Electron Transfer from an Optically Pumped Polyhedral Perovskite Nanocrystal to Pristine Fullerene

Pristine fullerene (C-60), without an anchor group, can form a complex with 12-faceted dodecahedron CsPbBr3 perovskite nanocrystals (PNCs) owing to a greater number of binding facets of the latter. The PNC-fullerene hybrid with optically rich properties exhibits efficient photoinduced electron transfer (PET) from optically pumped PNCs to fullerene. While time-correlated single-photon counting deduced the intrinsic PET time scale (similar to 1.8 ns per quencher) utilizing photoluminescence lifetime quenching of the PNCs, the fluorescence correlation spectroscopy, on the other hand, determined the stability of the PNC-fullerene complex along with the associated time scale of the complexation reaction (tau(R) similar to 500 mu s). Complex formation assures an insignificant role of solvent diffusion in our bimolecular PET study. Considering the inherently complex nature of the PET reaction that cannot be explained by a Stern-Volmer analysis, we employed a stochastic model initially proposed by Tachiya to render insight into the PET mechanism, assuming fullerenes distributed on the PNC surface follow Poisson statics. The fast intrinsic PET time scale in the one-to-one PNC-fullerene hybrid points toward the fact that the dramatic improvement of efficiencies of the polyhedral PNC-based devices can become a reality.