Thermoplasmonics: Taking the heat out from plasmonic nanostructures
A major portion of the absorbed light energy is dissipated by plasmonic nanostructures in the form of heat - commonly referred to as local or plasmonic heating. This thermalization process forms the basis of various thermoplasmonic applications in both medical and energy sectors. Our group is interested in designing systems and strategies to efficiently utilize, quantify, and store this plasmonic heat.
Utilization: We use the plasmonic materials as nano-heaters for performing versatile and useful photothermal processes, such as polymerization, solar-vapor generation, organic reactions, and crystal-to-crystal transformation.
We are also interested in using thermally driven organic transformations as a tool to study the effect of nanoparticle parameters (such as size and shape) on the chemical effectiveness of the plasmonic heat (Scheme 2).
Quantification: Ability to quantify the plasmonic heat in a convenient way is essential to successfully regulate its impact on various plasmonic processes. Our group has used the process of thermochromism as a simple and reliable tool to quantify the practically usable thermoplasmonic heat close to the surface of nanostructures. A simple visual color change served as the read out for the heat generated. This unprecedented use of thermochromism in quantifying the thermalization process shows that the surface of gold nanorod arrays can heat up to ~250 °C within ~15 min of irradiation, which was independently validated with standard infra-red based thermometric imaging studies.
Representative publications: ChemNanoMat 2022, Chem. Mater. 2022.
Students in-charge: Radha Krishna Kashyap, Shreya Tyagi
