Photoactive p-Type Spinel CuGa 2 O 4 Nanocrystals.

Herein we report the synthesis and characterization of spinel copper gallate (CuGa 2 O 4 ) nanocrystals (NCs) with an average size of 3.7 nm via a heat-up colloidal reaction. CuGa 2 O 4 NCs have a band gap of ∼2.5 eV and marked p-type character, in agreement with ab initio simulations. These novel NCs are demonstrated to be photoactive, generating a clear and reproducible photocurrent under blue light irradiation when deposited as thin films. Crucially, the ability to adjust the Cu/Ga ratio within the NCs, and the effect of this on the optical and electronic properties of the NCs, was also demonstrated. These results position CuGa 2 O 4 NCs as a novel material for optoelectronic applications, including hole transport and light harvesting.