Flexible perovskite solar cells (PSCs) combine high efficiency with sustainability, making them a hot spot in green energy and a promising candidate for large-scale industrial production ^[1][2]. While Al foil offers excellent moisture and oxygen barrier properties, high thermal tolerance, and mechanical robustness, it’s the key point for the industrial roll-to-roll (R2R) production of lightweight, stable, and low-cost photovoltaic modules ^[3]. However, its surface roughness and interfacial incompatibility with perovskite layers cause challenges to device performance and upscaling.

This work addresses these challenges through a multi-faceted approach combining substrate engineering, interfacial modification, and scalable deposition techniques. Within the framework of the Horizon Europe Luminosity project, a successfully implemented barrier/ITO stack on Al foil, which serves as a smooth, conductive, and chemically compatible base for perovskite deposition, through the optimization of self-assembled monolayers (SAMs, e.g., MeO-4PACz) and interfacial passivation (e.g., PEACl), improved charge extraction and reduced hysteresis. The best-performing flexible PSCs on Al/barrier/ITO substrates with a semitransparent stack achieve a power conversion efficiency (PCE) of 14.64%, with low hysteresis and operational stability. Comparative studies on semitransparent Glass/ITO references with PCE up to 17.59% demonstrate the ongoing optimization pathway for Al-substrate devices. Furthermore, we report progress in laser patterning for monolithic module interconnection, a key step in R2R manufacturing.

This work demonstrates the feasibility of aluminum-substrate PSCs and highlights the crucial role of interface control in improving efficiency and stability. By combining material innovation with industrially relevant processing routes, we provide a viable path to commercializing high-performance, durable, and sustainable perovskite photovoltaic modules.

[1] S. Aftab, M.Z. Iqbal, S. Hussain, H.H. Hegazy, M.A. Saeed, Nano Energy (2023), 108249.

[2] L. Yang, J. Feng, Z. Liu, Y. Duan, S. Zhan, S. Yang, K. He, Y. Li, Y. Zhou, N. Yuan, Adv. Mater. 34 (2022) 2201681.

[3] A. Kumar, S. Rani, D. S. Ghosh, Sol. Energy Mater. Sol. Cells. 268 (2024) 112737.