Probing perovskite photocatalysis. Interfacial electron transfer between CsPbBr3 and ferrocene redox couple

Interfacial charge transfer between a semiconductor nanocrystal and a molecular relay is an important step in nanomaterial photocatalysis. The ferrocene redox couple (Fc+/Fc0, E0 = −4.9 eV vs vacuum) has now been used as a model redox relay system to investigate photocatalytic properties of CsPbBr3 perovskite nanocrystals. The photocatalytic reduction of ferrocenium (Fc+) to ferrocene (Fc0) with CsPbBr3 nanocrystals was dictated by the surface interactions. Whereas a rapid quenching and subsequent recovery of CsPbBr3 emission is seen at low Fc+ concentrations, the quenched emission was sustained at higher Fc+ concentrations. The photoinduced interfacial electron transfer between CsPbBr3 and ferrocenium (Fc+) studied using transient absorption spectroscopy occurred with a rate constant of 1.64 × 1010 s–1. Better understanding of interfacial processes using redox probes can lead to the improvement in photocatalytic performance of perovskite nanocrystals.