First-Principles Investigation On The Photovoltaic Properties Of Lead Free Earth Abundant (Ch3nh3)(2)Sni6 Perovskite

The issue of toxicity and chemical stability are two concerns for organic-inorganic hybrid perovskites, impeding their further commercial applications. Double perovskite (CH3NH3)(2)SnI6 with a bandgap of 1.81eV and stable chemical valence of Sn (+4) is considered as a promising alternative. By first-principles calculations, the electronic properties, defect physics, and interface engineering of the perovskite are investigated in this work. It is found that (i) MA(2)SnI(6) has a direct bandgap with a large dispersion of a lower conduction band. Due to the direct I 5p-5p transition between band edges, the light absorption can be as high as 10(5)cm(-1) in the visible range. (ii) An Sn rich and I poor condition is suggested when MA(2)SnI(6) is used as an electron transporting material (ETM) because of its high n-type electronic conductivity. An Sn poor and I rich condition is proposed when MA(2)SnI(6) is prepared for photovoltaic application, because it can suppress the formation of non-radiation centers. (iii) ICBA and Spiro are proposed to be suitable ETM and hole transporting material, respectively, in MA(2)SnI(6) based solar cells.