PbBr-based layered perovskite organic–inorganic superlattice having hole-transporting carbazole chromophore in organic layer

Oriented thin films of lead bromide-based layered perovskite having an organic–inorganic superlattice structure, which is combined with a lead bromide semiconductor layer and an organic layer of carbazole-linked ammonium molecules, were successfully prepared by spin-coating from dimethylformamide solution in which stoichiometric amounts of PbBr2 and carbazole-linked ammonium bromides were dissolved. The thin films exhibited sharp exciton absorption around 400 nm which is characteristic of PbBr-based layered perovskite in addition to absorptions due to carbazole chromophore peaking around 350 and 300 nm. X-ray diffraction measurement demonstrated that the layer structure was oriented parallel to the film plane: the spin-coated films exhibited only (0 0 n) reflections, where c-axis is in the stacking direction of the layer structure.