Research Highlights

Research Highlights

        Semiconducting plasmonic nanostructures have emerged as potential candidates for finding relevance in photodetector-based industry, plasmonic photovoltaic device, nanomedicine, chemical nanosensing, and photothermal therapy. Herein, our group has demonstrated ultrafast plasmon dynamics of the Cu2-xS nanocrystals in NIR region. Optical studies confirmed well defined localized surface plasmon resonance (LSPR) absorbance band from near-infrared to mid-infrared arising due to p-type hole vacancy in the doped semiconductor. Hole-hole, hole-phonon and phonon-phonon scattering time constants have been found to be varying depending on composition (copper to sulphur ratio) and excitation wavelength. At moderate pump power hole−phonon relaxation time constant has been observed to be in the range of 240−440 fs for Cu2−xS NCs depending upon pump wavelengths (400, 800 nm). From the ultrafast transient data, the hole−phonon coupling constant (G) determined for Cu2−xS NCs at different excitation wavelengths is also found to be one order lower than the metallic system. We have proposed a new mechanistic scheme for hot carrier relaxation dynamics, in accordance with the two-temperature model as reported in literature for plasmon dynamics. (10.1021/acs.jpcc.9b10043)