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The introduction of biuret hydrogen-bonding sites onto chiral binaphthalene-based chromophores was investigated as a route to sub-micron-sized, vesicle-like aggregates endowed with chiroptical properties. The synthesis was conduct...
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The introduction of biuret hydrogen-bonding sites onto chiral binaphthalene-based chromophores was investigated as a route to sub-micron-sized, vesicle-like aggregates endowed with chiroptical properties. The synthesis was conducted from the corresponding chiral 4,4′-dibromo-1,1′-bis(2-naphthol) via Suzuki–Miyaura coupling to afford luminescent chromophores whose emission spectrum could be tuned from blue to yellow-green through extension of the conjugation. For all compounds, the spontaneous formation of hollow spheres with a diameter of ca. 200–800 nm was evidenced by scanning electron microscopy, along with strong asymmetry in the circularly polarized absorption spectra. For some compounds, the emission also displayed circular polarization with values of glum = ca. 10–3 which could be increased upon aggregation.
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While halide perovskites (HPs) have achieved enormous success in the field of optoelectronic applications, much attention has been recently drawn to the unique polarization sensitivity of HPs, either intrinsic or extrinsic, which ...
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While halide perovskites (HPs) have achieved enormous success in the field of optoelectronic applications, much attention has been recently drawn to the unique polarization sensitivity of HPs, either intrinsic or extrinsic, which makes HPs a potential candidate for innovative applications in directly polarized luminescence and detection. Herein, the research status in the field of polarization-sensitive HPs, including linear polarization and circular polarization, is comprehensively summarized. To evaluate the effectiveness of HPs in generating and detecting linearly or circularly polarized light, the principles and characterization methods of polarized luminescence and detection are introduced. Sequentially, the state-of-the-art development of the strategies that induce the linear or circular polarization characteristics of HPs is systematically reviewed, based on which the application of polarization-sensitive HPs in the field of polarization luminescence and detection are summarized. Moreover, the current challenges and opportunities are discussed, and prospects of the future development in this promising field are outlined.
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Planar chiral [2.2]paracyclophanyl-based boron fluoride complexes (3a-3d) were designed and facilely synthesized. The X-ray structure study, theoretical calculations and CD spectra reveal the intense emission and planar chiral str...
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Planar chiral [2.2]paracyclophanyl-based boron fluoride complexes (3a-3d) were designed and facilely synthesized. The X-ray structure study, theoretical calculations and CD spectra reveal the intense emission and planar chiral structures of these complexes. In particular, 3a-3d show moderate quantum yields and large Stokes shifts both in solution and solid state. Furthermore, the blue-shifted mechanochromic properties of 3a and 3b were both investigated in the solid state. This work is the first study on planar chiral boron monofluoride complexes within the boron fluoride complex field.
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Dislocation-related luminescence (DRL) in n-GaN from a-screw dislocations introduced by cracking or nanoindentation is investigated using cathodoluminescence (CL) and polarization optical spectroscopy. In strain-free samples with ...
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Dislocation-related luminescence (DRL) in n-GaN from a-screw dislocations introduced by cracking or nanoindentation is investigated using cathodoluminescence (CL) and polarization optical spectroscopy. In strain-free samples with rare array of parallel dislocations, the polarization direction one of two DRL spectral components is directed parallel while for other components, it is inclined under the angle of about 40 degrees to the dislocation line that is attributed to the theoretically predicted different orientations of chemical bonds in the cores of N and Ga partials of the dissociated a-screw dislocation. DRL investigations near the indentation prick reveal the presence of two doublet broadbands polarized at 60 degrees with respect to each other that is caused by two crossing families of screw dislocations observed with CL.
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The electronic excitation spectrum of ZnS nanowires (NWs) is characterized by cathodoluminescence ( CL) excited using the tip of a scanning tunneling microscope as a highly localized and bright source of low-energy (150-350 eV) el...
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The electronic excitation spectrum of ZnS nanowires (NWs) is characterized by cathodoluminescence ( CL) excited using the tip of a scanning tunneling microscope as a highly localized and bright source of low-energy (150-350 eV) electrons with impinging power densities in the range of up to 60 kW/cm(2) or more. The CL spectra reveal significant differences when compared with the photoluminescence spectra of ZnS NWs. The differences can be associated with the properties of the surface region of the NWs, which are preferentially emphasized in the CL spectra owing to the small probing depth of low-energy electrons.
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We report the facile synthesis of TbIII and EuIII adducts able to elicit circularly polarized luminescence. Both the sensitization of the lanthanide-ion-centered luminescence (i. e. the antenna effect) and the chiral environment a...
