Immobilization of quantum dots via conjugated self-assembled monolayers and their application as a light-controlled sensor for the detection of hydrogen peroxide.

A light-addressable gold electrode modified with CdS and FePt or with CdS@FePt nanoparticles via an interfacial dithiol linker layer is presented. XPS measurements reveal that trans-stilbenedithiol provides high-quality self-assembled monolayers compared to benzenedithiol and biphenyldithiol, in case they are formed at elevated temperatures. The CdS nanoparticles in good electrical contact with the electrode allow for current generation under illumination and appropriate polarization. FePt nanoparticles serve as catalytic sites for the reduction of hydrogen peroxide to water. Advantageously, both properties can be combined by the use of hybrid nanoparticles fixed on the electrode by means of the optimized stilbenedithiol layer. This allows a light-controlled analysis of different hydrogen peroxide concentrations.