Patent ID: 7807275
Filing Date: 2010-10-05
Classification: H01L,Y10S,Y10T

Abstract:
1. A device comprising: an anode and a cathode; an emissive layer disposed between and electrically connected to the anode and the cathode, the emissive layer comprising an organic host and an organic dopant; an organic hole transport layer between the anode and the emissive layer; an organic electron transport layer between the cathode and the emissive layer, wherein said electron transport layer is a single layer and is the only layer between the cathode and the emissive layer, the HOMO level of the organic host is no more than 0.8 eV below the HOMO level of the hole transport layer, the LUMO level of the organic host is no more than 0.4 eV above the LUMO level of the electron transport layer, the HOMO level of the electron transport layer is no more than 0.4 eV below the HOMO level of the host, the HOMO and LUMO levels being calculated by density functional calculation, and wherein there is a triplet recombination zone within the emissive layer not more than 10% of the thickness of the emissive layer away from an interface between the emissive layer with the hole transport layer.