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We report the facile synthesis of TbIII and EuIII adducts able to elicit circularly polarized luminescence. Both the sensitization of the lanthanide-ion-centered luminescence (i. e. the antenna effect) and the chiral environment around the metal ions are brought about by commercially available enantiopure 2,6-bis (oxazolinyl)pyridine ligands (PyBox). This strategy is promising for the development of a wide range of new and simple circularly polarized luminescence (CPL) active LnIII adducts, thanks to the fine tunability of the chemical structure of the PyBox ligands.
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Helically chiral N,N,O,O-boron chelated dipyrromethenes showed solution-phase circularly polarized luminescence (CPL) in the red region of the visible spectrum (lambda(em)(max) from 621 to 663 nm). The parent dipyrromethene is des...
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Helically chiral N,N,O,O-boron chelated dipyrromethenes showed solution-phase circularly polarized luminescence (CPL) in the red region of the visible spectrum (lambda(em)(max) from 621 to 663 nm). The parent dipyrromethene is desymmetrised through O chelation of boron by the 3,5-ortho-phenolic substituents, inducing a helical chirality in the fluorophore. The combination of high luminescence dissymmetry factors (vertical bar g(lum)vertical bar up to 4.7 x 10(-3)) and fluorescence quantum yields (Phi(F) up to 0.73) gave exceptionally efficient circularly polarized red emission from these simple small organic fluorophores, enabling future application in CPL-based bioimaging.
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In this work, a numerical approach to investigate the room temperature luminescence emission from core/shell nanowire is presented where GaN quantum discs (QDiscs), periodically distributed in AlxGa1-xN nanowire, is considered as ...
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In this work, a numerical approach to investigate the room temperature luminescence emission from core/shell nanowire is presented where GaN quantum discs (QDiscs), periodically distributed in AlxGa1-xN nanowire, is considered as core and AlxGa1-xN as shell. Thin disc shaped (Ring shaped) n-doped region has been placed at the GaN/AlxGa1-xN (AlxGa1-xN/air) interface in AlxGa1-xN region in axial (radial) directions. To obtain energy levels and related wavefunctions, self-consistent procedure has been employed to solve Schrodinger-Poisson equations with considering the spontaneous and piezoelectric polarization. Then luminescence spectrum is studied in details to recognize the parameters influent in luminescence. The results show that the amount of doping, size of QDiscs and theirs numbers have remarkable effects on the band to band luminescence emission. Our numerical calculations gives some insights into the luminescence emission of core/shell nanowire and exhibits a useful tool to analyze findings in experiments.
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The laws governing polarization of luminescence in the nanostructure Si/CaF{sub}2 upon polarization of the spins of the fluorine nuclei by means of optical excitation of charge carriers are considered theoretically. The possibilit...
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The laws governing polarization of luminescence in the nanostructure Si/CaF{sub}2 upon polarization of the spins of the fluorine nuclei by means of optical excitation of charge carriers are considered theoretically. The possibility of studying experimentally the properties of nuclear spins in analyzing luminescence is shown. The polarization of luminescence is most informative in the range of excitation rates of charge carriers from 3-10 to 3·10{sup}8 sec{sup}(-1) with the CaF{sub}2 layer of thickness from 0.6 to 0.8 nm and optical excitation polarization degree of 0.1.
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摘要 :
Chiral materials capable of generating circularly polarized luminescence (CPL)
have gained rapidly growing research interest by virtue of their peculiar photophysical
characteristics and far-reaching applications. Amongst variou...
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Chiral materials capable of generating circularly polarized luminescence (CPL)
have gained rapidly growing research interest by virtue of their peculiar photophysical
characteristics and far-reaching applications. Amongst various CPL
materials, polymer-based CPL materials have constituted an important class
owing to their abundant types, ease of manufacture, high thermal stability, as
well as, tunable properties. The present work reviews the latest advances in
constructing polymer-based CPL materials, which are classified based on the
interaction modes between chiral and luminescent components, that is, covalent
interaction, non-covalent interaction, as well as, without covalent and
non-covalent interactions. The newly emerging categories of polymer-based
CPL materials, that is, nonconventional fluorescence-based CPL materials, circularly
polarized room temperature phosphorescence, and polymer-based CPL
materials with thermally activated delayed fluorescence properties are also
presented. Typical applications of the polymer-based CPL emitters in organic
light-emitting diodes, information security encryption, and optical sensors are
further discussed. Additionally, the current challenges and future perspectives
in this field are summarized. This review article is expected to stimulate more
unprecedented achievements derived from polymer-based CPL materials,
thus further promoting their future practical applications.
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