Chang, Li ChunDinh Bui, AnhHuang, KeqingKremer, FelipeBrink, FrankWang, WeiHaggren, AnneMayon, Azul OsorioTa, Xuan Minh ChauDuan, LeipingLem, Olivier Lee CheongHou, YihuiNguyen, Dang ThuanTabi, Grace DansoaZhan, HualinAhmad, ViqarDuong, Thewhite, ThomasWalter, DanielWeber, KlausCatchpole, KylieShen, Heping2025-05-232025-05-23ORCID:/0000-0002-0088-9044/work/184100150ORCID:/0000-0002-6782-7382/work/184101587ORCID:/0000-0002-2421-6178/work/184101826ORCID:/0000-0001-6263-7806/work/184104295ORCID:/0000-0002-1298-4743/work/203091350http://www.scopus.com/inward/record.url?scp=85202628932&partnerID=8YFLogxKhttps://hdl.handle.net/1885/733751306The 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.This work was supported by the Australian Government through the Australian Renewable Energy Agency (ARENA). Responsibility for the views, information, or advice expressed herein is accepted by the Australian Government. The authors acknowledge the instruments and expertise of the ACT node of the NCRIS-enabled Australian National Fabrication Facility (ANFF-ACT). The authors express sincere gratitude to Dr Lachlan Black and Malak Sharif for their invaluable assistance with the Kelvin probe measurements of the energy level. The authors express thanks to James Cotsell, Michael Jambor, Bruce Condon, Maureen Brauers, and Pheng Phang for their dedicated efforts in maintaining the laboratory facilities. The authors acknowledge the instruments and expertise of Microscopy Australia at the Centre for Advanced Microscopy, Australian National University, a facility that is funded by the University and the Federal Government through National Collaborative Research Infrastructure Strategy (NCRIS).enPublisher Copyright: © 2024 The Author(s). Solar RRL published by Wiley-VCH GmbH.inverted perovskite solar cellpoly-TPDwide-bandgap202410.1002/solr.20240039185202628932