Light-emitting materials for light-emitting diodes

Abstract

The present invention relates to light-emitting materials for light-emitting diodes. The structure for the light-emitting materials is shown in Formula I. The platinum (II) complexes of the present invention show high emission quantum efficiency, good thermal stability and low quenching constant, thus can be used for producing red light OLED with high efficiency and low efficiency attenuation. ##STR00001##

Claims

1. A light-emitting material for light-emitting diode, wherein its structure is shown as formula I, ##STR00010## Wherein, R.sub.1-R.sub.26 are independently hydrogen, halogen, hydroxy, unsubstituted alkyl, cycloalkyl, unsubstituted aryl, alkoxy, acyloxy, amino, nitro, acylamino, aralkyl, cyano, carboxyl, styryl, aminocarbonyl, carbamoyl, aryloxycarbonyl, phenoxycarbonyl or alkoxycarbonyl, and R.sub.1-R.sub.26 can independently form a 5- to 8-membered ring with other adjacent R.sub.1-R.sub.26 groups.

2. The light-emitting material according to claim 1, wherein R.sub.1-R.sub.26 are independently hydrogen, halogen, hydroxy, C1-C6 alkyl, five- or six-membered cycloalkyl, five- or six-membered aryl, alkoxy, amino, nitro, cyano, and carboxyl, and R.sub.1-R.sub.26 may independently form a five- or six-membered ring with other adjacent R.sub.1-R.sub.26 groups.

3. The light-emitting material according to claim 2, wherein R.sub.3-8 and R.sub.17-22 are independently hydrogen.

4. The light-emitting material according to claim 3, wherein R.sub.1, R.sub.11, R.sub.16, R.sub.24 are independently hydrogen, R.sub.2, R.sub.23, R.sub.9-10, R.sub.25-26 are independently hydrogen, C.sub.1-C.sub.6 are alkyl.

5. The light-emitting material according to claim 4, wherein R.sub.12-15 are independently hydrogen, halogen, hydroxy, C.sub.1-C.sub.6 alkyl, 5-membered or 6-membered cycloalkyl, 5-membered or 6-membered aryl, amino, nitro, cyano, or 5-membered or 6-membered aromatic rings formed by R.sub.13 and R.sub.14.

6. The light-emitting material according to claim 5, wherein R.sub.13 and R.sub.14 are independently hydrogen, halogen, C.sub.1-C.sub.4 alkyl, amino, nitro, cyano, or a benzene ring formed by R.sub.13 and R.sub.14.

7. The light-emitting material according to claim 6, wherein R.sub.12 and R.sub.15 are independently hydrogen, C.sub.1-C.sub.6 alkyl.

8. The light-emitting material according to claim 7, wherein it is the compound having the following structures: ##STR00011## ##STR00012## ##STR00013## ##STR00014## ##STR00015## ##STR00016##

9. An organic light-emitting device containing one or more light-emitting materials for a light-emitting diode as described in claim 1.

10. The OLED according to claim 9, wherein the light-emitting material for light-emitting diodes is applied in layers in the device by thermal deposition; or the light-emitting material for light-emitting diodes is applied in layers in the device by spin coating; or the light-emitting material for light-emitting diodes is applied in layers in the device by ink jet printing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1: a scheme for the synthesis of ligands having a chemical structure of Structure II,

(2) FIG. 2: a scheme for the synthesis of a complex having a chemical structure of structure I,

(3) FIG. 3: Absorption and emission spectra of complex 101,

(4) FIG. 4: Cyclic voltammetry of complex 101,

(5) FIG. 5: Data of an OLED prepared with complex 101,

(6) FIG. 6: Spectra of an OLED prepared with complex 101.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

(7) The following are embodiments of the preparation, physical properties, and electroluminescent data of platinum (II) complexes (light-emitting materials for light-emitting diodes). The embodiments are presented to help the understanding of the invention, which are not intended and should not be construed as limiting the invention as claimed in claims appended thereof in any way.

(8) Unless otherwise indicated in the following embodiments, descriptions and claims, all parts and percentages are calculated by weight, and all temperatures are in degrees Celsius, and the pressure is the atmospheric pressure or close to atmospheric pressure.

(9) All digitals, values and/or expressions of the ingredients, reaction conditions used in the descriptions and claims that are not used in embodiments or as otherwise indicated should be construed to be defined as about in all instances.

(10) Any drawing or numerical range of a technical feature can be combined with drawings or parameters at different ranges with the same technical features, to form a numerical range.

Embodiment 201General Method for Preparing a Ligand Having the Chemical Structure of Structure II

(11) Referring to FIG. 1, the chemical structure having structure II is obtained by condensation of two imine bonds with a chemical containing o-phenylenediamine group (structure III) and a chemical compound containing phenol and double rings (structure IV). (The above structures III and IV are commercially available).

