Bandgap engineering of polymer electrolytes: A simulation based study

The aim is to study how the bandgap can be varied with different functional groups added to the polymer. The calculations are initially compared with the corresponding experimental values for various sulfone compounds. The method is further extended to PEO functionalized with groups like OH, COOH, NH2, NP and(CH3)3 Si to study how the bandgap can be engineered by varying the chemistry of the material.

METHODOLOGY

 The initial structural optimization was performed using Hartree-Fock method (using cc-pVDZ basis set). Further calculations using MP2 with the same basis set yielded results with deviation more than one volt.
 The HOMO-LUMO gap calculated (from the density of states) using DFT with Projected-augmented-wave (PAW) method and GGA functional showed close match with experimental values (read below)
 To benchmark the calculations, the HOMO-LUMO gap of sulfone based organic electrolytes were calculated and compared with the corresponding experimental values.
 These values matched closely with the experimental values of sulfone-based electrolytes as well as polyethylene oxide (PEO)
 Hence this methodology was extended to study the effect of different important functional groups on PEO.