Tsai, Cheng-MinCheng-MinTsaiMohanta, NayantaraNayantaraMohantaWang, Chi-YungChi-YungWangLin, Yu-PeiYu-PeiLinYang, Yaw-WenYaw-WenYangCHIEN LUNG WANGHung, Chen-HsiungChen-HsiungHungDiau, Eric Wei-GuangEric Wei-GuangDiau2023-11-062023-11-062017-10-2314337851https://scholars.lib.ntu.edu.tw/handle/123456789/636845We 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.encarbon electrodes; halides; perovskites; solar cells; tinjournal article10.1002/anie.201707037288727472-s2.0-85030084834https://api.elsevier.com/content/abstract/scopus_id/85030084834