手性钙钛矿材料的自旋电子学研究进展

Research progress in spintronics of chiral perovskite materials

研究电子的自旋性质对自旋电子器件的发展非常重要.虽然各类铁磁金属以及合金半导体材料的自旋电子学研究取得了重大进展,但是这些材料在合成时需要高温处理,应用时则需要满足晶格匹配条件并施加磁场或者极端温度.手性钙钛矿材料的特殊结构赋予了其新的自旋电子性质,且相关应用可以在室温下实现,这将其与传统的自旋电子材料区分开来.近年来,手性钙钛矿材料的自旋电子学研究取得了重要进展,非常有必要对相关研究结果进行总结.基于此,本文评述了手性钙钛矿的自旋动力学以及相关应用的最新研究进展.首先,本文简单介绍了手性钙钛矿的发展.其次,从理论上阐述了手性钙钛矿的能带结构、自旋轨道耦合及手性诱导自旋选择性效应.再次,回顾了手性钙钛矿自旋电子弛豫过程及其应用(自旋电荷输运、光伏器件、自旋发光二极管及圆偏光探测等)的研究进展.最后,对手性钙钛矿材料在自旋电子学领域的应用前景以及面临的挑战进行了总结和展望.

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 polarizationdependent 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(gCD~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.