Universal Strategy with Structural and Chemical Crosslinking Interface for Efficient and Stable Perovskite Solar Cells
Keqing Huang, Li‐Chun Chang, Yihui Hou, W. F. Ji, Thành Trần‐Phú, Anh Dinh Bui, Azul Osorio Mayon, Wei Wang, Olivier Lee Cheong Lem, Dang‐Thuan Nguyen, Grace Dansoa Tabi, Leiping Duan, Yun Liu, Heping Shen, Junliang Yang, Thomas P. White, Kylie Catchpole, Klaus Weber, The Duong
Abstract
Abstract Due to the limited interface contact and weak interfacial interaction, planar heterojunction perovskite solar cells (PSCs) have space for further improvement. Herein, a structural and chemical crosslinking interface is proposed and constructed by introducing an extra layer, which blends tin dioxide (SnO 2 ) nanoparticles with chloride salts. Since the incorporated materials can be dissolved during the fabrication of perovskite, the quality of perovskite films is improved, leading to larger grain size and reduced trap‐state density. Also, more chloride ions at the SnO 2 /perovskite interface are observed and the interaction between Cl − and Sn 4+ is confirmed. It results in more pronounced n‐type SnO 2 with better conductivity and deeper conduction bands, leading to preferable energy level alignment between SnO 2 and perovskite. Consequently, the open‐circuit voltage and fill factor of the devices increase, and target cells present better stability, retaining 98% of initial efficiencies after >10 000 h storage in dry air (≈5% relative humidity) and maintaining 85.50% of the initial efficiency after 1000 h of operation under light. This strategy enables the achievement of 25.28% efficiency with a low bandgap (1.53 eV) perovskite composition, and it is confirmed to be universal when other related materials are utilized.