Abstract
We synthesized and characterized methylammonium (MA) mixed tri-halide tin perovskites (MASnIBr2−xClx) for carbon-based mesoscopic solar cells free of lead and hole-transporting layers. Varied SnCl2/SnBr2 ratios yielded tin perovskites with three halides (I, Br, and Cl) co-crystallized inside the tin-perovskite. When the SnCl2 proportion was ≥50 % (x≥1), phase separation occurred to give MASnI3−yBry and MASnCl3−zBrz in the stoichiometric proportions of their precursors, confirmed by XRD. A device with MASnIBr1.8Cl0.2 (SnCl2=10 %) showed the best photovoltaic performance: JSC=14.0 mA cm−2, VOC=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 MASnIBr1.8Cl0.2 cell. Transient PL decays showed the intrinsic problem of tin-based perovskites with average lifetimes less than 100 ps.
Original language | English |
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Pages (from-to) | 13819-13823 |
Number of pages | 5 |
Journal | Angewandte Chemie - International Edition |
Volume | 56 |
Issue number | 44 |
DOIs | |
State | Published - 23 Oct 2017 |
Keywords
- carbon electrodes
- halides
- perovskites
- solar cells
- tin