Direct Synthesis of CdSe Nanocrystals with Electroactive Ligands

We report the synthesis and characterization of cadmium selenide nanocrystals with electroactive ligands directly attached to the surface. The conventional surfactant-assisted synthesis yields nanocrystals with surfaces functionalized with insulating organic ligands. These insulating ligands act as a barrier for charge transport between nanocrystals. Electroactive (reducing/oxidizing) ligands like ferrocene and cobaltocene have potential for applications as photoexcited hole conductors and photoredox systems. Although ferrocene ligands anchored to the nanocrystal surface through insulating long-chain hydrocarbon spacers have previously been reported, this approach is limited because the charge transfer between nanocrystal and ferrocene is highly sensitive to their separation. We report here ferrocene directly bound to the inorganic core of the nanocrystal, and as a result the distance between the nanocrystals and the electroactive moiety is minimized.