Elastic constants and mechanical properties of PEDOT from first principles calculations

Abstract

In this work, we report about the electronic and elastic properties of crystalline poly(3,4-ethylenedioxythiophene), known as PEDOT, in an undiluted state, studied in the framework of semilocal DFT, using the PBE and PBEsol exchange-correlation functional and PAW pseudopotentials. Contrary to previous molecular dynamics simulations, our calculations revealed that the most stable state structure of pristine PEDOT is monoclinic. We calculated the 13 independent elastic constants and the elastic compliance which enables us to establish other elastic properties of pristine PEDOT; the Pugh's ratio and the Vicker's hardness computed with PBE and PBEsol are in good agreement with each other. Finally, we compute the directional elastic modulii and found remarkable differences between different DFT functionals.

Spectroscopic Characterization of Pedot:pss Conducting Polymer by Resonance Raman and Serrs Spectroscopies

“…6 The use of polymers dispersed in low boiling point solvents allowed the application of low-cost deposition techniques, such as spin coating, to produce homogeneous thin films with high reproducibility, resulting in both the lowering of the costs of production and improvements in the power conversion efficiency. [7][8][9] Many efforts have been done to parameterize the polymeric dispersion syntheses in order to find the most suitable applications. Due to the electronic structures of conducting polymers, the use of resonance Raman (RR) [10][11][12] and surface-enhanced resonance Raman scattering (SERRS) 13,14 spectroscopies can provide valuable information for the characterization of their dispersions and films.…”

Comparison of dispersion-corrected exchange-correlation functionals using atomic orbitals

“…Semilocal XC functionals, which are all characterized by a localized XC hole density [5,6], can recognize various types of interactions and density regimes, such as covalent, metallic, and some short-ranged weak bonds [4,[7][8][9], can be utilized for an accurate description of surface asymptotics [10], and can describe the dimensional crossover of the XC energy [11][12][13] for various confinements [14]; but they cannot possibly describe correctly van der Waals (vdW) interactions even at short range [15]. Whenever vdW interactions play a role, one can use the so-called DFT-D semiempirical approach [16][17][18][19][20][21][22][23][24][25][26][27][28][29], which is based on the cancellation of various errors especially at a short range [15]. We recall that DFT-D introduces a force-field correction to the semilocal result, of the form…”

Dispersion-corrected PBEsol exchange-correlation functional

“…The densitydependent model of Johnson and Becke [47] incorporates C 8 and C 10 as well. The PBEsol-D2 functional has been used in various applications [48][49][50][51][52] but not as often as the PBE-D2 functional.…”