Channeling Exciton Migration into Electron Transfer in Formamidinium Lead Bromide Perovskite Nanocrystal/Fullerene Composites

Hydrophobically capped nanocrystals of formamidinium lead bromide (FAPbBr(3)) perovskite (PNC) show bright and stable fluorescence in solution and thin-film states. When compared with isolated PNCs in a solution, closepacked PNCs in a thin film show extended fluorescence lifetime (ca. 4.2 mu s), which is due to hopping or migration of photogenerated excitons among PNCs. Both fluorescence quantum efficiency and lifetime decrease in a PNC thin film doped with fullerene (C-60), which is attributed to channeling of exciton migration into electron transfer to C-60. On the other hand, quenching of fluorescence intensity of a PNC solution is not accompanied by any change in fluorescence lifetime, indicating static electron transfer to C-60 adsorbed onto the hydrophobic surface of individual PNCs. Exciton migration among close-packed PNCs and electron transfer to C-60 places C-60-doped PNC thin films among cost-effective antenna systems for solar cells.