Operationally Stable Perovskite Light Emitting Diodes at High Radiance

In this project, we intend to fill the knowledge gap on the degradation mechanism of perovskite light emitting diodes (PeLEDs) and demonstrate PeLEDs that can be operated stably at high brightness/radiance. The objectives that we hope to achieve will lay the foundations for the application of PeLEDs as the next generation light source. We will first embark on fundamental research to elucidate the factors that determine operational stability of PeLEDs, with the hypothesis that the degradation mechanism can be the complex of ion migration, electrochemical reactions, imbalanced charge injection and Joule heating, etc. This requires the design of dedicated control experiments and various in-depth characterizations on films, testing devices and PeLEDs. In the second stage, the identified degradation mechanisms will serve as the guidelines for us to design and fabricate novel perovskite films, auxiliary layers as well as device stacks that can mitigate the device degradation. We will perform three main iterations on material and device innovation, starting from the know-how, which has already existed within the host groups, on the preparation of various types of perovskite films and on the fabrication of stable PeLEDs with half lifetime over 100 h at 100 mA/cm2.  To the end of the project, we target for PeLEDs with external quantum efficiency (EQE) > 15% and half lifetime > 1000 h at operating current density > 100 mA/cm2, which is far beyond state of the art.