Enhanced Performance of Organic Light Emitting Device by Incorporating 4,4-Bis(2,2-diphenylvinyl)-1,1-Biphenyl as an Efficient Hole-Injection Nano-Layer

Abstract

Here we reported that 4,4-bis(2,2-diphenylvinyl)-1,1-biphenyl (DPVBi), known as blue emitting host material, could effectively manipulate the Schottky energy barrier between the indium tin oxide (ITO) and the emitting layer and thus significantly enhanced hole injection property. As a result, we could greatly improve the current and luminance efficiencies of organic light emitting diodes (OLEDs) as well as their stability. We attributed the enhanced performance of hole injection layer (HIL)-modified OLEDs to the lowered hole injection barrier. By analyzing the J-V characteristics of hole only devices as a function of temperature, we could show that the interfacial energy barrier between ITO and emitting layer was reduced by more than 0.2 eV by insertion of DPVBi HIL.