Topic
Bipolaron
About: Bipolaron is a research topic. Over the lifetime, 1335 publications have been published within this topic receiving 29154 citations. The topic is also known as: bipolarons.
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TL;DR: In this article, the results of experimental studies of resonant Raman scattering (RRS) spectra from Er 3+ implantation doped and partially isomerized polyacetylene are presented.
TL;DR: In this article, a thermochemical investigation of singlet dication (bipolaron) structures in a set of 3-methyl-thiophene oligo-mers (up to the length of 24mers) was carried out.
Abstract: A thermochemical investigation of singlet dication (bipolaron) structures in a set of 3-methyl-thiophene oligo- mers (up to the length of 24-mers) was carried out. Equlibrium structures and heats of formation were calculated with the semiempirical quantum chemical method RHF/PM3 for the doubly oxidized forms. All-cisoid planar structural variants of the form An1Qn2An3 were considered, where A and Q are thiophene monomer units in aromatic and quinoidal chain segments, respectively. The types of segments were determined from their bond-length pattern. At this level of theory, di- verse structures combining both types of segments were found stable. The so-called "response equation based quantitative structure-property relationship" (REQ-QSPR) method, recently pro- posed by Fishtik et al. was used to perform and interpret regression data analysis. The REQ-based approach rationalizes mathematical treatment of stoichiometric equations. It provides a simple concept for breaking down a dataset for heat of formation into linear combination of terms that are easy to interpret in the framework of chemical groups. REQ-QSPR in- cludes arbitrary structural descriptors rather than being restricted to using only the number of chemical constituents. Ap- plied to our system, it is demonstrated that modelling nonlinear effects becomes possible as well. Supra-linear dependence of the energy with respect to the bipolaron localization length is indicated by REQ-QSPR, and detailed analysis suggests specific further calculations to carry out for improving the model.
TL;DR: In this paper, a continuum version of the SSH-like model for polydiacetylene backbone electrons is studied and the spectrum and approximate continuum equations provide support for a double sine-Gordon equation for the phase of the electron condensate.
TL;DR: In this paper, the authors describe three distinct ways that these chromophores can be incorporated in polymer structures: (1) as pendant groups attached to a PMMA backbone, (2) as formal repeat units in a copolymer, and (3) perhaps the most interesting, as surface attached functionalities in dendrimer formulations.
Abstract: Bis-(dialkylamino) and bis-(diphenylamino) substituted diphenylpolyenes have recently been shown to have exceptionally large two-photon cross-sections, and have also been used in optical power limiting (OPL) applications. Another potential mechanism for OPL in these materials involves the photogeneration of highly absorbing polaronic radical-cations or bipolaronic dications which can then function as highly absorbing reverse saturable absorbers (RSAs). The synthesis of series of these unique polyenes has been carried out, as well as studies of chemically induced bipolaron formation in solution. In order to actually be used in OPL devices, it is probable that these chromophores will need to be incorporated into polymer formulations, In this paper we describe three distinct ways that these chromophores can be incorporated in polymer structures: (1) as pendant groups attached to a PMMA backbone, (2) as formal repeat units in a copolymer, and (3) perhaps the most interesting, as surface attached functionalities in dendrimer formulations. The formation of bipolaron charge species in these polymers will be addressed.
TL;DR: In the case of Ba2Sr2YCu2O8 single crystals at compositions below that for metallic conduction, the electrical resistivity decreases with increasing temperature, while the Hall coefficient is temperature independent and of positive sign as discussed by the authors.
Abstract: In Ba2Sr2YCu2O8 single crystals at compositions below that for metallic conduction, the electrical resistivity decreases with increasing temperature, while the Hall coefficient is temperature independent and of positive sign. These features are explained in terms of hopping of hole-like bipolarons in the CuO2 planes.