Pyroelectrically Driven Charge Transfer and its Advantages on SERS and Self-Cleaning Property

Abstract

The fabrication of reusable SERS substrates with sensitivity at the single-molecule level remains challenging but promising. Herein, a composite surface-enhanced Raman scattering (SERS) substrate is proposed that includes Ag nanoparticle (Ag NPs) /Graphene/BaTiO₃ (Ag/G/BTO) from a chemical enhancement perspective. The pyroelectric field generated by BaTiO₃ drives the charge transfer between the SERS substrate and molecules, achieving a significant improvement in the SERS performance and self-cleaning properties. The SERS signals of rhodamine 6G (R6G) molecules are further amplified up to 70-fold. Thus, the detection limit is reduced by three orders of magnitude in this study, reaching 10⁻¹⁴ m after applying a pyroelectric field. In addition, the substrate exhibits a higher degradation efficiency than previous self-cleaning SERS substrates because of the outstanding catalytic properties of BaTiO₃. Target molecules are degraded effectively after several temperature cycles. A detailed mechanism analysis of pyroelectric SERS is conducted based on theoretical simulations and experimental results. This study is considered to deepen the understanding of SERS mechanisms and boost the application of SERS technology.