Chirality-Regulated Spin-Polarization of Perovskite Nanoplates for Photocatalytic CO Reduction Reaction.

Manipulating spin polarizations of photoexcited electrons has been found to play a vital role in enhancing photocatalytic CO conversion by suppressing carrier recombination. In this work, photocatalytic CO reduction conversion efficiencies are significantly enhanced by chirality-regulated spin-polarization of CsPbBr perovskite nanocrystals. We propose the chirality-regulated perovskite thin films by incorporating chiral molecules (MBA:Br) into all-inorganic CsPbBr perovskite nanoplates (NPLs), resulting in (R)- and (S)-2D Ruddlesden-Popper perovskite (RPP)/NPL hybrids. In this configuration, the chiral 2D RPP perovskites offer a significant chiroptical response that promotes the generation of spin-polarized electrons. The chirality-regulated spin-polarization of 2D RPP/NPLs hybrid perovskite thin films has significantly suppressed charge carrier recombination rates, thereby enhancing the efficiency of photocatalytic CO reduction. By harnessing the synergistic effects of induced chirality and the application of an external magnetic field of 0.3 T, the photocatalytic CO reduction efficiencies of the chiral perovskites can be enhanced to be five times that of the pristine CsPbBr perovskite NPLs. The interplay between structure, chirality, spin polarization, and carrier dynamics associated with the enhanced photocatalytic activity of perovskite nanocrystals was systematically analyzed using grazing-incidence wide-angle X-ray scattering (GIWAXS) spectroscopy, magnetic circular dichroism (MCD) spectroscopy, and time-resolved photoluminescence (PL) techniques. Our results pave the way for the manipulation of spin-polarized electrons through chirality-regulated perovskite nanocrystals, significantly enhancing photocatalytic CO reduction efficiencies and highlighting their strong potential for future solar-to-fuel conversion applications.