Circular dichroism — II. Analytical applications

Purdie, Neil; Swallows, Kathy A.; Murphy, Laura H.; Purdie, Robin

doi:10.1016/0165-9936(90)87108-x

Cited by 20 publications

(19 citation statements)

References 15 publications

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“…Such a CD signature is known as the bisignate Cotton effect. Each bisignate signal may be related to the splitting of the energy level of inorganic part under the influence of chiral organic ligand into two new sublevels, which are preferentially excited by the opposite circular polarization. , Here, five bisignate CD signals and absorption peaks demonstrate the existence of five transition energy levels or bands, while in previously reported chiral perovskites or chiral hybrid metal halides, only one or two bisignate signals can be observed. , Furthermore, the effective refractive index n and extinction coefficient κ (Figure c and Table S4) of ( R -MBA)BiI 4 film were also measured by a spectroscopic ellipsometer. The dispersion relation of n relates to the phase mismatch on SHG and THG, as discussed later.…”

Section: Resultsmentioning

confidence: 77%

Strong Second- and Third-Harmonic Generation in 1D Chiral Hybrid Bismuth Halides

et al. 2021

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Breaking the symmetry of a crystal structure can enable even-order nonlinear activities, including second-harmonic generation (SHG). The emerging chiral hybrid organic–inorganic metal halides feature unique optical and electronic properties and flexible crystal structures, making them a class of promising nonlinear optical materials. However, their nonlinear response performances are currently inferior to traditional nonlinear crystals, because of the lack of research on resonant enhancement and third-harmonic generation (THG). Herein, we designed chiral hybrid bismuth halides with naturally nonsymmetrical structure to enable SHG. Simultaneously, these chiral compounds preserve 1D crystal structures to create strong free exciton, broad self-trapped exciton (STE), and discrete band energy levels, which facilitate the resonant enhancement of SHG and THG susceptibilities. These new chiral films showcase superior effective SHG susceptibility (χ(2) ∼ 130.5 pm V–1 at an interesting wavelength of 1550 nm), exceeding that of the reference, a commercial LiNbO3 (χ(2) ∼ 83.4 pm V–1) single-crystal film. Furthermore, their THG intensities are even higher than their SHG intensities, with effective THG susceptibility (χ(3)) being ∼9.0 × 106 pm2 V–2 at 1550 nm (37 times that of the reference monolayer WS2). Their high SHG and THG performances indicate the promising future of these 1D chiral hybrid bismuth halides toward nonlinear optical applications.

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Section: Resultsmentioning

confidence: 77%

Strong Second- and Third-Harmonic Generation in 1D Chiral Hybrid Bismuth Halides

et al. 2021

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“…The calculations were also repeated for the CD spectra, which measures the chirality of the stacking. In fact, the magnitude of between the stacked polymer chains 34,35,36 . As the distance between the stacked polymer chains cannot dramatically change, the CD intensity thus reflects the angle by which the polymer chains are rotated.…”

Section: Chiroptical Properties In Solutionmentioning

confidence: 99%

Influence of the regioregularity on the chiral supramolecular organization of poly(3-alkylsulfanylthiophene)s

et al. 2013

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The manuscript investigates the influence of the regioregularity (RR) of poly(3-alkylsulfanylthiophene)s (P3AST) on their properties. Therefore, a series of P3ASTs (P1-P5) with different RR was synthesized using a combination of a "reversed McCullough method" and the GRIM method. The degree of RR was determined by 1 H NMR spectroscopy. A detailed chiroptical study in good solvent, poor solvent and film was performed, which revealed that the tendency to form chiral supramolecular aggregates clearly depends on the RR, but that the relation is not simply continuously increasing. Instead, the strongest effects were observed in P3ASTs with high, but not 100% RR.. As a consequence,a similar behaviour can be expected for a regioregular and an irregular P3AST. This hypothesis was tested on a regioregular and an irregular P3AST that proved to have similar chiroptical properties in a previous study. Their properties in the solid state were investigated into detail using STM and AFM.

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“…[1] The measurement of CD values is nowadays a routine analytical method, [2] which can, for example, be used to determine the structure of proteins. [3] Commonly, CD spectroscopy is related to the linear absorption of molecules.…”

Section: Introductionmentioning

confidence: 99%