Interfacial Energy Level Tuning for Efficient and Thermostable CsPbI 2 Br Perovskite Solar Cells

• Published in: Advanced science 2020-01, Vol.7 (1), p.1901952
• Main Authors: Shen, En-Chi, Chen, Jing-De, Tian, Yu, Luo, Yu-Xin, Shen, Yang, Sun, Qi, Jin, Teng-Yu, Shi, Guo-Zheng, Li, Yan-Qing, Tang, Jian-Xin
• Format: Article
• Language: English
• Subjects: Contact angle; Efficiency; Energy; Morphology; Optical properties; Photovoltaic cells; Scanning electron microscopy; Spectrum analysis
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.201901952

Inorganic mixed-halide CsPbX -based perovskite solar cells (PeSCs) are emerging as one of the most promising types of PeSCs on account of their thermostability compared to organic-inorganic hybrid counterparts. However, dissatisfactory device performance and high processing temperature impede their development for viable applications. Herein, a facile route is presented for tuning the energy levels and electrical properties of sol-gel-derived ZnO electron transport material (ETM) via the doping of a classical alkali metal carbonate Cs CO . Compared to bare ZnO, Cs CO -doped ZnO possesses more favorable interface energetics in contact with the CsPbI Br perovskite layer, which can reduce the ohmic loss to a negligible level. The optimized PeSCs achieve an improved open-circuit voltage of 1.28 V, together with an increase in fill factor and short-circuit current. The optimized power conversion efficiencies of 16.42% and 14.82% are realized on rigid glass substrate and flexible plastic substrate, respectively. A high thermostability can be simultaneously obtained via defect passivation at the Cs CO -doped ZnO/CsPbI Br interface, and 81% of the initial efficiency is retained after aging for 200 h at 85 °C.