Photoactivated CdSe Nanocrystals as Nanosensors for Gases

The photoluminescence (PL) of high-quality CdSe nanocrystals (NCs) incorporated into polymer thin films was found to respond reversibly and rapidly to environmental changes upon photoradiation above their absorption onset. The PL of the NCs may be dramatically enhanced or diminished depending on the properties of the gases. Photostimulation was found to be necessary for the response, which likely makes the original dense-ligands monolayer on the surface of the NCs permeable to gases by the activation of the vibration modes of the NC lattice through photon−phonon coupling.