Second-order nonlinearity in poled-polymer systems

Burland, D. M.; Miller, Robert D.; Walsh, Cecilia A.

doi:10.1021/cr00025a002

Cited by 1,427 publications

(833 citation statements)

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“…Cooling the polymer in the presence of the field traps the chromophores so that the polymer retains its nonlinear optical character. It is thought that polymers treated in this way could serve as useful materials for construction of electrooptic devices; the large hyperpolarisabilities of well chosen organic molecules and formation of components of complex shape being just some likely advantages [11]. However, the stability of a poled polymer is a major concem, the "freezing in" technique suffering from random diffusional processes which degrade the SHG efficiency over a period of time.…”

Section: Relaxation After Alignment In An Electrostatic Fieldmentioning

confidence: 99%

Second harmonic generation in partially ordered media and at interfaces: analysis of dynamical and orientational factors

Andrews¹,

Hands²

1996

Chemical Physics

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A new method of modelling molecular orientational dynamics is presented and illustrated by application to optical second harmonic generation (SHG). The method highlights the intricate dependence of the harmonic signal on the form and evolution of the molecular orientational distribution, and reference is made to some examples taken from the recent literature. Specifically, the cases considered relate to SHG in (a) poled polymers, (b) molecules oriented within molecular sieves and (c) molecules in films or adsorbed on surfaces. The technique invokes rotational averages weighted by static or time-dependent distribution functions expressed in terms of Legendre polynomials. Rotational diffusion is used to model the decay of second harmonic intensity associated with a growth or recovery of bulk isotropy, the results allowing several discrete contributions associated with different time constants to be characterised. For polarisation studies using surfaces and films, it is shown that caution is required in how the results are interpreted to reflect molecular orientation, approximations in commonly employed theory readily producing spurious results.

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Section: Relaxation After Alignment In An Electrostatic Fieldmentioning

confidence: 99%

Second harmonic generation in partially ordered media and at interfaces: analysis of dynamical and orientational factors

Andrews¹,

Hands²

1996

Chemical Physics

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“…The DFT approach allows the definition of molecular NLO properties as an inexpensive way to design molecules by analyzing their potential and determine the hyperpolarizability tensors of molecules before synthesis of the molecules [28,29]. The significance of the polarizability and the first hyperpolarizability of a molecular system depends on the efficient electronic communication between donating and withdrawing groups, due to the fact that it is the basis to intramolecular charge transfer [30].…”

Section: Nonlinear Optical Studiesmentioning

confidence: 99%

Optimized geometry, vibration (IR and Raman) spectra and nonlinear optical activity of p-nitroanilinium perchlorate molecule: A theoretical study

Tamer

Atalay

Avcı

et al. 2016

Materials Science-Poland

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The molecular modeling of p-nitroanilinium perchlorate molecule was carried out by using B3LYP and HSEH1PBE levels of density functional theory (DFT). The IR and Raman spectra were simulated and the assignments of vibrational modes were performed on the basis of relative contribution of various internal co-ordinates. NBO analysis was performed to demonstrate charge transfer, conjugative interactions and the formation of intramolecular hydrogen bonding interactions within PNAPC. Obtained large dipole moment values showed that PNAPC is a highly polarizable complex, and the charge transfer occurs within PNAPC. Hydrogen bonding and charge transfer interactions were also displayed by small HOMO-LUMO gap and molecular electrostatic potential (MEP) surface. The strong evidences that the material can be used as an efficient nonlinear optical (NLO) material of PNAPC were demonstrated by considerable polarizability and hyperpolarizability values obtained at DFT levels.

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“…Azo polymers have been shown to be excellent NLO materials (Yesodha et al, 2004;Delaire and Nakatani, 2000;Dalton et al, 1995;Burland et al, 1994). In azo systems, one has the additional advantage of using light to affect the chromophores.…”

Section: Photoinduced Motions and Modulationsmentioning

confidence: 99%