Scalable Solution‐Processed Hybrid Electron Transport Layers for Efficient All‐Perovskite Tandem Solar Modules

Abstract

All‐perovskite tandem solar cells offer the potential to surpass the Shockley–Queisser (SQ) limit efficiency of single‐junction solar cells while maintaining the advantages of low‐cost and high‐productivity solution processing. However, scalable solution processing of electron transport layer (ETL) in p‐i‐n structured perovskite solar subcells remains challenging due to the rough perovskite film surface and energy level mismatch between ETL and perovskites. Here, scalable solution processing of hybrid fullerenes (HF) with blade‐coating on both wide‐bandgap (≈1.80 eV) and narrow‐bandgap (≈1.25 eV) perovskite films in all‐perovskite tandem solar modules is developed. The HF, comprising a mixture of fullerene (C60), phenyl C61 butyric acid methyl ester, and indene‐C60 bisadduct, exhibits improved conductivity, superior energy level alignment with both wide‐ and narrow‐bandgap perovskites, and reduced interfacial nonradiative recombination when compared to the conventional thermal‐evaporated C60. With scalable solution‐processed HF as the ETLs, the all‐perovskite tandem solar modules achieve a champion power conversion efficiency of 23.3% (aperture area = 20.25 cm2). This study paves the way to all‐solution processing of low‐cost and high‐efficiency all‐perovskite tandem solar modules in the future.

Narrow Bandgap Metal Halide Perovskites for All-Perovskite Tandem Photovoltaics

“…For example, the material interdiffusion between subcells and the reaction of halides and metal electrodes at the interconnecting areas of the modules has been a long-standing issue that raises severe loss of the device’s stability. , Although some chemically inactive barrier materials can, to some extent, suppress the material interdiffusion in the module, , it is generally accompanied by a reduction in the geometric FF of the modules due to the increased dead area. In general, the studies on the modularization of all-perovskite tandems are very limited, ,,, with the leading PCEs of no higher than 24%, lagging far behind the lab-based small-area cells. This suggests the pressing necessity for the further development of both large-area deposition methods and modularization technologies.…”

Annual research review of perovskite solar cells in 2023

“…Some other strategies were also developed to improve the performance of subcells and TSCs, such as surface treatment, addition of additives into the PVK precursors, and modification of the charge transport layers [202,[219][220][221][222][223]. In addition to these strategies for improving the PCE, tandem solar modules and strategies to reduce cost were also reported [224][225][226]. were also fabricated [192].…”