Electrochemical Characterization of Mn doped Tin Halide Perovskite

Reference	Presenter	Authors (Institution)	Abstract
06-185	Margaret Dawson	Dawson, M.(Universidade Federal de Sao Carlos); Soares, G.B.(Universidade Estadual Paulista, Araraquara); Morelli, M.R.(Universidade Federal de São Carlos); Ribeiro, C.(Brazilian Agricultural Research Corporation, São Carlos, SP, Brazil);	Tin halide perovskite (CH3NH3SnI3) is a promising light absorber material which has received a lot of attention as a replacement of CH3NH3PbI3. While there has been a great deal of research on the photovoltaic properties of CH3NH3SnI3, less attention has been paid to its electrochemical properties, although they provide useful information on charge transfer and transport processes. In this regard, CH3NH3SnI3 and Mn doped CH3NH3SnI3 films were synthesized by one step method and were characterized by X-ray diffraction, Scanning electron microscopy, Electrochemical impedance spectroscopy, Cyclic and Linear sweep voltammetry in nonpolar solvent. CH3NH3SnI3 and Mn doped CH3NH3SnI3 presented the tetragonal phase. The Nyquist plots indicate both grain and grain boundary contributions in the CH3NH3SnI3 and Mn doped CH3NH3SnI3 films. The grain and grain boundary resistance of Mn doped CH3NH3SnI3 is higher than that of CH3NH3SnI3 due to the larger crystallite size of the former. At medium frequencies, the charge-transfer resistance of CH3NH3SnI3 was lower than Mn doped CH3NH3SnI3 films. Also, at low frequencies, the transfer process in CH3NH3SnI3 is diffusion controlled. On the contrary, the contribution of diffusion is diminished in Mn doped CH3NH3SnI3 which suggests that ion diffusion was altered through Mn incorporation. From the cyclic voltammetry analysis, both Mn doped CH3NH3SnI3 and CH3NH3SnI3 showed hysteresis, a characteristic of metal halide perovskites. These results demonstrate that the electronic properties of CH3NH3SnI3 are modified with doping and these properties can be elucidated by electrochemical analysis. Further analysis of charge transfer and transport processes through electrochemical characterization is in progress.
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