Ligand-free CsPbBr3 with calliandra-like nanostructure for efficient artificial photosynthesis

Abstract

The low-efficiency CO2 uptake capacity and insufficient photogenerated exciton dissociation of current metal halide perovskite (MHP) nanocrystals with end-capping ligands extremely restrict their application in the field of artificial photosynthesis. Herein, we demonstrate that ligand-free CsPbBr3 with calliandra-like nanostructure (LF-CPB CL) can be synthesized easily through a ligand-free seed-assisted dissolution-recrystallization growth process, exhibiting significantly enhanced CO2 uptake capacity. More specifically, the abundant surface bromine (Br) vacancies in ligand-free MHP materials are demonstrated to be beneficial to photogenerated carrier separation. The electron consumption rate of LF-CPB CL for photocatalytic CO2 reduction increases 7 and 20 times over those of traditional ligand-capping CsPbBr3 nanocrystal (L-CPB NC) and bulk CsPbBr3, respectively. Moreover, the absence of ligand hindrance can facilitate the interfacial electronic coupling between LF-CPB CL and tetra(4-carboxyphenyl)porphyrin iron(III) chloride (Fe-TCPP) cocatalyst, bringing forth significantly accelerated interfacial charge separation. The LF-CPB CL/Fe-TCPP exhibits a total electron consumption rate of 145.6 μmol g−1 h−1 for CO2 photoreduction coupled with water oxidation, which is over 14 times higher than that of L-CPB NC/Fe-TCPP.