Synthesis and Characterization of Poly(3‐Hexylthiophene) for Organic Solar Cells

Abstract

Poly(3‐hexylthiophene) (P3HT) has been successfully synthesized through McCullough route. The influence of nickel catalyst content on molar mass (Mn and Mw), dispersity (Đ), regioregularity (rr), as well as optical, thermal, and morphological properties is systematically investigated. The results evidence that polymer dispersities are narrow, Mn and rr values decrease with the augmentation of catalyst content. Polymer solution in different solvents (chloroform and dichlorobenzene) show similar optical band gaps. Solid state band gap of obtained material is lower than in solution, which confirms the reorganization of polymer chains in solid state. Both polymers show good thermal stability and their morphologies are tightly influenced by the monomer/catalyst ratio in the synthesis. Two main morphologies are obtained, for the higher molar mass P3HT it is nodule‐like, while the lower Mn presented rod form. The fore polymer combined with PCMB results in lower root mean square (RMS) indicating smoother morphology, which is more appropriate for solar cells application.