Synthesis and investigation of optical, electrochemical, and thermal properties of thiophene and thieno[3,2-b]thiophene linked with modified 2,4-thiazolidinedione copolymers for optoelectronic applications

Two new copolymers of thiophene, thieno[3,2-b]thiophene as donor linked with structurally modified 2,4-thiazolidinedione as acceptor at the side chain were synthesized by an effective Stille polycondensation process. The polymers were then characterized by different spectral techniques, size-exclusion chromatography, thermal stability, XRD, and SEM analyses. Obtained copolymers were thermally stable up to 325 °C, having good solubility and film forming property with common organic solvents. Optical band gaps were arrived at 1.96 and 1.99 eV using the onset of film absorption of PTMEHT-T (P1) and PTMEHT-TT (P2). Solvatochromic properties of P1 and P2 were systematically examined and discussed using the Lippert-Matagas plot. Electrochemical investigations showed that the P1 and P2 possess HOMO and LUMO energy levels of − 5.67, − 5.64 eV and − 3.35, − 3.61 eV, respectively. In addition, energy levels are calculated using the DFT method. Obtained results revealed that the copolymers could be one of the capable materials for optoelectronic device applications and may lead to desirable improvements in performance.