Embodiment 202Preparation of Ligand 301

(12) ##STR00008##

(13) The ligand 301 is prepared by the method in Embodiment 201, wherein R.sub.1-R.sub.26 are hydrogen. Yield: 100%. .sup.1H NMR (500 MHz, CDCl.sub.3) 13.33 (s, 2H), 8.54 (s, 2H), 7.34-7.22 (m, 2H), 7.22-7.11 (m, 2H), 7.09 (s, 2H), 6.87 (s, 2H), 3.32 (d, J=11.0 Hz, 4H), 1.90 (d, J=7.5 Hz, 4H), 1.73 (d, J=8.1 Hz, 2H), 1.54 (d, J=8.6 Hz, 2H), 1.20 (d, J=5.7 Hz, 4H).

Embodiment 203the General Method for Preparing a Complex Having the Structure I

(14) Referring to FIG. 2, firstly dissolve the ligand having the chemical structure of structure II (301) and twice of weak base in a small amount of hot dimethylformamide, then add platinum solution of methylsulfoxide, after reaction overnight, collect the precipitate by filtration, and then purify by recrystallization.

Embodiment 204Preparation of Complex 101

(15) ##STR00009##
Prepare complex 101 according to the method in the Embodiment 203, of which, the weak base is sodium acetate and the platinum salt is potassium tetrachloroplatinate, with a yield of 32%. .sup.1H NMR (500 MHz, CD.sub.2Cl.sub.2) 8.76 (s, 2H), 7.97 (dd, J=6.0, 3.2 Hz, 2H), 7.32 (dd, J=6.1, 3.2 Hz, 2H), 7.28 (s, 2H), 7.08 (s, 2H), 3.36 (d, J=6.4 Hz, 4H), 1.97 (d, J=8.3 Hz, 4H), 1.80 (d, J=8.0 Hz, 2H), 1.62 (d, J=8.8 Hz, 2H), 1.31 (d, J=7.5 Hz, 4H).

Embodiment 205Photophysical Properties of Complex 101

(16) TABLE-US-00001 .sub.abs [nm] .sub.em k.sub.q ([dm.sup.3mol.sup.1cm.sup.1]) [nm] [s] [10.sup.8 dm.sup.3mol.sup.1 s.sup.1] .sub.em 262 (27300), 319 (14200), 624 6.3 0.1 0.20 368 (28500), 386 (32000), 465 (10500), 534 (7200)

Embodiment 206Electrophysical Properties of Complex 10

(17) TABLE-US-00002 HOMO [eV] LUMO [eV] E.sub.g [eV] 5.15 2.89 2.26

Embodiment 207General Method for Preparing OLED by Thermal Dissociation

(18) In a high vacuum environment (pressure <110.sup.6 torr), deposition is performed sequentially over the transparent material, the hole transporting layer, the electron-transporting layer, the anode and the metal cathode of the electron injection layer.

Embodiment 208

(19) a device made according to Embodiment 207, wherein, the hole transporting layer is 4,4-cyclohexylbis [N,N-bis(4-methylphenyl)aniline] (TAPC); The light-emitting layer consists of two distinct layers. The first layer is mainly a light-emitting layer of tris (4-carbazol-9-yl)-amine (TcTa) (host material) doped with a small amount of complex 101 (dopant), and the second layer is a light-emitting layer mainly composed of 9,9-(2,6-pyridinediylbis-3,1-phenylene) bis-9H-carbazole (host material), doped with a small complex 101 (dopant); the electron-transporting layer is a 40 nm 3,3-[5-[3-(3-pyridyl) phenyl] [1,1:3,1-terphenyl]-3,3-diyl]bipyridine (TmPYPB); and the electron injection layer is 1 nm lithium fluoride and the metal cathode is 100 nm aluminum.

Embodiment 209

(20) Embodiment 209 illustrates the performance of OLED device using complex 101 as a light-emitting material according to the method described in Embodiment 208

(21) TABLE-US-00003 Doping V.sub.tum-on B.sup.a) .sub.c max.sup.b) .sub.p.sup.c) .sub.c 1000(cdA.sup.1).sup.d) .sub.croll-off at ratio (V) (cdm.sup.2) (cdA.sup.1) (lmW.sup.1) (1000 cdm.sup.2) 1000 cdm.sup.2 .sup.e) 2% 3.5 6712 7.75 6.35 5.28 32% 3% 3.5 9512 9.92 7.83 6.79 32% 4% 3.7 10810 10.82 9.00 7.02 35% 5% 3.5 9834 8.27 5.81 5.83 30% 6% 3.5 7424 8.72 7.20 5.90 32% 7% 3.5 6414 5.77 5.18 3.32 42% .sup.a)maximum brightness; .sup.b)maximum current efficiency; .sup.c)maximum power supply efficiency; .sup.d)current efficiency at 1000 cdm.sup.2; .sup.e) efficiency attenuation = 1 (.sub.c 1000/.sub.c max)