Tunable electronic and optical properties of new two-dimensional CuCl/GaSe van der Waals heterostructures with the potential for photocatalysis applications

The construction of a heterojunction photocatalyst can enhance the absorption of visible light and reduce the recombination of electrons and holes, which greatly improves the photocatalytic performance, which is also a current research hotspot in the energy field. In this paper, the first-principles calculation method is used to systematically study the electronic structure and photocatalytic mechanism of the new CuCl/GaSe van der Waals (vdW) heterojunction. The main research contents are summarized as follows: CuCl/GaSe vdW heterojunction is a direct band gap semiconductor material with a lattice mismatch rate of less than 1.5%, and a stable structure. The band gap of the heterojunction is 1.143 e V, which corresponds to a wider visible light absorption range. And it shows direct energy band alignment. The photo-generated holes are transferred from the GaSe layer to the CuCl layer, while the electrons are on the contrary, indicating that the electrons and holes are well separated in space. All these indicate that the CuCl/GaSe vdW heterojunction has good photocatalytic performance and is a new type of photocatalytic material with excellent performance.