Electroluminescence of ZnO nanorods embedded in a polymer film

Vertically aligned ZnO nanorods (NRs) were grown on a ZnO film and embedded in the poly(3,4 ethyle-nedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) to fabricate a ZnO film/ZnO nanorods/polymer hybrid structured light emitting diode (LED). The embedded ZnO NRs can increase the injected current of the ZnO/PEDOT:PSS heterojunction and play key roles in the emission process. We demonstrate the ZnO NRs are the radiative recombination zone in the LED. Electroluminescence (EL) spectrum of the hybrid LED consists of one ultraviolet (UV) near-band-edge emission peak and two visible deep-level emission peaks. The relative intensities of the three peaks are evidently influenced by the applied voltage, which can be clearly explained by the energy band diagram.