Affiliation:
1. Research School of Engineering The Australian National University Canberra Australian Capital Territory 2601 Australia
2. Centre for Advanced Microscopy The Australian National University Canberra Australian Capital Territory 2601 Australia
3. School of Chemistry The Australian National University Canberra Australian Capital Territory 2601 Australia
4. Faculty of Engineering The University of Sydney Sydney New South Wales 2008 Australia
5. Research School of Physics The Australian National University Canberra Australian Capital Territory 2601 Australia
Abstract
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.