Back Cover: Halide Perovskite Single Crystals and Nanocrystal Films As Electron Donor‐Acceptor Heterojunctions (angew. Chem. Int. Ed. 4/2023)

The emission color and bandgap of halide perovskites are routinely tuned by halide mixing or quantum confinement. In their Communication (e202215947), Vasudevanpillai Biju and co-workers demonstrate selective exciton and carrier recombination in donor–acceptor bandgap engineered halide perovskite single crystals or nanocrystal films to show color tuning at desired locations. By real-time stitching of a narrow bandgap iodide domain in a wide bandgap microrod, microplate or nanocrystal sample, excitons and carriers are quantitatively transferred from the green-emitting bromide regions to the red-emitting iodide domain.