Role of Solvent in Electron‐Phonon Relaxation Dynamics in Core‐Shell Au−SiO₂ Nanoparticles

Abstract

Relaxation dynamics of plasmons in AuÀ SiO 2 core-shell nanoparticles have been followed by femtosecond pump-probe technique. The effect of excitation pump energy and surrounding medium on the time constants associated with the hot electron relaxation has been elucidated. A gradual increase in the electron-phonon relaxation time with pump energy is observed and can be attributed to the higher perturbation of the electron distribution in AuNPs at higher pump energy.Variation in time constants for the electron-phonon relaxation in different solvents is rationalized on the basis of their thermal conductivities, which govern the rate of dissipation of heat of photoexcited electrons in the nanoparticles. On the other hand, phonon-phonon relaxation is found to be much less effective than electron-phonon relaxation for the dissipation of energy of the excited electron and the time constants associated with it remain unaffected by thermal conductivity of the solvent.

Nonlinear Propagation of Laser Light in Plasmonic Nanocomposites

“…[ 71 ] Another factor that influences thermal transport dynamics is the environment of the particles, which can be altered by oxidized interfaces, [ 72 ] surface ligands, [ 69 ] or even due to solvent's thermal conductivity in soft matter systems. [ 73 ]…”

Photoluminescent Silica Nanostructures and Nanohybrids

“…[32,35,36] In fact, SiO 2 acts as protecting shell for many functional materials. [32,[35][36][37] Furthermore, SiO 2 NPs are biocompatible and hence can scaffold biological molecules. Increased photostability of dye molecules inside host SiO 2 matrix provides an additional advantage.…”

“…High thermal resistivity and chemical inertness provide chemical and structural stability to SiO 2 NPs in electronic, optical and optoelectronic devices [32,35,36] . In fact, SiO 2 acts as protecting shell for many functional materials [32,35–37] . Furthermore, SiO 2 NPs are biocompatible and hence can scaffold biological molecules.…”

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