title: Solvent-Mediated Crystallization of CH3NH3SnI3 Films for Heterojunction Depleted Perovskite Solar Cells.
abstract: Organo-lead halide perovskite solar cells have gained enormous significance and have now achieved power conversion efficiencies of ∼20%. However, the potential toxicity of lead in these systems raises environmental concerns for widespread deployment. Here we investigate solvent effects on the crystallization of the lead-free methylammonium tin triiodide (CH3NH3SnI3) perovskite films in a solution growth process. Highly uniform, pinhole-free perovskite films are obtained from a dimethyl sulfoxide (DMSO) solution via a transitional SnI2·3DMSO intermediate phase. This high-quality perovskite film enables the realization of heterojunction depleted solar cells based on mesoporous TiO2 layer but in the absence of any hole-transporting material with an unprecedented photocurrent up to 21 mA cm(-2). Charge extraction and transient photovoltage decay measurements reveal high carrier densities in the CH3NH3SnI3 perovskite device which are one order of magnitude larger than CH3NH3PbI3-based devices but with comparable recombination lifetimes in both devices. The relatively high background dark carrier density of the Sn-based perovskite is responsible for the lower photovoltaic efficiency in comparison to the Pb-based analogues. These results provide important progress toward achieving improved perovskite morphology control in realizing solution-processed highly efficient lead-free perovskite solar cells.
authors: Department of Chemistry and ‡Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors: Feng
authors: F
authors: Hao
authors: Department of Chemistry and ‡Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors: Constantinos C
authors: CC
authors: Stoumpos
authors: Department of Chemistry and ‡Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors: Peijun
authors: P
authors: Guo
authors: Department of Chemistry and ‡Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors: Nanjia
authors: N
authors: Zhou
authors: Department of Chemistry and ‡Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors: Tobin J
authors: TJ
authors: Marks
authors: Department of Chemistry and ‡Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors: Robert P H
authors: RP
authors: Chang
authors: Department of Chemistry and ‡Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors: Mercouri G
authors: MG
authors: Kanatzidis