Analysis of temperature-dependent conductivity of nanotubular polyaniline on the basis of phonon-assisted tunneling theory

Positive temperature coefficient of resistivity of polyaniline films in the framework of phonon-assisted tunnelling model

“…Very recently we have shown that temperaturedependent conductivity of nanotubular PANI can be explained by the model based on a phononassisted tunnelling (PhAT), as a mechanism of free charge carrier's generation process [13]. The PhAT theory predicts an absorption/emission of phonons in the process of charge carrier tunnelling.…”

Electronic transport mechanism in polydiacetylene crystals — variable range hopping or phonon-assisted tunnelling

“…, wherehω is the phonon energy, ε T is the energy depth of the center, e is the electron charge, and a is the electron-phonon interaction constant (a = Γ 2 0 /8(hω) 2 ).This relatively simple expression was proved to be valid to describe not only the temperature-dependent current-voltage data in inorganic materials [10], but also in the case of π-conjugated organic conducting polymers [6][7][8]. Consequently, we will use this equation to explain the peculiarities of temperature-dependent current in polydiacetylene single crystals.…”

“…We argue that the temperature dependence of the conductivity in PDA crystals [3] as well as in DCH-PDA crystals measured by Elman et al [5] can be well described in terms of phononassisted tunnelling, as the charge carriers delocalization process. The temperatureBrought to you by | MIT Libraries Authenticated Download Date | 5/11/18 3:39 AM dependent tunnelling process has been also used for explanation of the temperaturedependent of I − V characteristics in some polymers [6][7][8].…”

A role of phonon-assisted tunnelling in electrical conductivity of carbon nanotube networks

“…A plenty of mechanisms used for explanation of the temperature dependence of current peculiarities in SWCNT networks implies that the conduction mechanism in these materials is not fully understood. Recently we have shown that the temperature-dependent conductivity of nanotubular polyaniline [18] and other polymers [19,20] can be explained by a model based on a phonon-assisted tunnelling (PhAT), as a mechanism of free charge carriers generation. Since the PhAT theory predicts an absorption / emission of phonons in the process of carrier tunnelling, the variation of current / conductivity with temperature will be determined by the competition of the absorption and emission of phonons.…”

“…In this paper, we focus on the data of the crossover from a non-metallic to metallic sign of conductivity at temperatures between 4 K and 200 K and show that the trend of conductivity with temperature is well accounted for by the PhAT model similar to that used for polymers [18][19][20].…”