Speaker: Professor Xie ZHANG
Institution: Materials and Energy Division, Beijing Computational Science Research Center
Hosted by: Professor Haibin SU
Zoom Link: https://hkust.zoom.us/j/98086093182?pwd=TzBmbzVlTVNlZ1NNKzkxNk5NWGE5dz09
Halide perovskites are highly efficient optoelectronic materials; the power conversion efficiency of perovskite solar cells has reached 25.5%, being already comparable with that of single-crystalline silicon cells (26.1%). To understand the fundamental origin of the superior performance, carrier recombination mechanisms are crucial. In recent years, we have developed a full set of first-principles approaches that allow to quantitatively compute the carrier recombination rates and to understand the underlying recombination mechanisms. I will present a number of critical insights into the radiative [1-2] and nonradiative [3-8] recombination mechanisms in halide perovskites obtained by applying our methodology to this technologically important system.
 X. Zhang, J.-X. Shen, and C. G. Van de Walle, J. Phys. Chem. Lett. 9, 2903 (2018).
 X. Zhang, J.-X. Shen, W. Wang, and C. G. Van de Walle, ACS Energy Lett. 3, 2329 (2018).
 J.-X. Shen, X. Zhang, S. Das, E. Kioupakis, and C. G. Van de Walle, Adv. Energy Mater. 8, 1801027 (2018).
 X. Zhang, J.-X. Shen, and C. G. Van de Walle, Adv. Energy Mater. 10, 1902830 (2020).
 X. Zhang, M. E. Turiansky, J.-X. Shen, and C. G. Van de Walle, Phys. Rev. B 101, 140101 (2020).
 X. Zhang, M. E. Turiansky, and C. G. Van de Walle, J. Phys. Chem. C 124, 6022 (2020).
 X. Zhang, J.-X. Shen, M. E. Turiansky, and C. G. Van de Walle, J. Mater. Chem. A 8, 12964 (2020).
 X. Zhang, J.-X. Shen, M. E. Turiansky, and C. G. Van de Walle, Nat. Mater. (2021). [DOI: 10.1038/s41563-021-00986-5]
About the speaker
Prof. Xie Zhang received his Ph.D. in 2015 from the Department of Computational Materials Design led by Prof. Neugebauer at the Max-Planck-Institut für Eisenforschung GmbH and Ruhr-Universität Bochum. He continued working on phase transformations in alloys as a postdoc until December 2016. After joining the group of Prof. Van de Walle at the University of California, Santa Barbara in 2017, he focused on computing and understanding the fundamental recombination mechanisms in optoelectronic materials from first principles. In December 2021, he joined the Beijing Computational Science Research Center as an assistant professor. He received the Early Career HPC achievement award from the National Energy Research Scientific Computing Center (NERSC) in the United States in 2019 for producing “essential insights into recombination mechanisms in hybrid perovskites.” In recent years, he has published a series of articles in high-profile journals such as Nature Materials, Nature Communications, Advanced Energy Materials, Science Advances, and Physical Review Letters.