Jang, Yoon Hee Lee, Youngseok Seo, Hyeon Sik Lee, Haram Lim, Kyoung-jin Lee, Jung-Kun Heo, Jaeyeong Kim, Inho Lee, Doh-Kwon 2025-06-05T02:00:57Z 2025-06-05T02:00:57Z 2025-06-04 2025-05 https://pubs.kist.re.kr/handle/201004/152565 Efficient monolithic perovskite/Si tandem solar cells require a robust recombination junction (RJ) with excellent electrical and optical properties. This study introduces an interface engineering method using an organic sacrificial layer to enable effective monolithic integration. An ultrathin layer of poly(3,4-ethylene-dioxythiophene):polystyrene sulfonate (PEDOT:PSS) is inserted between the transparent conductive oxide recombination layer and the hole transport layer (HTL) of a methylammonium lead iodide (MAPbI(3))-based perovskite top cell. This layer restores junction functionality and enables charge transfer between sub-cells via efficient carrier recombination at the RJ, which electrically connects the two cells. Acting as a sacrificial layer, PEDOT:PSS temporarily prevents resistive SiOx formation and improves interface quality. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy confirm suppression of SiOx growth during HTL annealing. Moreover, the Cu-doped NiOx HTL fabrication method proves critical, where process optimization improves electrical contact. Combined with PEDOT:PSS interface engineering, these enhancements promote efficient recombination by tuning interfacial energy levels and increasing band bending at the RJ. As a result, tandem devices comprising an aluminum back-surface field p-type homojunction Si bottom cell and a p-i-n perovskite top cell achieve 21.95% power conversion efficiency and an 81.3% fill factor -among the highest reported for monolithic perovskite/Si tandem solar cells. English Springer | Korea Nano Technology Research Society Sacrificial layer concept interface engineering for robust, lossless monolithic integration of perovskite/Si tandem solar cells yielding high fill factor of 0.813 Article 10.1186/s40580-025-00492-3 1 Nano Convergence, v.12, no.1 Nano Convergence 12 1 Y scie scopus kci 001497699700001 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Science & Technology - Other Topics Materials Science Physics Article HIGH-PERFORMANCE EFFICIENCY DESIGN TEMPERATURE PROGRESS Recombination junction Interface engineering Sacrificial layer PEDOT:PSS Band alignment Perovskite/Si tandem solar cell Monolithic integration