Efficient Quantum Dots Light-Emitting Devices Using Polyvinyl Pyrrolidone-Capped ZnO Nanoparticles With Enhanced Charge Transport

We propose effective charge balance CdSe/ZnS quantum dots-based light-emitting devices (QLEDs) using polyvinyl pyrrolidone (PVP)-capped ZnO nanoparticles (NPs) synthesized by sol-gel process as electron transport layer. In general, ZnO NPs have a trap-site induced from oxygen vacancies. An oxygen vacancy captures electrons and reduces the performance of QLEDs. In order to reduce the oxygen vacancies and improve performance, we used PVP for modifying the surface of ZnO NPs. This modification significantly enhanced the luminance and current efficiency of the resulting PVP-capped ZnO NPs-based QLEDs to more than 1.5 times of their values in uncapped ZnO NPs-based QLEDs.