Molecular nanoprobes for thermal imaging of photoexcited metallic nanoparticles
Résumé
Thermoplasmonic is considered one of the most recent and interesting research field. Today, one of the challenges is to measure and image the temperature generated around a single plasmonic nanostructure. Several approaches have been developed to address this issue. Here, we proposed a new approach based on the use of thermally polymérizable formulations such as molecular nano-probes to characterize the local heat profile in the vicinity of an isolated gold nanoparticle during its excitation. For this we developed a set of thermopolymérisables formulations, each one is characterized by a different and controlled polymerization temperature threshold threshold (Tth) witch can be adjusting by the weight percent of the initiator system. We studied the influence of various physical parameters on the extent of polymer around the nanoparticle. In particular, we show the possibility of imaging heat distribution with a spatial resolution of less than 40 nm, which corresponds to the extent of the polymer. We also used a range of thermopolymerisable solution characterized by different threshold temperatures (Tth) to measure the limit of thermal heating around the nanoparticle. The result shows that the temperature reached by the nanoparticle excited by 780 nm pulsed and focused laser (150 fs) exceeds 180 ° C. Studies are underway to obtain both the extinction and near-field thermal signature of an isolated gold nanoparticle at different wavelengths.