Synthesis and characterization of low bandgap poly(dithienosilole vinylene) derivatives

Abstract: Two low bandgap conjugated polymers containing vinylene unit on their main chains, poly(dithienosilole vinylene) derivatives P1 and P2, were synthesized by Pd-catalyzed Stille-coupling method. The two polymers show good solubility in common organic solvents, broad absorption bands from 500nm to 700nm and lower energy bandgap of 1.72eV for P1 and 1.77eV for P2. The electronic energy levels of the polymers were measured by electrochemical cyclic voltammetry. The HOMO and LUMO energy levels of P1 and P2 are at −5.03eV, −5.18eV and −3.39eV, −3.43eV, respectively. The polymers P1 and P2 containing dithienosilole units show lower HOMO and LUMO energy levels, in comparison with other poly(thienylene vinylene) derivatives. [Copyright &y& Elsevier]