Interface-engineered charge separation at selective electron tunneling heterointerfaces

Abstract

The phenomena of charge/energy transfer commonly exist at most heterointerfaces. These processes vary with the change of the electronic structure at the interface, which leads to the diversity of device functionalities. Therefore, interface engineering is a powerful approach to control the charge/energy transfer behavior by modulating the interfacial electronic structure. On the basis of a novel ipsilateral selective electron tunneling (ISET) mechanism, we systematically investigated the charge transfer property at a semiconductor/graphene/photoactive material ternary interface. With acridine orange dye as the photoactive material, photoinduced electrons from the dye can directly tunnel across the TiO₂/graphene Schottky barrier into the conductive band of TiO₂, while the photoinduced holes were collected by graphene. These results demonstrate the capability of such an ISET-based ternary interface to achieve efficient charge transfer and separation, promising the fabrication of new types of photovoltaic and optoelectronic devices.