surface regulation of 3D perovskite using diethylammonium iodide for highly efficient perovskite solar cells

• Published in: Physical chemistry chemical physics : PCCP Vol. 25; no. 13; pp. 9349 - 9356
• Main Authors: Yue, Xiaopeng, Yang, Yingying, Zhao, Xing, Fan, Bingbing, Yan, Huilin, Qu, Shujie, Zhang, Qiang, Lan, Zhineng, Du, Shuxian, Huang, Hao, Yan, Luyao, Wang, Xinxin, Cui, Peng, Ma, Junfeng, Li, Meicheng
• Format: Journal Article
• Published: 29.03.2023
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d2cp05535j

Surface passivation by constructing a 2D/3D structure is considered to be an effective strategy for suppressing non-radiative recombination and improving the device efficiency and stability. Herein, the 2D perovskite is formed in situ on the surface of a 3D perovskite via chemical interactions between diethylammonium iodide (DAI) and Pb-I octahedra, which greatly reduces the deep level defects and non-radiative recombination. Moreover, the 2D/3D structure can regulate the energy level alignment, enhance the charge extraction, and improve the open-circuit voltage. Finally, compared with the control device, the power conversion efficiency (PCE) of the DAI-treated device increases from 21.58 to 23.50%. The unencapsulated devices stored in air for more than 500 hours can still retain 97% of their initial PCE, revealing good long-term placement stability. This work provides a promising strategy to fabricate efficient PSCs through the in situ construction of 2D/3D perovskite heterojunctions. Diethylammonium iodide is used for the first time to regulate the 3D perovskite surface via the in situ formation of 2D perovskite. The target device achieves a high efficiency of 23.50% with negligible hysteresis.