Photothermal Stability and Hot Carrier Dynamics of Gold Nanostructures

Anisotropic shapes of gold nanoparticles are prepared using a modified seed method in the presence of silver ions or clusters in order to study the photo-thermal stabilities and the dynamics of the hot carriers induced by femtosecond laser pulses.It has been observed from studying their photostability to low-power UV irradiation (254 nm) at room temperature that, whereas spheres are very stable to photoirradiation, rods and prisms suffer from photocorrosion and finally dissolve completely with the production of Au(III) ions. Although gold nanospheres are also stable towards thermal treatment, the decomposition of the gold nanorods into spherical nanoparticle aggregates is mechanistically different from the case of nanoprisms.In regards to the hot carrier dynamics, it is found that the phonon-phonon (ph-ph) coupling is much slower in dots than in rods and prisms while electron-phonon (e-ph) coupling is almost the same in these particles.