Synthesis of sulfone-substituted thiophene chromophores for second-order nonlinear optics (original) (raw)
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Synthesis and characterization of thiazole-containing chromophores for second-order nonlinear optics
Journal of Materials Chemistry, 1999
Push-pull thiazole-containing nonlinear optical chromophores with dicyanovinyl and tricyanovinyl acceptors, along with their thiophene analogs, have been synthesized and characterized. The onset temperatures of thermal decomposition of these chromophores determined by DSC are above 240°C. The redox properties of the chromophores were studied by cyclic voltammetry and the results reveal the electron-deficient (thiazole) and electron-excessive (thiophene) nature of the heterocycles. Experimental measurements of second-order nonlinear optical response ( m·b) indicate that the combination of either a thiazole or thiophene conjugating unit and a tricyanovinyl acceptor results in a nonlinear optical chromophore exhibiting substantial molecular hyperpolarizability (m·b ca. 7000×10−48 cm6 at 1907 nm).
Chemical Physics Letters, 2001
A series of thiophenic monomers functionalized with dierent chromophoric groups have been optically characterized in view of preparation of polymeric ®lms for second-order nonlinear optics and electrooptics. In order to investigate the optical behaviour inside a solid host matrix, the molecules have been physically dispersed in poly(methylmethacrylate) (PMMA) ®lms and poled through high-temperature corona-poling for characterization through in situ second harmonic generation and ex situ angle-resolved spectroscopy. The values of dipole moment l and optical hyperpolarizability b have been estimated inside the host matrix and related to the molecular structure. For one of the chromophores the long-term reorientation dynamics has been monitored in order to investigate the stability and the interaction with the polymeric environment.
Organic Electronics, 2009
Two new trifunctional thiophene based dyes suited for crosslinking were synthesised from the same structural core, i.e. 4-[[5-[(4-nitrophenyl)azo]-2-thienyl]azo]benzenamine. Crystal structure and second order nonlinear optical properties were determined on a related difunctional dye that can be considered as a representative and simplified model of the trifunctional compounds, determining on it the lb value of 4950 Â 10 À48 esu (6111 Â 10 À80 C 2 m 4 V À2). The presence of three acrylic or hydroxyl functional groups in the dyes allowed to incorporate the chromophoric fragment into two different kinds of crosslinked materials possessing ''frozen" long-lasting dipole order. The traditional guest-host approach used for one of them was exceeded by covalently anchoring the chromophore to a functionalised polymer in a three-dimensional unique network. In this way a promising NLO active material was obtained. The value of the d 33 coefficient (determined by SHG measurement using the Maker fringe technique) was 11 pm/V for the poled/crosslinked film. Very good thermal and temporal stability of the chromophore poling-induced dipole alignment was attained.
Journal of Organic Chemistry, 2002
Two series of push-pull chromophores built around thiophene-based π-conjugating spacers rigidified either by covalent bonds or by noncovalent intramolecular interactions have been synthesized and characterized by UV-vis spectroscopy, electric field induced second harmonic generation (EFISH) and differential scanning calorimetry. Comparison of the linear and second-order nonlinear optical properties of chromophores based on a covalently bridged dithienylethylene (DTE) spacer with those of their analogues based on open chain DTE shows that the rigidification of the spacer produces a considerable bathochromic shift of the absorption maximum together with a dramatic enhancement of the molecular quadratic hyperpolarizability (µ ) which reaches values among the highest reported so far. A second series of NLO-phores has been derived from a 2,2′-bi(3,4-ethylenedioxythiophene) (BEDOT) π-conjugating spacer. As indicated by X-ray and UV-vis data, rigidification of the spacer originates in that case, from noncovalent intramolecular interactions between sulfur and oxygen atoms. Again, comparison with the parent compounds based on an unsubstituted bithiophene spacer reveals a marked red shift of the absorption maximum and a large enhancement of µ . In an attempt to distinguish the contribution of the electronic and geometrical effects of the ethylenedioxy group, a third series of NLO-phores based on 3,4-ethylenedioxythiophene (EDOT) and 3,4-dihexyloxythiophene spacers has been synthesized. Comparison with compounds based on unsubstituted thiophene shows that, despite a red shift of λ max , introduction of alkoxy groups leads to a decrease of µ . Theoretical calculations indicate that this effect results from a decrease of the dipole moment (µ) caused by the auxiliary electron-donor alkoxy groups on the thiophene ring. In contrast, replacement of BT by BEDOT produces an increase of µ, which associated with the noncovalent rigidification of the BT system accounts for the observed enhancement of µ . * Corresponding author. Fax 33(0)2 41 73 54 05. (2) (a) Verbiest, T.; Houbrechts, S.; Kauranen, M.; Clays, K.; Persoons, A. Blanchard-Desce, M.; Alain, V.; Bedworth, P. V.; Marder, S. R.; Fort, A.; Runser, C.; Barzoukas, M.; Lebus, M. S.; Wortmann, R. Chem.
Tetrahedron, 2002
Novel p-extended tetrathiafulvalene (exTTF) derivatives connected to a p-nitrophenyl electron-accepting unit through a p-conjugated oligoenic spacer (14a-c -16a-c) show good second-order optical nonlinearities. The effect of the conjugation length of the oligoenic spacer and the presence of a thiophene ring in the p-conjugated bridge (20a-c) have been theoretically (PM3) and/or experimentally (EFISH technique) studied. The redox properties of the novel compounds have been investigated by cyclic voltammetry (CV) and the CV data reveal the good donor ability of the exTTF unit. Although the energy of the intramolecular charge-transfer (ICT) band displayed by these compounds and their redox potentials are fairly insensitive to the nature of the conjugated spacer linking the donor and the acceptor moieties, an increase in their second order nonlinear optical responses is observed on increasing the conjugation lengths. Compounds 20a-c bearing a thiophene ring show a remarkable thermal stability with decomposition temperatures over 4008C. A new series of D-p-A compounds (23a-c) bearing a 1,3-dithiol-2-ylidene donor unit has also been synthesized and studied. q
International Journal of Polymer Science, 2015
Two copolymers of 3-alkylthiophene (alkyl = hexyl, octyl) and a thiophene functionalized with disperse red 19 (TDR19) as chromophore side chain were synthesized by oxidative polymerization. The synthetic procedure was easy to perform, cost-effective, and highly versatile. The molecular structure, molecular weight distribution, film morphology, and optical and thermal properties of these polythiophene derivatives were determined by NMR, FT-IR, UV-Vis GPC, DSC-TGA, and AFM. The third-order nonlinear optical response of these materials was performed with nanosecond and femtosecond laser pulses by using the third-harmonic generation (THG) andZ-scan techniques at infrared wavelengths of 1300 and 800 nm, respectively. From these experiments it was observed that although the TRD19 incorporation into the side chain of the copolymers was lower than 5%, it was sufficient to increase their nonlinear response in solid state. For instance, the third-order nonlinear electric susceptibility (χ3) o...