Effect of TiO2 on Altering Direction of Interfacial Charge Transfer in a TiO2 -Ag-MPY-FePc System by SERS.

Interfacial charge transfer (CT) is of interest owing to its effect on the performance of molecular photovoltaic (PV) devices. The characteristics and structures of interfacial materials, such as TiO2 nanoparticles (NPs) in some solar cells, are employed to adjust the CT process. In this study, three kinds of interfacial systems, including a solar cell-like TiO2 -Ag- p-mercaptopyridine (MPY)- iron phthalocyanine (FePc) system, are compared to investigate the interfacial CT process using surface-enhanced Raman scattering (SERS) spectroscopy. The SERS results show the significance of TiO2 NPs in the system on altering the direction and path of the interfacial CT, which is closely associated with the CT enhancement contribution to SERS in such an interfacial system. SERS spectroscopy is expected to be a promising technique for the exploration and estimation of the interfacial CT behavior in PV devices, which may further extend the applications of SERS in the field of solar cells.