Measurements of the material properties of metal nanoparticles by time-resolved spectroscopy

An important aim of nanoparticle research is to understand how the properties of materials depend on their size and shape. In this Invited Article I describe how time-resolved spectroscopy can be used to measure physical properties of nanometre sized objects such as the characteristic time scales for electron - phonon coupling and heat dissipation, and their elastic moduli. The electron - phonon coupling and heat dissipation measurements are important for applications of particles that involve conduction of heat or electricity. On the other hand, the elastic moduli studies provide fundamental information about the properties of nanomaterials. The results of these experiments show that nanometre sized particles can have very different properties compared to the corresponding bulk material. For example, we have recently shown that gold nanorods produced by wet chemical methods have much smaller elastic moduli ( an 18% decrease in Young's modulus) compared to bulk gold.