Chemical Engineering of Heterojunction SERS Substrates: Emerging Tools for Disease Diagnosis and Health Monitoring

Disease diagnosis and health monitoring are crucial for safeguarding human health. However, environmental factors significantly threaten human health, such as water pollution and food safety issues, necessitating rigorous monitoring systems and biomedical solutions. Serving as a powerful detection technique, surface-enhanced Raman scattering (SERS) spectroscopy is deeply combined with environmental and biomedical detection due to its high selectivity and sensitivity. Among various SERS substrates, heterojunction structures are practical and promising due to their outstanding optical and electrical properties. This review outlines recent advancements in heterojunction SERS substrates with the classification by the components, including the semiconductor-semiconductor (S-S) and semiconductor-metal (S-M). The synthesis strategy, enhancement mechanism and applications of the various emerging heterojunctions are summarized carefully, where the applications span environmental monitoring, food safety, and biomedical detection. Despite progress, challenges remain in optimizing synthesis methods, exploring new material combinations to further boost SERS performance, and refining functionality for practical application.