Hot carriers are generated when a material absorbs photons with energies greater than its bandgap. One of the main energy losses in optoelectronics is the relaxation of hot carriers in materials through phonon emission. Despite its potential, effectively utilizing hot carriers in light conversion devices remains a major challenge. In this presentation, I will introduce the recent discovery of slow hot carrier cooling in halide perovskites, which has opened up new possibilities for utilizing the energy of hot carriers. The focus of my talk will be our recent research on hot carrier dynamics using ultrafast optical spectroscopy in perovskite optoelectronic devices. I will present our findings on the efficient hot carrier-induced multiple exciton generation in photodetection devices based on perovskite quantum dots. Additionally, I will discuss our work on directly extracting hot carriers for hot-carrier photocurrent generation in a 2D perovskite/TMDCs device. Furthermore, I will introduce the pioneering development of a hot carrier solar cell based on the perovskite quantum dots. These results demonstrate the potential of utilizing hot carriers in perovskite materials, offering promising avenues for the advancement of efficient solar cells and highly efficient optoelectronic devices.
 

Li Mingjie is an Assistant Professor in the Department of Applied Physics at The Hong Kong Polytechnic University. Before Joining PolyU in 2019, he obtained his Ph.D. degree in Physics and Applied Physics from Nanyang Technology University and worked at KLA Corp., NTU and NUS as a Research Scientist and Research Fellow, respectively. His research interests include using ultrafast optical spectroscopies to investigate carrier/spin dynamics and novel photophysics in optical materials and optoelectronic devices.

Please contact phweb@ust.hk should you have questions about the talk.