Metal and semiconductor nanomaterials have shown many promising applications in photocatalysis, photovoltaics and light emitting devices. Because many of these applications require the transfer of charges in and out of metal and semiconductor nanoparticles, these processes have been a subject of intense studies in recent years. In this talk, I will high light two novel features of interfacial charge transfer from nanomaterials that differ from their bulk counterparts.<br/>In quantum confined semiconductor nanomaterials, such as quantum dots, nanorods and nanoplatelets, the quantum confinement effect leads to unique electronic structures that differ significantly from those of bulk semiconductor and molecules, resulting in distinct interfacial charge transfer properties. We show that exciton dissociation by electron transfer from these materials to molecular acceptors follows the Auger assisted electron transfer model in which the transfer of the electron can be coupled to the excitation of the hole, circumventing the unfavorable Franck–Condon overlap in the Marcus inverted regime. We believe that this is a general feature for charge transfer from exciton states of low dimensional nanomaterials.<br/>Plasmon-induced hot-electron transfer from metal nanostructures is a potential new paradigm for solar energy conversion; however, the reported efficiencies of devices based on this concept are often low because of the loss of hot electrons via ultrafast electron-electron scattering. We show that by decreasing the size of plasmonic nanocrystals, plasmon induced hot electron transfer efficiency from plasmonic nanocrystals to semiconductor acceptors can be enhanced through two novel processes in plasmonic metal/semiconductor nanoheterostructures. First, plasmon-induced interfacial charge-transfer transition (PICTT) can lead to the direct excitation of an electron from the metal to the strongly coupled semiconductor domain to enable efficient hot electron transfer. Furthermore, enhanced plasmon surface damping in small plasmonic nanocrystals increases the hot electron distribution and interfacial electron transfer coupling strength, which also enhance the plasmon induced hot electron transfer efficiency.

Novel features of interfacial electron transfer from metal and semiconductor nanoparticles

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ACS Fall 2022

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