Researchers have developed a molecular coordination strategy to produce uniform kesterite solar films over larger surface areas, according to a study published in Nature Materials. The technique regulates metal–organic coordination within precursor solutions to suppress cross-linked networks, removing a long-standing obstacle in scaling up thin-film photovoltaics.
Kesterite, or Cu2ZnSn(S,Se)4, consists of earth-abundant and non-toxic elements, making it an attractive alternative for low-cost solar energy. Although solution-based processing has enabled rapid performance improvements in laboratory-scale devices, scaling up to larger modules has proven difficult. Complex coordination networks in precursor solutions often prevent uniform solvent removal, selenization, and crystallization over large surfaces.
Module Efficiencies
To address the issue, the research team implemented molecular-level control over metal–organic coordination. This approach suppressed unwanted cross-linked precursor networks, promoting even solvent evaporation and uniform crystallization across the absorber layer. Using this coordination-controlled method, the team successfully blade-coated homogeneous kesterite absorber films over areas of 10 square centimeters.
The resulting devices achieved certified power conversion efficiencies of 14.2% for 1 square centimeter cells and 13.0% for 10.5 square centimeter solar modules. The authors noted that these molecular insights into solution chemistry offer a low-cost, scalable pathway toward industrial manufacturing of kesterite solar panels.
Study Details
The research paper was published on August 3, 2026, following submission in December 2025 and acceptance in July 2026. Co-lead authors Bowen Zhang, Menghan Jiao, Xiao Xu, and Jiazheng Zhou led the work alongside corresponding authors Jiangjian Shi and Qingbo Meng at the Chinese Academy of Sciences. The project received support from the National Key R&D Program of China, the National Natural Science Foundation of China, and the Zhejiang Provincial Natural Science Foundation, with technical assistance from the High Energy Photon Source beamline.
