Efficient Solar Cells Based on Light‐Harvesting Antimony Sulfoiodide

Although antimony sulfoiodide (SbSI) exhibits very interesting properties including high photoconductivity, ferroelectricity, and piezoelectricity, it is not applied to solar cells. Meanwhile, SbSI is predominantly prepared as a powder using a high‐temperature, high‐pressure system. Herein, the fabrication of solar cells utilizing SbSI as light harvesters is reported for the first time to the best of knowledge. SbSI is prepared by solution processing, followed by annealing under mild temperature conditions by a reaction between antimony trisulfide, which is deposited by chemical bath deposition on a mesoporous TiO2 electrode and antimony triiodide, under air at a low temperature (90 °C) without any external pressure. The solar cells fabricated using SbSI exhibit a power conversion efficiency of 3.05% under standard illumination conditions of 100 mW cm−2. Solar cells with the configuration of FTO (fluorine‐doped SnO2)/TiO2 blocking layer/mesoporous TiO2/SbSI/hole‐transporting material/Au are demonstrated for the first time. The cells fabricated using TiO2 as an electron‐transporting layer and poly[2,6‐(4,4‐bis(2‐ethylhexyl)‐4H‐cyclopenta[2,1‐b;3,4‐b′]dithiophene)‐alt‐4,7‐(2,1,3‐benzothiadiazole)] as a hole‐transporting layer exhibit a power conversion efficiency of 3.05% under full illumination of air mass 1.5G.