Highly thermal-stable organic light-emitting diodes with a bulk heterojunction interfacial modification layer

Abstract We report highly thermal-stable organic light-emitting diodes (OLEDs) by introducing an interfacial modification layer (IML), consisting of the N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-benzidine (NPB):MoO 3 bulk heterojunction. The IML can increase the thermal resistance of 4,4′-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC) hole transport layer to be higher than its glass transition temperature. The OLED with the IML can endure a high temperature of 100 °C with a current efficiency of 51.82 cd A −1 and a low-efficiency roll-off. The optimized thermal stability of OLED is not only due to the thermally stable IML but also resulted from the well-matched energy level between anode and TAPC with the help of IML.