Enhanced Efficiency and Stability for the Inverted High‐Bandgap Perovskite Solar Cell via Bottom Passivation Strategy

• DOI: 10.1002/solr.202400391
• Publication Date: 2024-08-29T07:22:07Z
• Authors: Li‐Chun Chang; Anh Dinh Bui; Keqing Huang; Felipe Kremer; Frank Brink; Wei Wang; Anne Haggren; Azul Osorio Mayon; Xuan Minh Chau Ta; Leiping Duan; Olivier Lee Cheon...; Yihui Hou; Dang‐Thuan Nguyen; Grace Dansoa Tabi; Hualin Zhan; Viqar Ahmad; The Duong; Thomas white; Daniel Walter; Klaus Weber; Kylie Catchpole; Heping Shen
• Keywords: 0301 basic medicine; 03 medical and health sciences

The bottom perovskite with the hole transport layer (HTL) in inverted perovskite solar cells (PSCs) interface has received little attention due to challenges like interlayer dissolution during perovskite deposition. And voids at the perovskite/HTL interface can degrade cell performance. This work introduces a two‐dimensional (2D) perovskite layer between the perovskite and poly (N, N′‐bis‐4‐butylphenyl‐N, N′‐bisphenyl) benzidine (Poly‐TPD) HTL using a mixed solution of 4‐methylphenethylammonium chloride (4M‐PEA‐Cl), methylammonium iodide (MA‐I), and Poly(9,9‐bis(3′‐(N,N‐dimethyl)‐N‐ethylammoinium‐propyl‐2,7‐fluorene)‐alt‐2,7‐(9,9‐dioctylfluorene))dibromide (PFN‐Br). The amine functional groups in the organic salts improved HTL wettability, resulting in a void‐free interface. 4M‐PEA‐Cl, with its strong electron‐withdrawing benzene ring, outperformed other amine‐containing salts in passivating undercoordinated Pb2+ ions. Incorporating this hybrid passivation layer in PSCs resulted in a 1.8% absolute increase in power conversion efficiency (PCE) to 19.1% with 1.68 eV perovskite bandgap. Additionally, the passivated PSCs demonstrated enhanced operational stability, retaining 91% of their initial efficiency after 800 hours of continuous 1‐sun illumination, compared to 84.7% for the control sample.