Surface-State-Mediated Interfacial Hole Transfer Dynamics between CsPbBr<sub>3</sub> Perovskite Nanocrystals and Phenothiazine Redox Couple
Syed Akhil, V. G. Vasavi Dutt, Rahul Singh, Nimai Mishra
Abstract
Recently, cesium lead bromide (CsPbBr3) perovskite nanocrystals (PNCs) gained enormous attention in the designing of photocatalytic reactions because of their photocatalytic properties. However, the surface chemistry of nanocrystals is often ignored, which dictates the excited-state interactions of these semiconductor nanocrystals with charge shuttling redox-active molecules. In this work, we have explored the impact of CsPbBr3 perovskite nanocrystals with three different surface chemistries on the excited-state interactions with the standard hole acceptor phenothiazine molecule. From the steady state photoluminescence and lifetime decay measurements, we have calculated the photoinduced hole transfer (PHT). In the amine-free PNCs case, PHT is 6 times higher than for the conventional amine capped ligands. Using the lifetime fast component (τ1) rate constants, we have calculated the hole transfer constant (kht), which is 3.942 × 108 s–1, and it is 4 times higher in amine-free ligands compared with a conventional amine ligand system. These results highlight the impact of surface chemistry on the excited-state interactions of CsPbBr3 PNCs, and we conclude that amine-free PNCs could be an ideal candidate for photocatalytic reactions.