LAUSR

The role of transition metal oxides (TMOs) based intermediate connectors in tandem organic light emitting diodes (OLEDs) has been studied via capacitance-voltage and current-voltage characteristics, in order to elucidate the dynamic processes of charges generation and transport within externally applied voltages. The TMO-based intermediate connectors are composed of molybdenum trioxide (MoO3) and cesium azide (CsN3)-doped-4, 7–diphenyl-1, 10-phenanthroline (BPhen) layers, where MoO3 and CsN3 are used due to low deposition temperatures. From the obtained results of capacitance and current density, charges generation in CsN3:BPhen/MoO3/NPB is proposed to the defect states in thermally evaporated MoO3, which offers a minimal energy offset for charges generation. Moreover, our results clearly indicate that charges generation efficiency is not only relying on the MoO3-NPB interface, but also influenced by CsN3:BPhen-MoO3 interface. CsN3 doped BPhen layer further improves charges separation efficiency, which finally results in favorable charges transport into the adjacent layers and ensure to function efficiently for tandem OLEDs.