Perspective of Chiral Colloidal Semiconductor Nanocrystals: Opportunity and Challenge

Gao, Xiaoqing; Han, Bing; Yang, Xuekang; Tang, Zhiyong

doi:10.1021/jacs.9b05973

Cited by 139 publications

(100 citation statements)

References 87 publications

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“…3f-h), and no significant direct contribution arises from chiral organic cations to the associated band edge or excitonic transitions. The CD bands in chiral NPB can originate from the coupling of dipole transition moments in the inorganic framework and the chiral organic spacer cations (the chiral screening medium surrounding the inorganic framework), as previously observed in inorganic semiconductor nanocrystals capped with chiral surface ligands 19 . The same dipolar interactions with the chiral, organic screening medium can induce excitonic CD signals in R-and S-MBPI despite their nominally centrosymmetric inorganic layers 18,27 , thus suggesting that an induced CD does not always imply substantial chirality transfer from organic to inorganic layers.…”

Section: Resultssupporting

confidence: 59%

“…Chiral organic cations have been recently employed in 2D HOIPs, resulting in ferroelectricity 16 and chiroptical properties such as circular dichroism and circularly polarized luminescence 17,18 . Notably, the inorganic-related chiroptical activity in these already reported HOIP systems is evidently an optically induced phenomenon caused by dipolar interactions with chiral cations 19,20 , and thus, the chain of evidence for structural chirality/asymmetry transfer to the inorganic layers remains incomplete if solely based on chiroptical spectroscopies. Indeed, we find (as will be discussed later) that the introduction of a chiral organic cation in 2D HOIPs does not necessarily imply a significant degree of structural chirality within the inorganic framework.…”

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confidence: 97%

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Organic-to-inorganic structural chirality transfer in a 2D hybrid perovskite and impact on Rashba-Dresselhaus spin-orbit coupling

et al. 2020

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Translation of chirality and asymmetry across structural motifs and length scales plays a fundamental role in nature, enabling unique functionalities in contexts ranging from biological systems to synthetic materials. Here, we introduce a structural chirality transfer across the organic–inorganic interface in two-dimensional hybrid perovskites using appropriate chiral organic cations. The preferred molecular configuration of the chiral spacer cations, R-(+)- or S-(−)-1-(1-naphthyl)ethylammonium and their asymmetric hydrogen-bonding interactions with lead bromide-based layers cause symmetry-breaking helical distortions in the inorganic layers, otherwise absent when employing a racemic mixture of organic spacers. First-principles modeling predicts a substantial bulk Rashba-Dresselhaus spin-splitting in the inorganic-derived conduction band with opposite spin textures between R- and S-hybrids due to the broken inversion symmetry and strong spin-orbit coupling. The ability to break symmetry using chirality transfer from one structural unit to another provides a synthetic design paradigm for emergent properties, including Rashba-Dresselhaus spin-polarization for hybrid perovskite spintronics and related applications.

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Section: Resultssupporting

confidence: 59%

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confidence: 97%

Organic-to-inorganic structural chirality transfer in a 2D hybrid perovskite and impact on Rashba-Dresselhaus spin-orbit coupling

et al. 2020

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“…Local modification by chiral ligands has been extensively investigated in semiconductor nanocrystals. [240] Due to the strong excitonic behavior of sub-5-nm quantum dot (QD) systems, significant effects of chiral molecules on chiroptical response have been observed. Several origins have been suggested: the simplest suggested origin is the coupling between electric fields of QDs and chiral molecules present on the surface without any structural changes.…”

