Photoactive p-Type Spinel CuGa <sub>2</sub> O <sub>4</sub> Nanocrystals
Owen Kendall, Lesly V. Meléndez, Jiawen Ren, Samantha Prabath Ratnayake, Billy J. Murdoch, Edwin Mayes, Joel van Embden, Daniel E. Gómez, Arrigo Calzolari, Enrico Della Gaspera
Abstract
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.