Revealing CdSe Quantum Dots Plasmonics Confined in Au Nanotrenches by Thermoacoustic Spectroscopy

Abstract

In this work, the influence of Au plasmonics on the thermoacoustic (TA) response of integrated thiol-linked CdSe quantum dot-Au nanotrench structures is demonstrated. The TA measurement technique uses a modulated light beam illuminating the sample placed into the air-filled cell and measures the temperature oscillation in the sample resulting from the light absorption. The intermittent heat generates an acoustic signal in the cell that is detected by a microphone. We observed an enhanced acoustic signal with increased light absorption. The enhancement is correlated with the plasmonic absorption by the Au grating layers. The signal is even more enhanced in two well-defined spectral bands peaking at about 400 and 490 nm due to CdSe QDs. The approach presented here can be extended in various fields employing light-to-heat conversion processes in hybrid metal–semiconductor nanomaterials and nanoplasmonic systems.