Time: 27th June, 2017, 16:00-17:00

Reporter: Shiyou CHEN (East China Normal University)

Location: Seminar room, 2nd floor of Key Laboratory for Special Functional Materials of Ministry of Education

   Prof. Dr. Shiyou CHEN is a researcher of the Key Laboratory of Polarized Materials and Devices of the Ministry of Education in East China Normal University. He received his PhD degree from Fudan University in 2009 and then worked as a deputy research fellow at East China Normal University. He worked as a postdoctoral researcher in the Laurence Berkeley National Laboratory in the United States in the years of 2011-2013 and worked for the joint research center of artificial photosynthesis co-constructed by the laboratory and California Institute of Technology (CIT). Prof. Chen mainly focuses on the theoretical simulation and design of semiconductor photoelectric materials. He has published more than 70 papers with total citations more than 3600 times, mainly studying the design and optimization of the new type of solar cell materials and the physical properties of multiple semiconductors, etc.

   Abstract： Through first-principles calculations, we can calculate the properties of the defects and dopants in new semiconductors and predict whether there are high concentration of deep-level defects or dopants that may act as electron-hole recombination centers, which can accelerate the discovery of photovoltaic semiconductors with high energy-conversion efficiency. In this seminar I will discuss such first-principles study in three semiconductor systems, including the quaternary I2-II-IV-VI4 (Cu2ZnSnS4, Cu2ZnSnSe4, Ag2ZnSnS4, Ag2ZnSnSe4), the ternary I-III-VI2 (CuInSe2 and CuGaSe2) and I-V-VI2 (CuSbS2 and CuSbSe2), which were all proposed as the candidate photovoltaic materials with high efficiency. Based on the calculated formation energies (concentration) and transition energy levels of possible defects and dopants, I will discuss the influence of the chemical composition and growth conditions on the defect formation/ionization and the electrical and optical properties of the samples.