Chiral Perovskites for Next‐Generation Photonics: From Chirality Transfer to Chiroptical Activity

Abstract

with different substances; therefore, the resulting change in polarization state can reveal the chemical configuration, [6] structural conformation, [7] and optoelectronic properties of a substance. [8] This chiroptical phenomenon and interpretation of chiral characteristics constitute the basis of chiral photonics. In particular, circularly polarized photoluminescence (CPPL) (i.e., differential emission of left-handed circularly polarized (LCP) and righthanded circularly polarized (RCP) lights) is absolutely necessary for scrutinizing the ground state of materials, [9] whereas circular dichroism (CD) spectroscopy (i.e., differential absorption of LCP and RCP lights) can provide useful information regarding the structure of the excited state of materials. [7] These complementary phenomena enable the development of advanced smart photonic technologies.A material is chiral if it cannot be superimposed on its mirror image. This phenomenon is commonly observed in natural organic compounds, such as small amino acids, saccharide, starch, and DNA. Owing to their noncentrosymmetric structure (e.g., no inversion symmetry, mirror plane, and glide plane), chiral materials exhibit nonlinear optical responses to CPL in CD and CPPL spectra. Although organic chiral materials are ubiquitous and exhibit strong chiroptical activity in the near-UV region, [10] the structural softness of organic chiral molecules makes them difficult to stack, resulting in poor charge transfer capability in practical polarization-based optoelectronic devices. Additionally, in chiral photonics research, focus should be on stable and broad wavelength tunability over the visible light region to realize optoelectronic devices based on the polarization phenomenon. In this regard, OIHPs have emerged as promising candidates for nonlinear optic devices because of their facile color tunability through halide composition engineering, [11] quantum size effects, [12] small effective mass, [13] long spin lifetime exceeding 1 ns, diffusion lengths ≈85 nm, and high electron/hole mobility. [14] A recent study demonstrated that OIHPs exhibit strong spin-orbit coupling of the electronic states, [15] spin-dependent optical selection rules, and large Rashba splitting, [16] suggesting that the OIHPs might exhibit exceptional spin polarization properties. [17] Despite the exceptional spin polarization properties, OIHP materials cannot be utilized in chiral photonics owing to their centrosymmetric crystal structure. However, the flexible crystal Organic-inorganic hybrid halide perovskites (OIHPs) are commonly used as prototypical materials for various applications, including photovoltaics, photodetectors, and light-emitting devices. Since the chiroptical properties of OIHPs are deciphered in 2017, chiral OIHPs have been rediscovered as new hybrid systems comprising chiral organic molecules and achiral inorganic octahedral layers. Owing to their exceptional optoelectrical properties and structural flexibility, chiral OIHPs have received a considerable amount of attention...

Frontiers in circularly polarized luminescence: molecular design, self-assembly, nanomaterials, and applications

“…Kim et al [341] obtained chiral optically active semiconductor films by mixing non-chiral polymer poly(3-alkylthiophene) (P3CT) and a general-purpose chiral molecule 1,1′-binaphthyl-2,2′diamine (BN). In this hybrid film, chirality in small molecules extends to the non-chiral conjugated polymer, since that the intermolecular interactions between the two materials are an important chiral transfer mechanism [2]. The controllable phase separation and crystallization process of the mixture system also induces the formation of vertically separated heterojunction with top BN and bottom P3CT/BN mixture structure.…”

“…Polarization is one of the inherent and important properties of light, which is very important in display, remote sensing, target identification, information storage fields and so on [1][2][3][4]. Unlike the intensity and wavelength of light, polarization has the ability to distinguish the information of light from three dimensions [5].…”

“…Experimentally, the g abs value can be determined by Eq. ( 2): g = ellipticity 32980 × absorbance (2) abs where the "ellipticity (in mdeg)" and "absorbance" values can be directly obtained from CD spectral measurement.…”

Elucidating the origin of chiroptical activity in chiral 2D perovskites through nano-confined growth

“…Chiral photonics based on chiroptical phenomena have attracted tremendous scientific interest in a wide variety of fields, such as opto-spintronics 1 , 2 , optical information processing 3 , biological science 4 , chiral biosensing 5 , 6 , and quantum computing 7 , 8 . Chiral materials, which are commonly found in natural organic compounds, exhibit nonlinear optical responses depending on the polarization state of the circularly polarized light (CPL) owing to their inherently non-centrosymmetric nature.…”

Ultrasensitive Near‐Infrared Circularly Polarized Light Detection Using 3D Perovskite Embedded with Chiral Plasmonic Nanoparticles

“…The incident left-handed circularly polarized light (LCPL) or right-handed circularly polarized light (RCPL) can induce differentiated circulation of electronic charges (i.e., helical redistribution) in chiral materials, resulting in different degrees of light absorption. [1][2][3] Because this function reflects intrinsic opto-physical and chemical information regarding materials, [4,5] directly distinguishing between the two polarizations of CPL without subsidiary optical components (e.g., linear polarizer and quarter-wave plate) enables miniaturization of the integrated device at a low cost and has considerable potential in many applications, including quantum optics, [6] encrypted optical communication, [7] spintronics, [8] security surveillance, [9] and remote sensing. [10] In nature, stomatopod crustaceans (e.g., mantis shrimps, cuttlefish, and octopus) can discriminate the circular polarization of light; the acquired information assists with predation, navigation, and intraspecific communication within various ecosystems.…”