Low‐Temperature Processed Carbon Electrode‐Based Inorganic Perovskite Solar Cells with Enhanced Photovoltaic Performance and Stability

• Published in: Energy & environmental materials (Hoboken, N.J.) Vol. 4; no. 1; pp. 95 - 102
• Main Authors: Wu, Xin, Qi, Feng, Li, Fengzhu, Deng, Xiang, Li, Zhen, Wu, Shengfan, Liu, Tiantian, Liu, Yizhe, Zhang, Jie, Zhu, Zonglong
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.01.2021
• Subjects: bromide incorporation; Carbon; Carrier lifetime; Composition; Energy conversion efficiency; Energy dissipation; Energy loss; Grain boundaries; high performance; Hydrophobicity; Morphology; perovskite; Perovskites; Photovoltaic cells; Photovoltaics; Radiative recombination; Recombination; Solar cells; stable; Thermal stability; VOCs; Volatile organic compounds
• ISSN: 2575-0356; 2575-0356
• DOI: 10.1002/eem2.12089

All‐inorganic perovskite solar cells (PVSCs) have drawn widespread attention for its superior thermal stability. Carbon‐based devices are promising to demonstrate excellent long‐term operational stability due to the hydrophobicity of carbon materials and the abandon of organic hole‐transporting materials (HTMs). However, the difficulty to control the crystallinity process and the poor morphology leads to serious non‐radiative recombination, resulting in low VOC and power conversion efficiency (PCE). In this article, the crystal formation process of all‐inorganic perovskites is controlled with a facile composition engineering strategy. By bromide incorporation, high‐quality perovskite films with large grain and fewer grain boundaries are achieved. As‐prepared perovskite films demonstrate longer carrier lifetime, contributing to lower energy loss and better device performance. Fabricated carbon‐based HTM‐free PVSCs with CsPbI2.33Br0.67 perovskite realized champion PCE of 12.40%, superior to 8.80% of CsPbI3‐based devices, which is one of the highest efficiencies reported for the carbon‐based all‐inorganic PVSCs to date. The high VOC of 1.01 V and FF of 70.98% indicate the significance of this composition engineering method. Moreover, fabricated carbon‐based devices exhibit excellent stability, and unencapsulated device retains over 90% of its initial efficiency under continuous one sun illumination for 250 h in N2 atmosphere and keeps ~84% of its original value after stored in ambient environment with RH 15–20% for 200 h. This work provides a facile way to fabricate high‐performance and stable carbon‐based all‐inorganic PVSCs. This article provides a facile composition engineering method to improve the performance and stability of carbon‐based all‐inorganic perovskite solar cells. By simply bromide incorporation, the morphology and crystallinity of perovskite film are improved, leading to the enhancement of power conversion efficiency to 12.40% with excellent stability, which is among the highest reported efficiencies.