Platinum(II) complexes for OLED applications
The current invention relates to novel platinum(II) based organometallic materials. These materials show high emission quantum efficiencies and low self-quenching constant. Also provided are high efficiency, green to orange emitting organic light-emitting diode (OLED) that are fabricated using platinum(II) based organometallic materials as the light-emitting material. The organometallic materials of the invention are soluble in common solvents; therefore, solution process methods such as spin coating and printing can be used for device fabrication. The devices fabricated from these materials show low efficiency roll-off.
1. An organometallic complex having a chemical structure of Structure I:
wherein R 1 -R 15 are independently hydrogen, halogen, hydroxyl, an unsubstituted alkyl, a substituted alkyl, cycloalkyl, an unsubstituted aryl, a substituted aryl, acyl, alkoxy, acyloxy, amino, nitro, acylamino, aralkyl, cyano, carboxyl, thio, styryl, aminocarbonyl, carbamoyl, aryloxycarbonyl, phenoxycarbonyl, or an alkoxycarbonyl group;
wherein each pair of adjacent R groups of R 1 -R 15 can be independently two separate groups or one group, and form one or more 5-8 member rings with 2 or 4 X groups; and
wherein X 1 -X 20 are independently carbon, nitrogen, silicon, germanium, or phosphorous.
2. The organometallic complex of claim 1 , wherein R 11 is aryl or substituted aryl group, and R 10 can be one of the carbon atoms on R 11 thereby forming a 6-5-6 fused ring system with the adjacent aryl ring.
3. The organometallic complex of claim 1 , wherein each R 1 -R 15 is independently hydrogen, halogen, hydroxyl, an unsubstituted alkyl containing from 1 to 10 carbon atoms, a substituted alkyl containing from 1 to 20 carbon atoms, cycloalkyl containing from 4 to 20 carbon atoms, an unsubstituted aryl containing from 6 to 20 carbon atoms, a substituted aryl containing from 6 to 20 carbon atoms, acyl containing from 1 to 20 carbon atoms, alkoxy containing from 1 to 20 carbon atoms, acyloxy containing from 1 to 20 carbon atoms, amino, nitro, acylamino containing from 1 to 20 carbon atoms, aralkyl containing from 1 to 20 carbon atoms, cyano, carboxyl containing from 1 to 20 carbon atoms, thiol, styryl, aminocarbonyl containing from 1 to 20 carbon atoms, carbamoyl containing from 1 to 20 carbon atoms, aryloxycarbonyl containing from 1 to 20 carbon atoms, phenoxycarbonyl containing from 1 to 20 carbon atoms, or an alkoxycarbonyl group containing from 1 to 20 carbon atoms.
4. The organometallic complex of claim 1 , wherein the complex is not in planar geometry.
5. The organometallic complex of claim 1 , wherein the complex has a self-quenching constant that is no greater than the order of 10 −8 .
6. The organometallic complex of claim 1 , wherein the complex is selected from Complex 101 to Complex 131:
7. A method of preparing an organometallic complex of Structure I, comprising reacting a ligand compound of Structure II with a platinum(II) containing compound,
wherein said organometallic complex of Structure I is:
wherein said ligand compound of Structure II is:
wherein R 1 -R 15 of Structure I and Structure II are independently hydrogen, halogen, hydroxyl, an unsubstituted alkyl, a substituted alkyl, cycloalkyl, an unsubstituted aryl, a substituted aryl, acyl, alkoxy, acyloxy, amino, nitro, acylamino, aralkyl, cyano, carboxyl, thio, styryl, aminocarbonyl, carbamoyl, aryloxycarbonyl, phenoxycarbonyl, or an alkoxycarbonyl group;
wherein each pair of adjacent R groups of R 1 -R 15 of Structure I and Structure II can be independently two separate groups or one group, and form 5-8 member ring(s) with 2 or 4 X groups; and
wherein X 1 -X 20 of Structure I and Structure II are independently carbon, nitrogen, silicon, germanium, or phosphorous.
8. The method of claim 7 , wherein the platinum(II) containing compound is potassium tetrachloroplatinate.
9. The method of claim 7 , wherein the ligand compound of Structure II reacts with a platinum(II) containing compound in the presence of a solvent comprising acetic acid and chloroform.