Many desirable solar fuel forming reactions require multiple reduction and oxidation steps. Thus solar-to-fuel conversion devices require not only efficient catalysts to accelerate the reactions, but also novel schemes to accumulate multiple electrons/holes needed in the catalytic centers through sequential single photon absorption and single electron transfer events in light harvesting components. Unlike molecular chromophores, semiconductor nanocrystals can generate and accumulate multiple excitons through either direct multi-exciton generation by one high energy photon or multiple photon absorption. Furthermore, in quantum confined semiconductor nanocrystals (quantum dots or nanorods), the confinement of electrons and holes lead to enhanced amplitudes of their wave functions at the surface, enabling direct and efficient dissociation of excitons by interfacial electron or hole transfer to surface adsorbed acceptors or catalysts.Unfortunately, the small volume of quantum confined nanocrystals also enhances exciton Auger recombination process, wherein an electron-hole pair (exciton) nonradiatively recombines by transferring its energy to a third carrier. In this presenation, we will discuss our recent study of the dynamics of multiple exciton dissociation and multiple electron transfer to catalysts as well as the competing Auger recombination and charge recombination processes in model photocatalytic heterostructures (such as quantum dot-Pt and nanorod-Pt).

Photoinduced multiple electron transfer from quantum confined nanostructures to catalysts

247th National Meeting (2014)

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