃ -alkyl, C ₆ -Ci ₂ -aryl or C ₄ ~ -CC-heteroaryl,

E ⁹ and Ei ° independently of one another are each C ₁ -C ₃ alkyl, C ₆ -C ₂ aryl, C ₄ -C 4o heteroaryl, Cx-Cis-alkoxy, halogen, cyano or thiocyanato,

EU and _E i2 independently of one another each C ₁ -C ₃ -alkyl, C ₆ -Ci ₂ ~ aryl or C ₄ -Cχo-heteroaryl,

E ^x3 , E ^X4 and E ^X5 independently of one another are each C 1 -C ₃ -alkyl,

C ₆ -Ci ₂ aryl or C ₄ -Cχo heteroaryl or in each case E ⁱ³ and E ⁱ⁴ or E ¹⁴ and E ⁱ⁵ , together with the carbon atoms to which they are attached, a 5- to 7-membered saturated or unsaturated

Carbocycle or heterocycle,

L ^{l is} a bidentate ligand, in particular 2,2'-bipyridy1 or 1,10-phenanthro1in,

2-phenylpyridine or 2-phenybenzoxazole,

M is a heavy metal defined in more detail above,

M ^l Europium or Terbium,

X and Y each independently of one another oxygen, sulfur imino, -CC-alkylimino or C ₆ -C ₁₂ arylamino,

Z nitrogen or phosphorus and

w is 1 to 3. Such complex ligands and metal complexes are known per se and, for example, in J. Am. Chem. Soc. 123, 2001, 4304-4312, Inorg. Che. 40, 2001, 1704-1712, Adv. Mater. 2000, 12, 1591-1594, Adv. Mater. 2001, 13, 1245, WO 99/53724, WO 00/57676, WO 01/08230, WO 01/39234 and WO 01/41512.

All alkyl radicals contained in the formulas listed here can be both straight-chain and branched.

Examples of alkyl radicals are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, 2-methylpentyl, heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl , Isononyl, decyl, isodecyl, undecyl, dodecyl, tridecyl or isotridecyl. (The above designations isooctyl, isononyl, isodecyl and isotridecyl are trivial names derived from the alcohols obtained by oxo synthesis -. Cf. Ullmann's Encyclopedia of Industrial Chemistry, ^5th Edition, Vol A1, pp 290-293, and Vol.. A 10, pages 284 and 285.)

Alkyl radicals which are interrupted by one or more oxygen or sulfur atoms or by one or more imino or C 1 -C ₄ -alkylimino groups are, for example, 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 2-butoxyethyl, 2- or 3-methoxypropyl, 2- or 3-ethoxypropyl, 2- or 3-propoxypropyl, 2- or 4-methoxybutyl, 2- or 4-ethoxybutyl, 3, 6-dioxaheptyl, 3, 6-dioxaoctyl, 3, 7-dioxaoctyl , 4, 7-dioxaoctyl, 2- or 3-butoxypropyl or 2- or 4-butoxybutyl or the corresponding radicals which have sulfur atoms, imino or, for example, methyl or ethylimino groups instead of the oxygen atoms.

Alkoxy residues are e.g. Methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy tert-butyl, pentyloxy, isopentyloxy, neopentyloxy, tert-pentyloxy, hexyloxy, 2-methyloxypentyloxy, heptyloxy, octyloxy, 2-ethyloxyhexyloxy, isooctyloxy, nonyl - oxy, isononyloxy, decyloxy, isodecyloxy, ündecyloxy, dodecyloxy, tridecyloxy or isotridecyloxy.

Aryl residues are e.g. Phenyl, 2-, 3- or 4-methylphenyl, 2-, 3- or 4-ethylphenyl, 2, 4-dimethylphenyl, naphthyl or 2-methylnaphthyl.

Arylene residues are e.g. Phenylene, 2-, 3- or 4-methylphenylene, 2-, 3- or 4-ethylphenylene, 2,4-dimethylphenylene, naphthylene or 2-methylnaphthylene. Heteroaryl or heteroarylene residues are derived, for example, from the following heterocycles: pyrrole, furan, thiophene, pyridine, pyrimidine, triazine, indole, benzofuran, benzoxazole, benzothiazole, quinoline or isoquinoline.

