Structuring and Self-Assembly of Gold based Nanorods for High Temperature Raman Sensing

This thesis explores the potential of gold nanorods for enhanced sensing applications at elevated temperatures. By modulating their structure and composition, we aimed to optimize their plasmonic properties for Raman scattering enhancement. Through systematic investigations, we elucidated the mechanisms governing self-assembly dynamics and the influence of nanorod structure on SERS performance. We successfully synthesized gold nanorods with a silica shell containing mesopores, providing a versatile platform for further structural engineering. We explored the impact of supraparticle formation and interparticle distance on Raman signal enhancement, demonstrating that carefully optimized structures significantly boost SERS sensitivity. Additionally, we employed advanced electron microscopy techniques to investigate the formation of hotspots within these nanostructures, revealing the relationship between structural-electronic properties and SERS performance. To expand the applicability of gold nanorods to high-temperature Raman sensing, we introduced bimetallic nanorods composed of a gold core and a palladium shell. By controlling the shell thickness and composition, we achieved precise tuning of their plasmonic properties and thermal stability. Self-assembly of these bimetallic nanorods into supraparticles further enhanced their SERS performance, paving the way for novel high-temperature sensing applications. Overall, this thesis provides valuable insights into the structural engineering of gold nanorods for enhanced sensing applications. Our findings highlight the potential of these nanomaterials for developing advanced sensors capable of operating under challenging conditions.