Modena - 08.06.2018 - S3 Seminar Koichi Yamashita
Date and Time: Friday June 8, 2018 - 11.00
Venue: S3 Seminar room, third floor, Physics Building, FIM Department

Title: Charge Separation and Charge Carrier Trapping of Lead Iodide Perovskites

Speaker: Koichi Yamashita
Department of Chemical System Engineering, Graduate School of Engineering, University of Tokyo, Japan

Abstract: The high performance of recently emerged lead halide perovskite-based photovoltaic devices has been attributed to remarkable carrier properties in this kind of material:long carrier diffusion length, long carrier lifetime, and low electron-hole recombination rate. However, the mechanism of the charge separation is still not fully understood. In my talk, it will be demonstrated that the charge separation is induced by the structural fluctuation of the inorganic lattice using first-principles molecular dynamics simulations [1]. On the other hand, charge carrier trapping at defects on surfaces or grain boundaries is detrimental for the performance of perovskite solar cells. In practice, it is one of the main limiting factors for carrier lifetime. Surface defects responsible for carrier trapping are clarified by comprehensive first-principles investigations and it is proposed that PbI2-rich condition is preferred to MAI-rich one, while intermediate condition has possibility to be the best choice[2].

[1] H. Uratani and K. Yamashita, J. Phys. Chem. C, 121, 26648−26654 (2017).
[2] H. Uratani and K. Yamashita, J. Phys. Chem. Lett., 8, 742−746 (2017).

Host: Carlo Andrea Rozzi


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