Elastic constants and mechanical properties of PEDOT from first principles calculations

In this work, we report about the electronic and elastic properties of crystalline poly(3,4-ethylenedioxythiophene), known as PEDOT, in the crystalline form, 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.