Reducing Open-Circuit Voltage Losses in All-Inorganic Perovskite Cells by Dedoping

作者：Peng, Zijian^*; Tian, Jingjing; Zhang, Kaicheng; These, Albert; Xie, Zhiqiang; Zhao, Yicheng; Osvet, Andres; Guo, Fei; Lueer, Larry; Li, Ning^*; Brabec, Christoph J.^*

来源：ACS Energy Letters, 2023, 8(5): 2077-2085.

DOI：10.1021/acsenergylett.3c00173

• SURFACE PHOTOVOLTAGE SPECTROSCOPY
• SOLAR-CELL
• HETEROJUNCTIONS
• EFFICIENCY

CsPbI2Br is an attractive photovoltaic material due to its promising optoelectronic properties. However, the corresponding perovskite solar cells (PSCs) with p-i-n configuration suffer from low open-circuit voltage (V-OC) and fill factor (FF), limiting their application in tandem solar cells. Here, we propose using the fullerene ICBA as the electron charge transporting layer (ETL), forming a better interfacial contact and enhancing the internal quasi-Fermi level splitting (QFLS). A further reduction of V-OC losses of around 0.1 V was achieved by an ultrathin phenethylammonium chloride (PEACl) layer between the perovskite and the ETL. We precisely study the V-OC improvement and find that passivation of surface recombination contributes only 20 mV, while more importantly, a major increase of 80 mV is achieved by dedoping the perovskite surface, which removes a non-negligible electron extraction barrier. Our results give helpful direction regarding how to further improve V-OC in p-i-n perovskite cells.

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