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 paper, the growth, electrochemical cycling and overoxidation of polypyrrole in 1M NaClO4 were investigated using in situ ellipsometry and Fourier Transform Infra Red spectroscopy.
227 citations
TL;DR: In this article, the authors investigated the redox states of long oligothiophenes and showed that two isolated radical cations (polarons) exist simultaneously on a π-conjugated chain or do they coalesce into a single, doubly charged spinless (bipolaron) deformation.
Abstract: Can two isolated radical cations (polarons) exist simultaneously on a π-conjugated chain or do they coalesce into a single, doubly charged spinless (bipolaron) deformation? This long-standing question, fundamental to charge transport in conducting polymers, is now resolved by an investigation of the redox states of long oligothiophenes (below) in solution. In contrast to short oligothiophenes, for long oligothiophene dications two individual polarons prevail because of the decrease in Coulomb repulsion energy obtained by moving the two charges apart.
216 citations
PARC1
TL;DR: In this paper, the slow formation of hole bipolarons is proposed to explain the bias-stress effect that is observed in some polymer thin-film transistors (TFT) and the observed that holes are removed from the channel at a rate proportional to the square of their concentration.
Abstract: The slow formation of hole bipolarons is proposed to explain the bias-stress effect that is observed in some polymer thin-film transistors (TFT). The primary evidence is the observation that holes are removed from the channel at a rate proportional to the square of their concentration. As bound hole pairs form, they deplete the TFT channel of mobile holes, which reduces the TFT current and causes a threshold voltage shift. The slow rate of bipolaron formation is attributed to the mutual Coulomb repulsion of the holes. Contrasting stress effects in different polymers are related to the magnitude of the bipolaron binding energy. Present experiments cannot distinguish whether the bipolarons are intrinsic, or associated with disorder, interfaces, or impurities.
205 citations
Book•
21 Oct 2009
TL;DR: In this paper, the current status of Polarons and open problems are discussed and a discussion of the current state of polarons and bipolarons in advanced materials is presented.Continuum Polaron, Lattice Polaron and Multipolaron Problem
Abstract: Continuum Polaron.- Lattice Polaron.- Bipolaron.- Multipolaron Problem.- Polarons and Bipolarons in Advanced Materials.- Current Status of Polarons and Open Problems.
194 citations
TL;DR: Metal-insulator-semiconductor structures with poly (3-hexyl thienylene) as the active semiconductor are fabricated and the strong confinement deduced for the polaron is contrasted with the weak confinement observed for bipolarons.
Abstract: We have fabricated metal-insulator-semiconductor structures with poly(3-hexyl thienylene) as the active semiconductor. Optical-absorption bands due to injected carriers seen near 0.4, 1.80, and 2.16 eV are assigned to the optical transitions of the singly charged polaron, which is expected to be the thermodynamically favored excitation under these experimental conditions. Additional absorption bands at 0.5 and 1.18 eV are assigned to optical transitions of doubly charged bipolarons. We contrast the strong confinement deduced for the polaron (gap states separated by 1.80 eV) with the weak confinement observed for bipolarons (gap states separated by 0.7 eV).
190 citations