Polypyrrole and polypyrrole-tetracyanoquinodinodimethane (TCNQ) have been prepared to see the energy band structure modification and associated change in the electrical and optoelectrical properties. The temperature-dependent electrical conductivity of the samples show interesting behavior, namely, higher roomtemperature conductivity of polypyrrole-TCNQ and a crossover phenomenon which may be considered as a competition between two opposing factors, charge-transfer interaction and disorderness. CHN microanalysis, UV-vis absorption spectroscopy, and positron annihilation lifetime spectroscopy corroborate the findings.

S CHAKRABARTI

D BANERJEE

R BHATTACHARYYA

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Journal of Physical Chemistry B

Since its discovery in 1977, a number of quantum chemical calculations have been attempted to simulate the metallic state of highly doped trans-polyacetylene. These simulations have focused on the possible closure of the band gap at high doping level due to a charge-induced elimination of Peierls distortion; however, conclusive demonstration of a metallic state has not been achieved. The present study presents density functional theory calculations of the band structure of highly doped trans-polyacetylene with explicit inclusion of the metal atoms in a one-dimensional periodic structure. The results indicate (i) small lattice dimerization, i.e., remnant of Peierls distortion exists even in the heavily doped trans-polyacetylene sample, (ii) charge induced closure of the Peierls gap is not a necessary condition to arrive at a metallic state in such systems, and (iii) electronic correlation, as described at the density functional theory level, with a charge induced small Peierls distortion is sufficient to achieve metallic state of highly doped n -type trans-polyacetylene even in one dimension. Furthermore, comparison of functionals that include differing degrees of electron correlation suggest that correlation promotes formation of the metallic state. © 2006 American Institute of Physics.

Fulltext

Journal of Chemical Physics

Correlation induced insulator to metal transition: A systematic density functional study on highly doped n -type trans-polyacetylene

Saturation of bipolaron, the species responsible for conduction in polypyrrole (PPy), has been studied using positron annihilation lifetime (PAL) spectroscopy, conductivity, and electron spin resonance (ESR) measurement. It is observed that when strong oxidizing agents are used, the defects are predominantly bipolarons as is evident from the PAL spectroscopic studies coupled with ESR measurements and its saturation occurs right at the onset of oxidation. However, in the case of a mild oxidizing agent, the dominant defects are bipolarons only at higher oxidizing strengths [>1.0(N)] and no saturation is attained even at the highest strength studied. Conductivity data corroborate the findings. © 1999 The American Physical Society.

Physical Review B - Condensed Matter and Materials Physics

Bipolaron saturation in polypyrrole

Russian Journal of Electrochemistry

Interfacial Catalysis, Volkov, A.G., Ed., New York: Marcel Dekker, 2003

Physica Scripta

On Some Properties of Heavy Flavor Baryons

physica status solidi (b)

Resistivity and Magnetoresistance Studies of Nb3Ir and V3Sb Compounds

Applied Surface Science

UPS studies of conducting polymers: dopant effect on conjugated polymer systems sensitive to conductivity

Enhancement of room temperature electrical conductivity of polypyrrole by chemical modification

Journal	Journal of Physical Chemistry B
Publisher	AMER CHEMICAL SOC
ISSN	1089-5647