A Novel Organic Light-Emitting Device with Reduced Optical Losses at the Cathode

Abstract:
Stimulated emission in electrically pumped organic devices has not been demonstrated so far. It requires minimization of various losses, a.o. singlet-polaron quenching, quenching of singlets at contacts, and light absorption at metallic contacts. The maximum singlet density on the other hand should be sufficiently large to get optical gain. During the presentation a novel top-emitting organic device will be presented that has reduced optical absorption losses at the cathode and therefore has great potential for the use in an electrically pumped organic laser. The structure is a hybrid between a transistor and a diode and minimizes optical absorption and quenching phenomena at the metallic cathode, while still allowing for high current densities. In the device, the metallic cathode is displaced with respect to the light emission zone by one to several microns. This large distance between the cathode and the light-emission zone is bridged by electrons with an enhanced field-effect mobility.