Luminescent sensors based on quantum dot–molecule conjugates

Semiconductor quantum dots (QDs) are inorganic nanoparticles that exhibit unique size-dependent optical and electronic properties; in particular, they are strongly luminescent. Their surface can be chemically modified, by either covalent or non-covalent approaches, in order to interface them with molecular units endowed with specific physical and chemical properties. Photoinduced electron- and energy-transfer processes between quantum dots and attached molecular species offer versatile strategies to modulate the photophysical properties of these nanoassemblies in response to a chemical stimulation. Hence, QD-molecule conjugates are appealing platforms for developing luminescent sensors according to a modular design. In this review we discuss the principles underlying the rational construction of this kind of multicomponent species, and we illustrate selected examples of luminescent QD-based sensors taken from the recent literature.