Unraveling the Lattice Matching Effect in Surface Phase Junctions for Interfacial Charge Separation

Exquisite control over the interface structure is highly desired for the successful fabrication of a semiconductor heterojunction, which has been confirmed to effectively promote charge separation and transfer. However, the influences of the interface microstructure in the heterojunction on the charge separation and transfer efficiency are still unclear. Herein, taking the TiO2 heterophase junction (A/R) between anatase and rutile phases and the TiO2 homophase junction (Rs/R) between large rutile rodlike particles and small rutile nanoparticles (∼20 nm) as a prototypical model, it is found that the lattice match at the interface is a key factor determining the charge separation and transfer efficiency and the photocatalytic activity. As compared with A/R, the atomically smooth interface with a highly matched lattice in Rs/R leads to a less-defective and abrupt interface and provides a smooth interfacial charge separation and transfer path, leading to improved charge separation and transfer efficiency and a great enhancement in photocatalytic activity. This study provides a novel insight into optimizing the heterojunction structure by designing a highly matched lattice interface between two components.