Enhanced photoconversion efficiency in cesium-antimony-halide perovskite derivatives by tuning crystallographic dimensionality

•Structural dimensionality of all-inorganic antimony-based perovskite is tuned.•Conversion from 0D to 2D structure is achieved via compositional engineering.•Structural conversion enables dramatic external quantum efficiency boost to 62.5%.•Improved photoconversion efficiency is associated with charge transport enhancement.