Quantum Chemical Analysis of Electron-Donating Properties of the Active Layer of a Solar Cell Based on the Electrically Conductive Polymer PSBTBT

Abstract

The equilibrium geometry and electronic structure of oligomers modeling the polymer poly[2,6-(4,4′-bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)-alt-4,7-(2,1,3-benzothiadiazole)] (PSBTBT) with several monomeric units ranging from 1 to 10 have been calculated using density functional theory (B3LYP/6-31G**). The computational results indicate that, for the investigation of materials used in organic solar cells (including determination of frontier molecular orbital energies, exciton dissociation energies, etc.), large polymer systems can be substituted by studying their lower oligomer analogues.