Semiconductor Quantum Dots as Photocatalysts for Controlled Light-Mediated Radical Polymerization.

Light-mediated radical polymerization has benefited from the rapid development of photoredox catalysts and offers many exceptional advantages over traditional thermal polymerizations. Nevertheless, the majority of the work relies on molecular photoredox catalysts or expensive transition metals. We exploited the capability of semiconductor quantum dots (QD) as a new type of catalyst for the radical polymerization that can harness natural sunlight. Polymerizations of (meth)acrylates, styrene, and construction of block copolymers were demonstrated, together with temporal control of the polymerization by the light source. Photoluminescence experiments revealed that the reduction of alkyl bromide initiator by photoexcited QD is the key to this light-mediated radical polymerization.