Raman thermometry of plasmonic nanoparticles

Device miniaturization in microelectronics, photonics, and biomedical engineering has pushed material dimensions into the nanometer regime, where physical and chemical properties often differ substantially from those of bulk materials. Plasmonic nanoparticles are a prominent example, capable of efficiently converting optical energy into heat under light excitation. This photothermal effect has important applications such as targeted cancer therapy, photothermal catalysis, and solar-driven water evaporation. However, accurate temperature measurement at the nanoscale remains a major challenge, as conventional thermometry lacks the spatial resolution and accessibility required for nanostructured or confined environments. This thesis investigates Raman thermometry as a non-contact, high-resolution method for probing temperature in plasmonic nanosystems. Temperature-dependent Raman peak shifts in thin films of α- and β-phase copper phthalocyanine (CuPc) are employed as robust local thermometric probes. These CuPc layers are integrated with individual plasmonic nanoparticles and nanoparticle arrays, which are optically excited to induce photothermal heating while simultaneously enabling Raman-based temperature readout. Using this approach, the collective temperature of irradiated nanoparticle arrays is quantified, and spatially resolved photothermal effects in single nanostructures—such as silver nanodisks and gold nanorods—are reconstructed. The findings demonstrate that Raman peak-shift thermometry provides a reliable and versatile strategy for nanoscale temperature measurement in plasmonic environments, offering important insights for the design of photothermal nanodevices and their applications in energy conversion, catalysis, and biomedicine.