Enhanced photodesorption from near- and mid-infrared plasmonic nanocrystal thin films

The authors show that the desorption rate of two model molecules, indole and benzoic acid, from thin films of indium tin oxide nanocrystals supporting near-and mid-infrared (0.33-0.48 eV) localized surface plasmon resonances (LSPRs) is enhanced by as much as 60% upon illumination with broadband infrared light. The desorption rate increases linearly with light intensity. No increase in the desorption rate is detected for undoped In2O3 nanocrystal thin films or when photons resonant with the LSPR are blocked. The authors study the desorption rate enhancement as a function of illumination intensity, LSPR energy, and isotopic substitution. Importantly, the authors demonstrate the accelerated desorption via in-coupling of light to LSPRs with energies well within the mid-infrared. Their work opens the door to using these low energy photons as choreographers of chemical processes and sets the stage for future mechanistic studies. Published by the AVS.