Photochemical Synthesis of Selenium Nanospheres of Tunable Size and Colloidal Stability with Simple Diketones.

Temporal and spatial segregations are two fundamental requirements for the successful synthesis of nanoparticles (NPs). To obtain colloidally stable selenium nanospheres (SeNSs), surfactants or polymers are generally needed as structure-directing agents or stabilizers in the reduction approaches for SeNP synthesis. The addition of such chemicals sacrifices the purity of the obtained SeNPs and, therefore, is detrimental to the applications. Here, for the first time, we report that low-molecular weight (less than six carbons) diketones are excellent photoreductants for green and tunable synthesis of SeNPs, owing to their merits in temporal and spatial control. With simple diketones as the photoreductants, the resultant SeNPs were pure and colloidally stable with nice photoelectronic properties. This finding not only provides a useful strategy for the synthesis of SeNPs but also might be a milestone in the development of ketone photochemistry.