  Surface ligand exchange on all-inorganic perovskite nanocrystals of
composition CsPbBrI$_{2}$ reveals improved optoelectronic properties due to
strong interactions of the nanocrystal with mono-functionalized porphyrin
derivatives. The interaction is verified experimentally with an array of
spectroscopic measurements as well as computationally by exploiting density
functional theory calculations. The enhanced current efficiency is attributed
to a lowering of the charging energy by a factor of 2 to 3, which is determined
by combining electronic and optical measurements on a selection of ligands. The
coupled organic-inorganic nanostructures are successfully deployed in a light
emitting device with higher current efficacy and improved charge carrier
balance, magnifying the efficiency almost fivefold compared to the native
ligand.
