The design and performance optimization of all-inorganic CsPbIBr2/CsSnI3 heterojunction perovskite solar cells
Conglu Ming, Hao Zhou, Jiang Wu, Chen Hu, Weikai Fan, Xinxia Ma, Zhuoxiong Zeng, Yongfeng Qi, Jiaqi Shi, Shikai Qiao
Abstract
With the fast growth of perovskite solar cells (PSCs), inorganic perovskite, represented by Cs-based perovskite, consistently surpasses organic perovskite solar cells in regards of photovoltaic performance. Among them, CsPbIBr 2 materials stand out for their excellent efficiency and stability in all-inorganic PSCs. Unfortunately, poor solar energy utilization results from the CsPbIBr 2 ′s wide band gap, which severely limits light harvesting. This work proposes an all-inorganic CsPbIBr 2 /CsSnI 3 heterojunction using CsSnI 3 instead of HTL based on the matched band structure of CsSnI 3 and CsPbIBr 2 , then simulations and optimizes it using SCAPS-1D software to increase solar energy utilization and cell efficiency. The results show that the CsPbIBr 2 /CsSnI 3 perovskite heterojunction PSC extends the absorption spectral wavelength range from 600 nm in the visible area to 960 nm in the near-infrared region, which greatly improves solar energy utilization and is more favorable to photogenerated carrier migration. The device's performance is ideal after optimization when Voc = 1.0344 V, Jsc = 39.36 mA/cm 2 , FF = 89.43%, and PCE = 36.41%. The device efficiency of the optimized CsPbIBr 2 /CsSnI 3 heterojunction is 36.41%, which is significantly higher than the PCE of 5.45% for a single layer of CsPbIBr 2 . Moreover, the CsPbIBr 2 /CsSnI 3 solar cell can respond to near-infrared light, enabling it to generate power at night. Consequently, this work reveals that the constructed CsPbIBr 2 /CsSnI 3 heterojunction PSCs can enable the bright future of Cs-based inorganic PSCs for practical applications in photovoltaics and optoelectronics.