Metal-Free Peptide Semiconductor-Enhanced Raman Scattering.

There is a growing demand for sustainable and safe materials in developing technological systems and devices, including those that enhance Raman scattering. Organic (bio) materials based on simple peptides are one class of such materials. This study investigates self-assembled semiconducting peptides as metal-free substrates for surface-enhanced Raman scattering. Our results reveal significant variations in Raman enhancement factors, spanning up to 2 orders of magnitude. We examined specific Raman enhancement selection rules related to the energy levels and structural configurations of the probe molecules. The effectiveness of these rules underscores the importance of strong molecule-peptide coupling and efficient charge transfer for achieving optimal Raman enhancement factors. These insights offer a foundational understanding of peptide-molecule interactions and the underlying chemical mechanisms driving Raman enhancement, highlighting the potential of organic semiconductor-based materials as highly effective platforms for enhancing Raman scattering in chemical sensing applications.