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Formation of Stable Tin Perovskites Co‐crystallized with Three Halides for Carbon‐Based Mesoscopic Lead‐Free Perovskite Solar Cells
Author(s) -
Tsai ChengMin,
Mohanta Nayantara,
Wang ChiYung,
Lin YuPei,
Yang YawWen,
Wang ChienLung,
Hung ChenHsiung,
Diau Eric WeiGuang
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201707037
Subject(s) - tin , halide , perovskite (structure) , materials science , stoichiometry , phase (matter) , chemistry , analytical chemistry (journal) , inorganic chemistry , crystallography , organic chemistry , chromatography , metallurgy
We synthesized and characterized methylammonium (MA) mixed tri‐halide tin perovskites (MASnIBr 2− x Cl x ) for carbon‐based mesoscopic solar cells free of lead and hole‐transporting layers. Varied SnCl 2 /SnBr 2 ratios yielded tin perovskites with three halides (I, Br, and Cl) co‐crystallized inside the tin‐perovskite. When the SnCl 2 proportion was ≥50 % ( x ≥1), phase separation occurred to give MASnI 3− y Br y and MASnCl 3− z Br z in the stoichiometric proportions of their precursors, confirmed by XRD. A device with MASnIBr 1.8 Cl 0.2 (SnCl 2 =10 %) showed the best photovoltaic performance: J SC =14.0 mA cm −2 , V OC =380 mV, FF=0.573, and PCE=3.1 %, and long‐term stability. Electrochemical impedance spectra (EIS) show superior charge recombination and dielectric relaxation properties for the MASnIBr 1.8 Cl 0.2 cell. Transient PL decays showed the intrinsic problem of tin‐based perovskites with average lifetimes less than 100 ps.