Electroluminescent device including gallium complexes
View Patent ↗An OLED device comprises an anode, a light emitting layer, a first layer, a second layer contiguous to the first layer, and a cathode, in that order. The first layer includes a first complex comprising gallium and the second layer includes a second complex also comprising gallium and wherein the second complex has a more negative LUMO than the first complex. Such materials can provide an improvement in one or more of luminance, drive voltage, and stability.
1. An OLED device comprising an anode, a light emitting layer, only one first layer, only one second layer contiguous to the first layer, and a cathode, in that order, and wherein the first layer includes a first complex comprising gallium and the second layer includes a second complex also comprising gallium and wherein the second complex has a more negative LUMO than the first complex; wherein the first complex is represented by Formula (3a) and the second complex is represented by Formula (3b):
wherein:
each r 1 may be the same or different and each represents a substituent and n is 0-2;
each r 2 , r 3 , and r 4 may be the same or different and each represents a substituent, provided adjacent substituents may combine to form a ring group and m, p, and q are independently 0-4.
2. The device of claim 1 wherein the difference in the LUMO value of the first and second complexes is 0.1 eV or greater.
3. The device of claim 1 wherein the difference in the LUMO value of the first and second complexes is 0.2 eV or greater.
4. The device of claim 1 wherein the first layer is contiguous to a light-emitting layer.
5. The device of claim 1 wherein the light-emitting layer includes a host material, and wherein the host material has a LUMO value that is more negative than the LUMO value of the first complex.
6. The device of claim 1 wherein the light-emitting layer includes a host material, and wherein the difference in LUMO values between the host material and the first complex is 0.1 eV or less.
7. The device of claim 1 wherein the second layer is contiguous to an electron-injecting layer.
8. The device of claim 1 wherein the second layer comprises an alkali metal material.
9. The device of claim 8 wherein the alkali metal material comprises lithium.
10. The device of claim 1 wherein the light-emitting layer includes a material that emits blue or blue-green light.
11. The device of claim 1 wherein the light-emitting layer includes a host material that comprises an anthracene group.
12. The device of claim 1 wherein the light-emitting layer includes a host material that comprises an anthracene group bearing independently selected aromatic substituents in the 2-, 9-, and 10-positions.