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Si quantum dot (QD)-molecule hybrid systems have emerged as a popular architecture in many research fields due to the ability to select for the advantages conferred by the inorganic Si component and the organic sections. This perspective will focus on the optical properties of Si QDs, the parameters that affect Si QD photophysics or energy transfer in Si QD-molecule hybrid structures, and their resultant hybrid optoelectronic devices. Examples of recent applications that employ Si QD-molecule hybrid materials are presented. Finally, we discuss current issues involving basic structure–property relationships that need to be addressed for Si QDs and conclude with an outlook on the bright future of Si QD-molecule hybrid materials. 

Photon upconversion in systems incorporating inorganic quantum dots (QDs) is of great interest for applications in solar energy conversion, bioimaging, and photodynamic therapy. Achieving high up-conversion efficiency requires not only high-quality inorganic nanoparticles, but also precise control of their surface functional groups. Gas-phase surface functionalization provides a new pathway towards controlling the surface of small inorganic nanoparticles. In this contribution, we utilize a one-step low-temperature plasma technique for the synthesis and in-flight partial functionalization of silicon QDs with alkyl chains. The partially functionalized surface is then modified further with 9-vinylanthracene via thermal hydrosilylation resulting in the grafting of 9-ethylanthracene (9EA) groups. We have found that the minimum alkyl ligand density necessary for quantum dot solubility also gives the maximum upconversion quantum yield, reaching 17% for silicon QDs with Si-dodecyl chains and an average of 3 9EA molecules per particle.