On 14 January, at the Nguyen Van Cu campus of VNUHCM–University of Science (HCMUS), the VNUHCM Project Evaluation Council convened to assess the research project: “Research on 2D Ag/TiO₂ heterostructures for low-concentration crystal violet detection via Raman spectroscopy,” led by Dr Tôn Nữ Quỳnh Trang. The Council concluded that the research successfully fulfilled all objectives and awarded the project an ‘Excellent’ rating.

The project focused on investigating Ag/TiO₂ heterostructures to develop high-sensitivity Surface-Enhanced Raman Scattering (SERS) sensors for detecting crystal violet (CV) at low concentrations. The primary research objectives involved elucidating the role of material structure, the distribution of silver nanoparticles, and the Ag/TiO₂ interaction mechanisms in relation to Raman signal amplification and sensor reusability. The research team successfully developed Ag@r-TNRs SERS substrates, where silver nanoparticles are precisely controlled and uniformly distributed across rutile TiO₂ nanorod arrays, creating a highly homogenous heterostructure.

The SERS performance of the material was optimised by adjusting the density of silver nanoparticles (AgNPs) to enhance Raman scattering signals. Crystal violet (CV) and chloramphenicol (CAP) molecules served as benchmarks to evaluate sensitivity and qualitative capabilities, demonstrating that Ag@r-TNRs substrates achieve exceptional sensitivity and precise qualitative identification. Beyond sensing functionality, the material exhibits effective self-cleaning and reusability due to the robust photocatalytic activity of TiO₂. Approximately 99% of CV degraded after 40 minutes of UV exposure, with a recovery efficiency of ~93% maintained over multiple cycles, confirming the stability of the material system.

Research findings indicate that the strategic integration of Ag/TiO₂ heterostructures, the optimisation of metal nanoparticle distribution, and the simultaneous exploitation of SERS and photocatalytic effects represent a highly effective approach for developing sensitive, sustainable Raman sensors. This project offers significant potential for the analysis of trace substances in food and the environment, carrying both high scientific value and practical utility.