Nature Communications paper Zehua Chen, Shuxia Tao, Geert Brocks and Peter Bobbert
Zehua Chen, Shuxia Tao, Geert Brocks and Peter Bobbert, collaborating in the CCER, got their work Unified theory for light-induced halide segregation in mixed halide perovskites published in Nature Communications (April 2021). In perovskites for photovoltaics the band gap can be tuned by mixing different halide ions, like iodine and bromine. Under illumination, however, the halide ions show an undesired segregation, leading to a low and a high bandgap phase. The unified theory of the authors is based on a minimization of the sum of a compositional and a photocarrier free energy. It explains various observed aspects of the segregation and provides clues for its suppression.