  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.
