On the temperature stability of gold nanorods: comparison between thermal and ultrafast laser-induced heating

Abstract

The response of gold nanorods to both thermal and ultrafast laser-induced heating has been examined. The thermal heating experiments show structural changes that occur on timescales ranging from hours to days. At the highest temperature examined (250 °C) the nanorods are transformed into spheres within an hour. On the other hand, no structural changes are observed in the laser-induced heating experiments up to temperatures of 700 ± 50 °C. This is attributed to thermal diffusion in the laser experiments. Measurements of the period of the extensional mode of the nanorods using time-resolved spectroscopy show a significant softening at high pump laser powers. However, the decrease in the period is less than expected from bulk Young’s modulus vs. temperature data.