Yusuf, ASMarkwitz, MChen, ZRamezani, MKennedy, JVFiedler, H2025-11-032025-11-032025-10-14Applied Physics A: Materials Science and Processing, ISSN: 0947-8396 (Print); 1432-0630 (Online), Springer Science and Business Media LLC, 131(11), 859-. doi: 10.1007/s00339-025-08975-00947-83961432-0630http://hdl.handle.net/10292/20051Perovskite solar cells (PSCs) have emerged as a revolutionary photovoltaic technology, achieving remarkable power conversion efficiencies (PCEs) above 26.61%, while offering low-cost and scalable fabrication. Among the critical components of PSCs, the electron transport layer (ETL) plays a vital role in charge extraction, transport, and recombination suppression. This review provides a comprehensive analysis of recent advancements in inorganic ETLs, particularly focusing on widely studied materials such as TiO<inf>2</inf>, SnO<inf>2</inf>, and ZnO. While TiO<inf>2</inf> has historically been the benchmark ETL, challenges such as high-temperature processing and photocatalytic instability have led researchers to explore alternative materials. SnO₂ has gained prominence due to its superior electron mobility, low temperature processability, and excellent optical transparency, making it a strong candidate for high-performance PSCs. ZnO, with its high conductivity and facile synthesis, also shows promise, but faces stability concerns. The review further highlights the significance of surface modifications, doping strategies, and interface engineering to optimize charge transport dynamics and enhance device longevity. Additionally, we discuss emerging alternatives and future perspectives on scalable, cost-effective, and stable ETLs that could drive PSCs toward commercialization. By bridging fundamental material properties with device performance, this work provides insights into the next generation of high-efficiency and durable PSCs.© The Author(s) 2025. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.40 Engineering4016 Materials Engineering7 Affordable and Clean Energy0204 Condensed Matter Physics0205 Optical Physics0912 Materials EngineeringApplied Physics4016 Materials engineering5102 Atomic, molecular and optical physics5104 Condensed matter physicsJournal ArticleOpenAccess10.1007/s00339-025-08975-0