Effect of Nanoparticle Size on Plasmonic Heat‐Driven Organic Transformation

Abstract Plasmonic nanomaterials have the potential to convert light to heat energy in an efficient and localized fashion. Here, we report the use of plasmonic heat from gold nanoparticles (AuNPs) in performing an important chemical transformation of pyrone to pyridinone in water. The yield obtained using plasmonic heat (∼75%) is comparable to that obtained from normal heating at ∼90 °C. Further, this photothermally driven organic reaction is used as a tool to study the effect of NP size on the practical utilization of the plasmonic heat dissipated. AuNPs in the size regime of 10–24 nm are found to be most efficient in driving the pyrone to pyridinone conversion, which is attributed to the dependence of absorption cross‐section and heat capacity on the NP size. The results obtained are validated using conventional plasmonically driven solar‐vapor generation experiments. Our study proves the suitability of a thermally driven organic reaction for qualitatively comparing the effect of various NP parameters on the chemical effectiveness of the plasmonic heat, which can be crucial in our efforts to understand the role of thermalization process in different plasmonically powered processes.