Dynamical and turbo TDDFT study of polyaniline emeraldine for CO, NH 3 , CO 2 gas sensing
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Dynamical and turbo TDDFT study of polyaniline emeraldine for CO, NH3, CO2 gas sensing Nasim Hadian‑Jazi1,2 · Nasser Zare‑Dehnavi1,2 · Ismaeil Abdolhosseini‑Sarsari1,2 Received: 17 January 2020 / Accepted: 26 March 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The adsorption of gas molecules CO, NH3 , CO2 on polyaniline emeraldine salt affects its electronic states and IR active vibrational modes. Hartree–Fock/DFT hybrid functionals (HSE06) and Liouville–Lanczos approach, which implemented to solve time-dependent density-functional perturbation problem, have been carried out to compute the response mechanism (absorption spectra) of polyaniline emeraldine salt (PANI ES) oligoanalines (with two to six rings) to gas molecules after structure optimization. The optical absorption spectrum analysis of the all (nPANI ES-X) and isolated nPANI ES indicates that the 𝜆max is shifted red or blue based on adsorbed gas type. We found it out that the electronic and optical features corresponding to complexes are more sensitive to the NH3 adsorption. The vibrational modes and IR intensities were determined by Hessian matrix diagonalization and derivation of the dipole moments, respectively. The values of IR intensity and vibrational frequencies are changed by the number of PANI ES rings and also when gas molecules get absorbed on it. Keywords IR spectrum · Absorption optical spectrum · TDDFT · Polyaniline emeraldine · Gas sensors
1 Introduction Some gas molecules such as CO, NH3 , CO2 can make serious problems, and therefore their detection at ppm and/ or ppb concentration is so important for the human safety and health [1–6]. Many articles recently gave emphasis to property of gas sensors with high sensitivity, high selectivity, high stability, short response, recovery and small power waste [7–11]. In the last few years, a new generation of gas sensors has been prepared, using conductive polymers (CPs) [12–16]. It is found that the conductive polymers could be utilized for detecting small concentration of CO, NH3 , CO2 with high sensitivity at ambient temperature [17]. Conductive polymers as polyaniline (PANI), poly (o-phenylenediamine) (POPD), polypyrrole (PPY), and poly (3,4-ethylenedioxythiophene) (PEDOT) have received a lot * Nasser Zare‑Dehnavi [email protected] 1
Department of Physics, Central Tehran Branch, Islamic Azad University, Tehran, Iran
Computational Physical Sciences Research Laboratory, School of Nano‑Science, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395‑5531, Tehran, Iran
2
of attention specially in field of sensors, since the first discovery of polyacetylene (CH)x in 1977 [18, 19] by reason of their high sensitivities, quick response time, good mechanical features, and room temperature action [3, 20, 21]. Many single-subject studies demonstrate their biosensing and gas sensing capabilities [14, 22]. Among CPs, PANI was studied as gas sensors, experimentally and theoretically. People hope they will profit greatly from its low cost, high
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