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Formation of Stable Tin Perovskites Co‐crystallized with Three Halides for Carbon‐Based Mesoscopic Lead‐Free Perovskite Solar Cells

DOI

110

Citations

27

References

2017

Year

C. C. Tsai, Nayantara Mohanta, Chi‐Yung Wang, Yu‐Pei Lin, Yaw‐Wen Yang, Chien‐Lung Wang, Chen‐Hsiung Hung, Eric Wei‐Guang Diau
Angewandte Chemie International Edition

Abstract

We synthesized and characterized methylammonium (MA) mixed tri-halide tin perovskites (MASnIBr<sub>2-x</sub> Cl<sub>x</sub> ) for carbon-based mesoscopic solar cells free of lead and hole-transporting layers. Varied SnCl<sub>2</sub> /SnBr<sub>2</sub> ratios yielded tin perovskites with three halides (I, Br, and Cl) co-crystallized inside the tin-perovskite. When the SnCl<sub>2</sub> proportion was ≥50 % (x≥1), phase separation occurred to give MASnI<sub>3-y</sub> Br<sub>y</sub> and MASnCl<sub>3-z</sub> Br<sub>z</sub> in the stoichiometric proportions of their precursors, confirmed by XRD. A device with MASnIBr<sub>1.8</sub> Cl<sub>0.2</sub> (SnCl<sub>2</sub> =10 %) showed the best photovoltaic performance: J<sub>SC</sub> =14.0 mA cm<sup>-2</sup> , V<sub>OC</sub> =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<sub>1.8</sub> Cl<sub>0.2</sub> cell. Transient PL decays showed the intrinsic problem of tin-based perovskites with average lifetimes less than 100 ps.

References

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