Chirality-Controlled Spin Polarization in Perovskite Nanocrystals for Enhanced Photocatalytic CO₂ Reduction Reaction

Shao-Ku Huang^1*, Cheng-Chieh Lin², Wei-Ni Tseng³, Di-Yan Wang³, Chia-Chun Chen³, Chun-Wei Chen^1,4

¹Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan
²International Graduate Program of Molecular Science and Technology (NTU-MST), National Taiwan University, Taipei, Taiwan
³Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan
⁴Center of Atomic Initiative for New Materials (AI‐MAT), National Taiwan University, Taipei, Taiwan

* Presenter:Shao-Ku Huang, email:james80727@gmail.com

To achieve highly efficient photocatalytic performance, it is crucial to synthesize perovskite nanocrystals with excellent optical properties and effective carrier transport. Recently, chiral ligands attached to the surface of halide perovskites led to the observation of intriguing chiral photonics, such as circular dichroism (CD) and circularly or polarized luminescence (CPL). In this work, we demonstrate that photocatalytic CO₂ reduction conversion efficiencies can be significantly enhanced by chirality-regulated spin-polarization of perovskite nanocrystals. We successfully engineered and demonstrated spin-polarized 2D/3D halide perovskite nanoplates (NPLs) by incorporating chiral (MBA: Br) molecules into all-inorganic CsPbBr₃ perovskite NPLs by self-organization method, targeting their application in photocatalytic CO₂ reduction reactions. The interplay between structure, chirality, spin-polarization, and the photocatalytic activity of perovskite nanocrystals was systematically analyzed by 2D-GIWAXS, MCD, and time-resolved PL techniques. Leveraging the combined effects of induced chirality and the application of an external magnetic field, the photocatalytic CO₂ reduction efficiencies of the chiral perovskite NPLs were significantly enhanced compared to pristine CsPbBr₃ perovskite NPL counterparts. The key factor driving this enhancement is the substantial reduction in charge carrier recombination rates, resulting from the amplified spin polarization in the chiral perovskite NPLs. This property is particularly noteworthy for potential applications in spintronics, where the manipulation of spin-polarized charge carriers is critically important. Importantly, these enhanced photocatalytic CO₂ reduction efficiencies can be realized through a permanent magnet, eliminating the need for additional energy input. This strategy demonstrates significant potential and viability for future solar-to-fuel conversion applications.

Keywords: Chirality, Spin polarization, Self-recrystallization, Perovskite nanocrystal, CO₂ reduction reaction