Reporter: Haiming Zhu, researcher, Department of chemistry, Zhejiang University

Introduction:

A researcher in the Department of chemistry of Zhejiang University. He graduated from the University of science and technology of China with a bachelor's degree in Chemical Physics in 2008 and Emory University of the United States with a doctor's degree in physical chemistry in 2014. From 2014 to 2016, he did postdoctoral research in the University of Columbia of the United States. He is mainly engaged in the research of low-dimensional semiconductor materials and high-tech materials by ultrafast time-resolved laser spectroscopy. He has been supported by the overseas high-level talent introduction program and the excellent youth fund of NSFC. He has published more than 80 articles in Science, Nature Materials, Science Advances, Nature Communications and other journals.

Abstract:

New low dimensional semiconductor materials show unique advantages and prospects in the field of photoelectric conversion. The excited state dynamics of photoelectric conversion materials after absorbing light directly determines the performance optimization and design principle of photoelectric conversion devices, which plays an important guiding role. In traditional three position covalent semiconductors (silicon, gallium arsenide, etc.), due to the weak electron lattice interaction, the free electron or exciton image based on energy band is often enough to describe the dynamic behavior of excited state carriers. However, in new low dimensional semiconductors, due to polar or soft lattices and weak interactions between lattices, molecular like behavior often appears, including strong electron phonon interaction. The motion of electrons will be strongly coupled with the lattice to form polarons, and the traditional image is no longer tenable. The coupled electron lattice motion will essentially change the dynamic behavior of excited carriers in these materials and bring new physicochemical properties. In this report, we will take two-dimensional lead halide perovskite and tellurium sulfide (selenium) with quasi one-dimensional structure as examples to reveal the electron lattice motion of excited state coupling, the formation of large (small) polarons, and the effects on excited state properties and dynamics, including abnormal exciton spin dynamics, fluorescence tailing and intrinsic energy loss.

References:

1. Tao, W.; Zhang, C.; Zhou, Q.; Zhao, Y.; Zhu, H.*, Momentarily trapped exciton polaron in two-dimensional lead halide perovskites. Nat. Commun. 2021, 12 (1), 1400.

    2. Tao, W.; Zhou, Q.; Zhu, H.*, Dynamic polaronic screening for anomalous exciton spin relaxation in two-dimensional lead halide perovskites. Sci. Adv. 2  020, 6 (47), eabb7132.

    3. Yang, Z.; Wang, X.; Chen, Y.; Zheng, Z.; Chen, Z.; Xu, W.; Liu, W.; Yang, Y.; Zhao, J.; Chen, T.; Zhu, H.*, Ultrafast self-trapping of photoexcited carriers sets the upper limit on antimony trisulfide photovoltaic devices. Nat. Commun. 2019, 10 (1), 4540.

   

   Report time: 9:00, July 27, 2021 (Tuesday)

   Report location: conference room 504, life Science Building

   Tencent conference: Conference Number: 529 258 986