On May 29, 2026, Marjan Monshi, a doctoral student at the Institute of Materials Science, defended her doctoral dissertation “Graphene-Metal Hybrid Plasmonic Structures: Synthesis, Multi-Spectroscopic Characterization, and Stable Analyte Detection” in the field of Natural Sciences, Physics.
The dissertation examines the design of two distinct metal-based Surface-Enhanced Raman Scattering (SERS) platforms engineered for highly stable, trace-level molecular detection: a nickel-core encapsulated architecture for ultraviolet (UV) response, and a graphene-overlayered silver array for visible spectrum plasmonic response. For the metal-encapsulated graphene shell architecture, the research established a novel multi-spectroscopic framework, integrating Raman, UV-Vis-nIR, and transient absorption spectroscopy (TAS), to accurately assess the structural quality of the disordered shells. By utilizing these advanced hybrid designs, the study demonstrated that novel nickel-encapsulated graphitic shells can preserve the plasmonic activity of a highly reactive metallic core for over two years, successfully enabling the resonant detection of biomolecules like adenine in the ultraviolet range at 325 nm.
Furthermore, the dissertation investigated the integration of a protective monolayer graphene shield onto resonant silver nanoparticle arrays. A year-long longitudinal study revealed that this graphene overlayer significantly extends the operational lifetime of the 2-naphthalenethiol (2NT) molecule signature from mere weeks to over a year, achieving approximately 30% analyte signal retention after 344 days.
This research was conducted at the Institute of Materials Science at Kaunas University of Technology, with external assistance from the Center for Physical Sciences and Technology in Vilnius, the National Institute for Materials Science in Japan, and the PCAM network at the Mads Clausen Institute, University of Southern Denmark.
