Multi-charge Transfer from Photodoped ITO Nanocrystals

Abstract

Metal oxide nanocrystals are emerging as extremely versatile material for addressing many of the current challenging demands of energy-conversion technology. Being able to exploit their full potential is not only an advantage but also a scientific and economic ambition for a more sustainable energy technology. In this direction, photodoping of metal oxide nanocrystals is a very notable process that allows accumulating multiple charge carriers per nanocrystals after light absorption. The reactivity of the photodoped electrons is currently the subject of an intense study. In this context, the possibility to efficiently extract the stored electrons could be beneficial for numerous processes, from photoconversion and sunlight energy storage, to photocatalysis and photoelectrochemistry. In this work we provide, via oxidative titration and optical spectroscopy, evidence for multi-electron transfer processes from photodoped Sn:In2O3 nanocrystals to a widely employed organic electron acceptor (F4TCNQ). The results of this study disclose the potential of photodoped electrons to drive chemical reactions involving more than one electron at a time.