Function-Customized Heterostructure for Boosting Semiconductor Surface-Enhanced Raman Scattering and Serving as a Multifunctional Platform

Constructing function-customized semiconductor heterostructures is an effective strategy for developing non-noble metal surface-enhanced Raman scattering (SERS) matrixes and also provides potential opportunities for developing specific multifunctional platforms. Here, a 0D/2D TiO₂/Ti₃C₂ MXene heterojunction with hot electron excitation and high-efficiency carrier separation was successfully constructed for boosting semiconductor SERS. The enhancement factor of the SERS matrix is as high as 5.57 × 10⁹, which is currently the highest sensitivity of semiconductor substrates. Theoretical calculations and experiments reveal the contribution of charge transfer mechanisms to SERS enhancement. High carrier utilization rate contributed by hot electron excitation of Ti₃C₂ and high carrier separation efficiency induced by interface heterostructure are together responsible for the observed huge SERS enhancement. Meaningfully, the TiO₂/Ti₃C₂ matrix can serve as a sensing platform for monitoring PPCP pollutants (pharmaceuticals and personal care products) in real environment and can also be used as a photocatalytic platform for their efficient degradation. This work provides an idea and perspective for developing ultrasensitive semiconductor SERS matrixes and also provides a guidance for developing specific multifunctional platforms, ultimately promoting practical application of SERS technology in its own and other fields.