Formation of Stable Tin Perovskites Co-crystallized with Three Halides for Carbon-Based Mesoscopic Lead-Free Perovskite Solar Cells
Journal
Angewandte Chemie (International ed. in English)
Journal Volume
56
Journal Issue
44
Pages
13819
Date Issued
2017-10-23
Author(s)
Tsai, Cheng-Min
Mohanta, Nayantara
Wang, Chi-Yung
Lin, Yu-Pei
Yang, Yaw-Wen
Hung, Chen-Hsiung
Diau, Eric Wei-Guang
Abstract
We synthesized and characterized methylammonium (MA) mixed tri-halide tin perovskites (MASnIBr2-x Clx ) 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-y Bry and MASnCl3-z Brz in the stoichiometric proportions of their precursors, confirmed by XRD. A device with MASnIBr1.8 Cl0.2 (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 MASnIBr1.8 Cl0.2 cell. Transient PL decays showed the intrinsic problem of tin-based perovskites with average lifetimes less than 100 ps.
Subjects
carbon electrodes; halides; perovskites; solar cells; tin
Type
journal article