Polymeric Layer-Mediated Redox Sensing System Containing Covalently Attached CdSe/ZnS Quantum Dots on Au Films

Reversible photoluminescence (PL) switching represents a highly demanded feature in sensors, optical/electronic devices, imaging and logic gates, etc. Utilizing a straightforward spin-coating-based sample fabrication procedure, we developed a gold-quantum dot (QD) hybrid system that revealed PL switching in response to redox processes. The PL switching of the system relies on a redox-responsive poly[N-isopropylacrylamide-co-vinylferrocene-co-methacryloyl benzophenone] nanometric thick spacer layer, through which the QDs were attached to a gold film. The designed hybrid system revealed a 2.3 ± 0.6-fold PL intensity switching factor arising from PL quenching upon oxidation of the spacer layer and PL recovery after reducing the layer. Notably, the behavior was both reversible and reproducible, judged by analysis of three samples and several applied redox processes. This study can open a window to further development of plasmonic-fluorophore switchable devices using stimuli-responsive polymeric spacers in particular for sensing and bio-sensing applications.