Acyl residues are e.g. Butanoyl, isobutanoyl, sec-butanoyl, pentanoyl, isopentanoyl, neopentanoyl, hexanoyl, 2-methylpentanoyl, heptanoyl, octanoyl, 2-ethylhexanoyl, isooctanoyl, nonanoyl, isononanoyl, decanoyoyl, decanoyoyl, decanoyoyl Pentadecanoyl or Hexadecanoyl.

The ligands 2, 2 '-bipyridyl, 1, 10-phenanthroline, 2-phenylpyridine, 2-phenylbenzoxazole (bo) and 1,3-dicarbonyl compounds, in particular those of the formula V, are of particular importance.

The luminescent mixtures according to the invention can also have mixtures of the heavy metal compounds specified above.

Preferred are luminescent mixtures comprising at least one heavy metal complex with a heavy metal defined in more detail above and a complexing agent which is derived from an organic compound selected from the group consisting of 2,2'-bipyridyl, 1, 10-phenanthroline, 2- phenylpyridine,

2-phenylbenzoxazole (bo) and ligands of the formula V.

Other ingredients that may be contained in the luminescent mixtures according to the invention are e.g. B. dopants, such as fluorescent dyes, for example the dyes of the formulas XIX and XX mentioned below.

XIX XX

The proportion of organic polymers in the luminescent mixtures according to the invention is generally 70 to 99.999% by weight, preferably 85 to 99.99% by weight and especially 95 to ^'99.9 wt .-%, each based on the total weight of the mixture.

The proportion of the heavy metal compounds in the luminescent mixtures according to the invention is generally 0.01 to 30% by weight, preferably 0.1 to 20% by weight and in particular 0.5 to 15% by weight, in each case based on the total weight of the mixture.

The proportion of the above-mentioned further constituents in the luminescent mixtures according to the invention is generally 0 to 5.0% by weight, preferably 0 to 2.0% by weight, in each case based on the total weight of the mixture.

The luminescent mixtures according to the invention can be obtained in a manner known per se. For example, by customary mixing of the organic polymers with the heavy metal complexes and, if appropriate, with the further constituents described in more detail above.

The mixtures according to the invention, containing at least one organic polymer and at least one heavy metal complex, are luent. This means that after energetic stimulation e.g. to emit light through light and electricity.

Another object of the present invention is the use of the luminescent mixtures according to the invention as organic LEDs.

Organic LEDs are generally constructed in such a way that an organic electroluminescent layer containing a thickness of 20 to 200 nm is located between an anode and a cathode. The mixture according to the invention is preferably located between the two electrodes. The mixture according to the invention is particularly preferably located between a hole-transporting layer and an electron-transporting layer.

Claims

claims 1. Luminescent mixtures containing at least one organic polymer selected from the group consisting of polyfluorene compounds (A), poly - (p-phenylene vinylene) compounds (B), poly (p-phenylene) compounds (C) and polythiophene compounds ( D), and at least one heavy metal compound containing, in the case of compound class (B), a heavy metal whose atomic weight is at least 50 and which is selected from the group consisting of the 1st to 3rd row of transition metals, the metals of the 3rd ., 4th and 5th main group of the 5th and 6th period of the Periodic Table of the Elements and the lanthanides, with the exception of platinum compounds, and in the case of the compound classes (A), (C) and (D), a heavy metal, its atomic weight is at least 50 and is selected from ^" the group consisting of copper, zinc and the metals of the 3rd, 4th and 5th main group of the 6th period of the Periodic Table of the Elements. Luminescent mixtures according to claim 1, characterized in that they contain at least one heavy metal compound containing a heavy metal, the atomic weight of which is at least 63. 3. Luminescent mixtures according to claim 1, characterized in that they contain at least one heavy metal complex, the complexing agent being composed of organic compounds selected from the group consisting of 2,2'-bipyridyl, 1,10-phenanthroli, 2- Phenylpyridi, 2-phenylbenzoxazole (bo) and 1, 3-dicarbonyl compounds. 4. Luminescent mixtures according to claim 1, marked thereby characterized, that they, in each case based on the total weight of ^'the mixture, 95 to 99.9 wt .-% of at least one organic polymer and 0.01 to 30 wt .-% of at least one Heavy metal compound included. 5. Use of the luminescent mixtures according to claim 1 for the production of organic light-emitting diodes.