Investigation Of Charge Transfer At The Semiconductor-MBA-Au Nanorods Interface Based On SERS

As well known,besides of the resonances within the molecule itself,surface plasmon resonance?SPR?and charge transfer?CT?resonance are considered as the two most important sources of the huge signal enhancement in surface enhanced Raman scattering?SERS?.The SPR and CT are often treated as independently contributing to the overall SERS effect,and none of the related studies have revealed the contribution of SPR towards CT.In this article,we have studied it in the following two parts:?1?Investigation of charge transfer at the Ti O₂–MBA–Au interface:SPR contributionIn this study,the CT at the interfaces between titanium dioxide?TiO₂?and gold?Au?is investigated by SERS spectroscopy probed by a sandwiched molecule4-mercaptobenzoic acid?4-MBA?.For the first time,the contribution of SPR to the CT in the assemblies is studied by tuning the surface plasmon absorption of the Au nanorods?NRs?.we propose a CT pathway in these semiconductor-molecule-metal assemblies,and the mechanism by which SPR contributes to the CT at the interfaces is discussed.This study has established a simple and effective way of studying the influence of SPR on interfacial CT by using SERS,which is beneficial for further investigations on interfacial charge transfers.?2?Investigation of interface charge transfer in ZnO-MBA-Au NRs based on ZnO of different morphologiesBy adjusting the morphology of ZnO nanoparticles and the aspect ratio of Au NRs,ZnO-MBA-Au NRs assembly systems with different modes were constructed.UV-vis characterized the change of SPR in Au NRs with the aspect ratio,and the change of Au SPR in different assemblies and the band gap of semiconductors.Based on this,the electron loss of Au NRs in different assembly systems was analyzed.Raman characterizations the interfacial CT in different assembly systems.Furthermore,the contribution of SPR to SERS and CT in the assembly system and the influence of ZnO morphology on the contribution of SPR were studied.This gives us a deeper understanding of the relationship between SPR and CT,which provides a further theoretical basis for the enhanced mechanism of SERS technology and provides guidance for the construction of a system with higher charge transfer degree.This is of great significance for the development of SERS and the preparation of efficient photoelectric devices and photocatalysts.