Quantifying and Comparing the Near-Field Enhancement, Photothermal Conversion, and Local Heating Performance of Plasmonic SiO2@Au Core-Shell Nanoparticles

摘要

In this work, the finite element method and two-temperature model were used to optimize the near electric field, photothermal conversion efficiency, and local heating of SiO2@Au core-shell nanoparticles (NPs) using water as the dispersion medium. The optimal core-shell sizes to achieve maximum near electric field enhancement, photothermal conversion efficiency, and local heating were 14nm/6nm, 8nm/3nm, and 24nm/12nm. The optimized core-shell ratio decreased with increasing the optimized wavelength for both near electric field and photothermal conversion optimizations. In the local heating or temperature increase, due to the existence of thermal boundary conductance, a temperature drop was observed between the electrons and the lattice, the electrons and the dielectrics, and the NP and the surrounding water. All these barriers and high absorption ability led to a temperature increase in the NP region. All optimized core-shell NPs achieved surface plasmon resonance for different targets. Comparison between different optimized targets with a normalized processing function indicated a smaller optimized core-shell size and core-shell ratio were obtained with a consideration of greater effect of the NP radius.