<title>Recent development of highly efficient chromophores and polymers for electro-optic device applications</title>

Abstract

A new series of highly efficient, chemically and thermally stable (Td as high as 360 °C) nonlinear optical (NLO) chromophores have been developed by using a 2-phenyl-tetracyanovinylbutadienyl group as the electron acceptor for a series of dialkyl-or diphenyl-amino substituted thiophene stilbenes. Excellent tradeoffs among absorption, molecular nonlinearity and thermal stability were achieved. Electro-optic polymers based on the guest/host systems and covalent attachment of chromophores onto high temperature polyquinoline backbones demonstrate high E-O activities ( r33 as high as 36 pm/V at 1.3 pm) and good optical, electrical and mechanical properties.

Twisted π-Electron System Electrooptic Chromophores. Structural and Electronic Consequences of Relaxing Twist-Inducing Nonbonded Repulsions

“…The semilogarithmic plots of ln( I / I 0 ) vs G 2 were fitted using the standard linear regression algorithm implemented in the Origin 7 software package; the R factor was always greater than 0.99. For pure solvents, the diffusion coefficient D t , which is directly proportional to the slope of the regression line obtained by plotting log( I / I 0 ) vs G , was estimated by measuring the proportionality constant using an HDO sample (0.04%) in D 2 O (known diffusion coefficient in the range of 274–318 K) under the exact same conditions as the sample of interest [ D t (CD 2 Cl 2 ) = 33.2 × 10 − 10 m 2 s −1 , D t (DMSO- d 6 ) = 6.5 × 10 − 10 m 2 s −1 ]. Solvents were used as internal standards to account for possible changes in solution viscosity, temperature, and gradient strength .…”

“…When designing chromophores with the aforementioned properties, the conventional approach has been to utilize strong terminal electron donor and acceptor substituents, and a planar intervening conjugated π-network . To date, theoretical calculations based on the standard “two-level model” have proven qualitatively successful in predicting β as a function of chromophore geometry and substitution .…”

Ultra-High-Response, Multiply Twisted Electro-optic Chromophores: Influence of π-System Elongation and Interplanar Torsion on Hyperpolarizability

“…The majority of known EO chromo­phores with the aforementioned properties have traditionally been designed using similar approaches: planar conjugated π-electron systems end-capped with electron donor (D) and acceptor (A) moieties . This design strategy invariably creates a strong intramolecular optical charge-transfer (ICT) transition from the ground state to the first excited state, while producing strong polarization along the π-conjugation axis.…”

An EFISH, Theoretical, and PGSE NMR Investigation on the Relevant Role of Aggregation on the Second Order Response in CHCl3 of the Push−Pull Chromophores [5-[[4′-(Dimethylamino)phenyl]ethynyl]-15-[(4′′-nitrophenyl)ethynyl]-10,20-diphenylporphyrinate] M(II) (M = Zn, Ni)

“…In the last two decades a large series of investigations has been devoted to the search for organic molecules characterized by a significant second order nonlinear optical (NLO) response as building blocks for nanostructured materials with electrooptical properties . The structural features necessary to produce a significant second order NLO response at the molecular level are now quite well-known; many organic and more recently organometallic push−pull NLO chromophores have been synthesized and investigated …”