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, a nonadiabatic dynamic method was used to investigate the charge injection process from metal electrode to a nontegenerate polymer in a metal/polymer/ metal structure.
Abstract: Charge injection process from metal electrode to a
nondegenerate polymer in a metal/ polymer/ metal structure has been
investigated by using a nonadiabatic dynamic method. We
demonstrate that the dynamical formation of a bipolaron
sensitively depends on the strength of applied electric field, the
work function of metal electrode, and the contact between the
polymer and the electrode. For a given bias applied to one of the
electrode (V0) and coupling between the electrode and the
polymer (t′), such as V0=0.79 eV and t′=1 eV,
the charge injection process depending on the electric field can
be divided into the following three cases: (1) in the absence of
the electric field, only one electron tunnels into the polymer to
form a polaron near the middle of the polymer chain; (2) at low
electric fields, two electrons transfer into the polymer chain to
form a bipolaron; (3) at higher electric fields, bipolaron can not
be formed in the polymer chain, electrons are transferred from the
left electrode to right electrode through the polymer one by one
accompanying with small irregular lattice deformations.
11 citations
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TL;DR: In this paper, a combined investigation of the Raman cross-section for a benzene ring vibrational mode at 1630 cm−1 and of the spin concentration as a function of the e.c. potential in polyaniline identified the polaron state as the initially generated doping-induced species.
Abstract: A combined investigation of the Raman cross-section for a benzene ring vibrational mode at 1630 cm−1 and of the spin concentration as a function of the e.c. potential in polyaniline identified the polaron state as the initially generated doping-induced species. The polaron transition energy is determined as 2.75 eV. Increasing oxidation quenches the Raman signal and decreases the spin concentration until, for oxidation potentials higher than 700 mV vs. SCE, both signals reappear indicating a reduction of the polaron lattice or of bipolaron states to individual polarons.
11 citations
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TL;DR: In this paper, the a.c. conductivity of a glassy selenium-tellurium system (Se100- petertodd xTex) was investigated using correlated barrier hopping (CBH) model.
Abstract: Temperature and frequency dependence of a.c. conductivity have been studied in glassy Se100-
x
Te
x(x = 10, 20 and 30) over different range of temperatures and frequencies. An agreement between experimental and theoretical results suggests that the a.c. conductivity behaviour of selenium-tellurium system (Se100-
xTex)can be successfully explained by correlated barrier hopping (CBH) model. The density of defect states has been determined using this model for all the glassy alloys. The results show that bipolaron hopping dominates over single-polaron hopping in this glassy system. This is explained in terms of lower values of the maximum barrier height for single-polaron hopping. The values of density of charged defect states increase with increase in Te concentration. This is in agreement with our previous results obtained from SCLC measurements.
11 citations
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TL;DR: In this article, two electropolymerizable monomers were synthesized, namely dithieno[3,2-b:2′,3′-d]pyrrole N-functionalized with 4-(2-heptylthiazol-4-yl)phenyl (DTP1) and 4-(5-octylthiophen-2-yl)-phenyl(DTP2) groups.
11 citations
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TL;DR: In this paper, the ac conduction mechanism in copper oxide nanoparticles with 8 nm size, synthesized by a precipitation method, was studied by analyzing ac conductivity in the frequency range of 50 Hz-1 MHz and in the temperature range of 373-573 K. X-ray diffraction and transmission electron microscopy were employed for the structural and morphological characterization of CuO nanoparticles.
Abstract: The ac conduction mechanism in copper oxide nanoparticles with 8 nm size, synthesized by a precipitation method was studied by analyzing ac conductivity in the frequency range of 50 Hz–1 MHz and in the temperature range of 373–573 K. X-ray diffraction and transmission electron microscopy (TEM) were employed for the structural and morphological characterization of CuO nanoparticles. The experimental and theoretical investigations suggested that the ac conduction mechanism in CuO nanoparticles can be successfully explained by a correlated barrier hopping model, which provided reasonable values for the maximum barrier height and characteristic relaxation time. It was also found that bipolaron hopping become prominent up to a particular temperature and beyond that single polaron hopping predominates. Physical parameters such as hopping distance and density of defect states were also calculated. Photoluminescence studies confirm the presence of a surface defect in CuO nanoparticles.
11 citations