China's kesterite solar cell sets world record with 15.45% efficiency

Researchers at the Chinese Academy of Sciences (CAS) have set a new world record for kesterite solar cell efficiency, achieving 15.45% power conversion efficiency in tests, with an internationally certified third-party efficiency of 15.04%. This surpasses the previous record of 14.2% held by the same team earlier in 2024. Kesterite, a mineral composed of copper, zinc, tin, and sulfur (CZTS), is a promising material for next-generation thin-film solar cells due to its abundance, non-toxicity, and low production costs, offering advantages over CIGS compounds which face supply bottlenecks. The breakthrough was made by addressing the core challenge of uncontrollable metal ion migration within the solar cell lattice, which causes defects that reduce efficiency and stability. The CAS team developed a novel interphase using a lithium tin sulfide compound (Li₂SnS₃ or LTS) that modifies cation migration paths and balances copper and tin migration