Photoluminescence Switching of CdSe/ZnS Quantum Dots Toward Sensing Applications Triggered by Thermoresponsive Poly(<i>N</i>-Isopropylacrylamide) Films on Plasmonic Gold Surfaces

A route for the facile and modular assembly of a plasmonic/photonic structure was developed based on the covalent attachment of a thermoresponsive polymer film with a few nanometers thickness between a gold substrate and CdSe/ZnS quantum dot nanoemitters. The fast and reversible photoluminescence (PL) switching of the quantum dots upon passage of the polymer’s lower critical solution temperature regime (around 30 °C) confirmed the excellent fatigue resistance of the nanometer-thick film, featuring PL enhancement factors of up to 3. The modularity of the preparation steps guarantees precise tuning of the film thickness on the nanometer scale and, thus, significant improvement to control the interplay of plasmonic/photonic substructures that dictates the PL switching of immobilized nanoemitters for optoelectronic and sensing applications.