Colloidal synthesis of photoactive p-type spinel copper gallate nanocrystals

Herein we report the synthesis and characterization of spinel copper gallate (CuGa2O4) nanocrystals (NCs) with an average size of 3.7 nm via a heat-up colloidal reaction. CuGa2O4 NCs have a band gap of ~2.5 eV and a strong p-type character, in agreement with ab initio simulations. These NCs are demonstrated to be photoactive, generating a reproducible photocurrent under blue light irradiation when deposited as a thin film. The ability to adjust the Cu:Ga ratio within the NCs, and its effect on the optical and electronic properties of the NCs was also demonstrated.