Kesterite tech news
Researchers from Central South University, the Chinese Academy of Sciences, and the University of Melbourne published a study in Applied Physics Letters revealing the physical mechanism driving storage--induced efficiency gains in kesterite (CZTSSe) thin--film solar cells. By tracking sodium (Na) ion migration over a 90--day dark, dry storage period, the team identified that extrinsic Na ions migrate along grain boundaries to the absorber surface. This migration passivates deep--level tin--related defects, optimizes heterojunction band alignment, and enhances carrier transport, spontaneously increasing device power conversion efficiency from 13.02% to 14.37%. The discovery provides actionable insights into post--processing and defect management for commercializing earth--abundant, non--toxic kesterite photovoltaics.