Optimized Quantum Dot Light-emitting-device with Insulating Layer

We reported the preparation of CdSe/CdS/ZnS based quantum dot light-emitting-devices (QLED) with an ultra-thin PMMA layer. This PMMA layer between the quantum dots layer and the electron-transport layer retards the electron current and results in a more balanced electron and hole injecting into emissive quantum dot layer. The optimized charge balance enhanced the device external quantum efficiency (EQE). The results show that the precise control of the PMMA layer thickness is quite important, otherwise, leading to degraded device efficiency and increased turn on voltage.