Tailoring charge transfer in perovskite quantum dots/black phosphorus nanosheets photocatalyst via aromatic molecules

Typical ligands like long-chain alkane or siloxane are not in favor of charge transfer due to their insulating nature, which hinders perovskites' applications in photovoltaic devices or photocatalysis. Herein, short-chain conductive aromatic molecules benzylamine (BZA) and benzoic acid (BA) were employed to passivate CsPbBr3 QDs and to serve as charge mediators for the first time in CsPbBr3 QDs/black phosphorus nanosheets (BP NSs) for photocatalytic CO2 reduction. The influences of various ligands on interfacial charge transport were further investigated via several means of analyses like electrochemical measurement and photoluminescence (PL) decay. And it's verified that short-chain aromatic molecules show much more potential as charge mediators than long-chain alkane or siloxane compounds. The electron consumption rate of composite photocatalyst bridged by aromatic mediators is 76.6 µmol g−1 h−1, which is almost 1-fold and 4-fold compared with that of long-chain alkane ligands group and siloxane ligands group, respectively.