A Rapid Flux-Assisted Synthetic Approach Towards the Bandgap Engineering of Layered Perovskites

The metal-halide-exchanged (CuCl)LaM2O7 and (CuCl)Ca2M3O10 (M = Nb, Ta) are obtained in high purity from the parent layered perovskite hosts using a rapid synthetic approach in molten alkali-nitrate or alkali-bisulfate fluxes at 300−400 °C in only 1 −2 h. The insertion of CuCl layers also introduces new higher-energy valence bands into the electronic structure of the perovskite hosts and lowers their band gap sizes by 1.0−1.4 eV into the visible region, shown in TOC Figure. Thus, the CuCl layers are shown to modify both the atomic and electronic structures and suggest their potential use in visible-light sensitization of photocatalysts.