Research progress in spintronics of chiral perovskite materials

In recent years, considerable progress has been made in the research of chiral perovskite materials for spintronics. Therefore, it has become essential to summarize the relevant research results in this area. This review aims to explore the latest research progress in spin mechanics and related applications of chiral perovskites. First, we provide a brief overview of the development of chiral perovskite and discuss the relationship between the structure of chiral perovskites and the type of A cation. Second, the theoretical aspects of the band structure, spin-orbit coupling, and chirality-induced spin selectivity (CISS) of chiral perovskites are discussed. Additionally, we discuss the origin of circular dichroism (CD) and circularly polarized luminescence mechanisms based on spin-splitting exciton of chiral perovskites. Third, we review the research progress in chiral perovskite spintronic relaxation processes, focusing on the utilization and application of polarization-dependent femtosecond transient absorption spectroscopy (spin charge transport, photovoltaic devices, spin light-emitting diodes, and circularly polarized light detection). Finally, the application prospects and challenges faced by chiral perovskite materials in the field of spintronics are summarized as follows: (1) Understanding the precise relationship between chirality, the CISS effect, material composition, and morphology is crucial. Developing new optical, electrical, and magnetic experiments will facilitate quantitative analysis of the CISS effect in chiral perovskite materials. For example, the establishment and development of time and spatially resolved microspectroscopic imaging can facilitate deep investigations into the nature of the CISS effect exhibited by chiral perovskite materials. Polarization-dependent femtosecond transient absorption spectroscopy can aid in understanding the spin mechanics of chiral perovskites. Additionally, developing theoretical models can help reveal the CISS effect and guide the design of chiral perovskite materials with exceptional spin properties. (2) Enhancing the asymmetric factor and fluorescence quantum yield of chiral perovskites is a prerequisite for their practical application in circularly polarized electroluminescence devices. Further research should focus on exploring the chiral mechanism of these materials, which can serve as a theoretical basis for enhancing its asymmetry factor. A comprehensive understanding of the mechanism of chiral transfer from the molecular level to the nanoscale, coupled with the interaction between different chiral systems, can help increase the asymmetric factor of chiral perovskites to a value greater than 0.01. Moreover, the asymmetric factor and fluorescence quantum yields of chiral perovskites can be manipulated through structural engineering, such as selecting the appropriate type of vinyl and Lewis group cross-binding cations and B-site metal ions and changing the dielectric constant through halogen substitution. In addition, the design of chiral perovskite heterojunctions can achieve energy transfer-induced luminescence enhancement, optimizing the performance of circularly polarized electroluminescence devices. (3) The premise of applying chiral perovskites in spintronic devices lies in their excellent chirality. Recent reports show that the all-dielectric perovskite metasurface possesses large chirality (g(CD) similar to 0.49), making them potentially valuable in the field of spintronics. Therefore, exploring the structure optimization and physical mechanism of chiral perovskite metasurface and developing its application in spin devices is a promising research direction. (4) The study of the nonlinear CD effect of chiral perovskite materials, including second harmonic generation- and twophoton absorption-CD, has considerable potential in theoretical and practical application. Understanding the nonlinear CD effect helps to expand the application range of chiral perovskite materials. Additionally, nonlinear CD microspectroscopic imaging can provide valuable insights into the chiral mechanism and CISS effect exhibited by chiral perovskite materials.