FABRICATION OF QUANTUM DOT POLYMER COMPOSITES - PHOSPHINE-FUNCTIONALIZED BLOCK-COPOLYMERS AS PASSIVATING HOSTS FOR CADMIUM SELENIDE NANOCLUSTERS/

Nearly monodisperse CdSe nanoclusters, surface-passivated with a layer of trioctylphosphine and trioctylphosphine oxide, have been sequester ed within phosphine-containing domains in a diblock copolymer. A conve rgent approach to fabrication of these composites was adopted via inde pendent synthesis of nanoclusters and polymer. Diblock copolymers of p hosphine- or phosphine oxide-functionalized monomers and methyltetracy clododecene (MTD) were prepared by ring opening metathesis polymerizat ion using Mo alkylidene initiators. Nanoclusters were prepared by pyro lysis of CdMe(2) and Se=P(octyl)(3) in the presence of P(octyl)(3) and O=P(octyl)(3). An immediate and sustained increase in electronic pass ivation is found for nanoclusters incorporated into octylphosphine-con taining polymers. In contrast, nanoclusters in pure hydrocarbon or pho sphine oxide-containing polymers rapidly lose passivation. Films of na noclusters in a phosphine-containing polymer matrix were static cast f rom dilute solution. Under suitable conditions, the copolymers underwe nt microphase separation, and the metal chalcogenide clusters were pre dominantly sequestered within the phosphine-containing microdomains. T he original, highly uniform cluster size distribution was unaffected.