Kesterite tech news
Researchers led by Scientia Professor Xiaojing Hao and Dr. Kaiwen Sun at the University of New South Wales (UNSW) published a study in Advanced Materials on September 29, 2026, detailing a bilayer composition--modulated sulfurization (BCMS) architecture to resolve severe open--circuit voltage deficits in wide--bandgap kesterite (CZTS) solar cells. By implementing a pre--stabilized copper--rich bottom layer paired with a copper--poor upper layer, the technique precisely governs copper redistribution during sulfurization, suppressing the formation of detrimental Cu2SnS3 intermediate phases and transitioning crystallization from surface--dominated growth into a synchronized process across the absorber film. The resulting device achieved an 11.05% power conversion efficiency and an open--circuit voltage of 747.64 mV, representing the lowest voltage deficit reported to date for solution--processed wide--bandgap (>1.5 eV) CZTS cells and improving prospects for low--cost, earth--abundant top cells in tandem photovoltaics.