Abstract
Carbon-based CsPbIBr2 inorganic perovskite solar cells (PSCs) have emerged as one of the most promising photovoltaic devices owing to their excellent stability and simple fabrication process. Nevertheless, the efficiency of state-of-the-art carbon-based CsPbIBr2 PSCs is far from satisfactory due to the poor quality of CsPbIBr2 perovskite film. Herein, we prepare the high-quality CsPbIBr2 perovskite film through a one-step spin-coating method by optimizing both the substrate pre-heating temperature and the post-annealing temperature. The optimization of the substrate pre-heating and post-annealing temperatures greatly improves the coverage and crystallinity of CsPbIBr2 perovskite films, leading to enhanced light harvest and suppressed charge recombination. With the CsPbIBr2 perovskite film prepared at the optimized substrate pre-heating and post-annealing temperatures, the fabricated carbon-based CsPbIBr2 PSC with a simple structure of FTO/TiO2/CsPbIBr2/carbon exhibits a gratifying conversion efficiency of 8.10% with a high open-circuit voltage of 1.27 V. Moreover, the fabricated carbon-based CsPbIBr2 PSC without any encapsulation shows an excellent long-term stability under ambient condition. (c) 2020 Elsevier Ltd. All rights reserved.