Section: Chiral Geometry Of Inorganic Crystalsmentioning

confidence: 99%

Chiral Surface and Geometry of Metal Nanocrystals

et al. 2019

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and their microscopic assembling and folding gradually give rise to chirality and left-right asymmetry from supramolecules to organelles, cells, and macroscopic organisms. Although the origin of homochirality is still unexplained and opens to arguments, investigating the chirality of matter and its origination is a central part of understanding asymmetric physical and chemical phenomena. The importance of chirality in chemistry lies in the asymmetric biochemical reactions with different physiological effect, which has paramount importance in biochemistry and pharmaceutical industry. [3,14,15] A mirror image of chiral objects can be determined into one of the left-handed or right-handed forms of geometry, called enantiomer or enantiomorph. Both enantiomers of a chiral object consist of identical chemical compositions but indeed are significantly different in their light-matter interaction, catalysis, and biological functions. The enantioselective signaling and enzymatic reaction are attributed to the homochirality of the living organism and its biological receptors, which are only composed of l-form amino acids and d-form sugars in nature. [7,14,15] Thalidomide is often referred to as a representative but also the most tragic example. The R-form of this drug is harmless to the body and was released as a painkiller for pregnant women, but its enantiomer causes severe malformation in the limbs of infants. [15,16] Since then, it has been a requirement for drugs to be characterized as a single enantiomer to be approved. 3D chirality is a unique characteristic of life, and the stereochemical aspect of molecular materials has come to fore of modern chemistry and biology. The optical property of chiral compounds, the so-called chiroptical effect, is highly effective for observing chirality in a nondestructive manner. [17] Chiroptical effects can be used for determination of the absolute configuration and enantiomeric excess of chiral molecules and as an optical probe for estimating the 3D structure of biomacromolecules such as proteins and DNA. [18] However, in most chiral organic molecules and biomolecules, chiroptical effects are typically very weak due to the much smaller size of molecules than the wavelength of exciting light. Integration of inorganic nanomaterials is one promising method for increasing the chiroptical signal of molecules; it focuses the light into nanoscale area to maximize the lightmatter interaction. [19-22] For example, a complex spatial profile Chirality is a basic property of nature and has great importance in photonics, biochemistry, medicine, and catalysis. This importance has led to the emergence of the chiral inorganic nanostructure field in the last two decades, providing opportunities to control the chirality of light and biochemical reactions. While the facile production of 3D nanostructures has remained a major challenge, recent advances in nanocrystal synthesis have provided a new pathway for efficient control of chirality at the nanoscale by transferring molecular chirality to the geo...

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“…The TEM images showed that QD533 was encapsulated inside the L-ZIF particles while the high-resolution TEM (HRTEM) image indicated that the original crystal structure of QD533 was preserved. These results illustrated that the detected CPL signal of chiral ZIF ⊃ QD533 resulted from the induced chirality by confined chiral environment from chiral ZIFs [58,59]. In addition, through tuning the mass ratio of five kinds of QDs loaded in chiral ZIF, chiral ZIF ⊃ QDs with white circularly polarized light emission also could be obtained in the solid state.…”

Section: Tunable Cpl From Qd-loaded Chiral Mofsmentioning

confidence: 78%

Dual-Mode Induction of Tunable Circularly Polarized Luminescence from Chiral Metal-Organic Frameworks

et al. 2020

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The general approach for fabricating solid-state materials showing circularly polarized luminescence (CPL) is still in its challenge. In this work, chiral metal-organic frameworks (MOFs) with full-color and white-color circularly polarized light emission are firstly achieved through a host-guest emitter-loading strategy. Chiral zeolitic imidazolate frameworks (ZIFs, a class of MOFs) are fabricated by a facile and simple mixed-ligand coassembly pathway. Meantime, achiral dyes, quantum dots (QDs), and upconversion nanoparticles (UCNPs) are easily loaded into the chiral ZIFs during the synthetic process. Size-matched dyes can be solely encapsulated into the chiral cages of ZIF, resulting in induced CPL and enhanced luminescence efficiency in solid-state ZIF⊃dye composites. Large-sized QDs, after embedding into the gap of the ZIF particles, also exhibited intense CPL activity. Furthermore, through modulating the blending ratio of colored dyes or QDs in chiral ZIFs, white light-emitting ZIFs with circular polarization could be constructed in a solid state. In addition, through loading rare earth element-based upconversion nanoparticles (UCNPs) into chiral ZIFs, upconverted CPL (UC-CPL) could be achieved with a high dissymmetry factor (glum). Thus, various achiral luminophores were endowed with CPL upon coupling with chiral ZIFs, which significantly deepened and enlarged the research scope of the chiroptical materials in a solid state.

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Perspective of Chiral Colloidal Semiconductor Nanocrystals: Opportunity and Challenge

Cited by 139 publications

References 87 publications

Organic-to-inorganic structural chirality transfer in a 2D hybrid perovskite and impact on Rashba-Dresselhaus spin-orbit coupling

Organic-to-inorganic structural chirality transfer in a 2D hybrid perovskite and impact on Rashba-Dresselhaus spin-orbit coupling

Chiral Surface and Geometry of Metal Nanocrystals

Dual-Mode Induction of Tunable Circularly Polarized Luminescence from Chiral Metal-Organic Frameworks

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