Piezoelectric modulated charge transfer in SERS substrate based on black phosphorous-graphene oxide/polyvinylidene fluoride

Electrical modulation is considered to be effective in improving the localized electromagnetic strength of surface enhanced Raman scattering substrates (E-SERS). In this field, polyvinylidene fluoride (PVDF) as a versatile piezoelectric matrix has been extensively employed to construct E-SERS substrates by combining with noble metals. However, there is nearly no exploration of the impact of the piezoelectric effect on the charge transfer within bare semiconductors, which will greatly expand the variety of E-SERS substrates. In this study, a novel semiconductor-based E-SERS substrate was developed by integrating black phosphorous (BP)-graphene oxide (GO) composite with a PVDF matrix. A significant SERS signal amplification was achieved when subjected to mechanical stress. Such amplification was owing to the improvement of charge transfer efficiency facilitated by the external force-triggered polarization charge, which was proved by the photocurrent test. The piezoelectric effect was verified to boost chemical enhancement and the semiconductor-based E-SERS substrate was capable of achieving high sensitivity.