Sustainable Conjugated Polymer Synthesis in OPV: A Case Study from Conventional to Flow and Microwave-Assisted Synthesis

Continuous flow synthesis and microwave-assisted synthesis represent two sustainable and efficient methods for polymer production aligned with green chemistry principles, compared to conventional polymer synthesis. Here we present a case study of poly(4,4-dioctyldithieno(3,2-b:2′,3′-d)silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl (PSBTBT), a low band-gap electron-donating polymer for organic photovoltaics (OPVs). The PSBTBT Stille cross-coupling polymerization conditions were optimized by comparing different synthetic methods: conventional, flow, and microwave. To assess the impact of the different synthetic methods, detailed molecular and spectroscopic characterization, highlighting both the differences and similarities within the methodologies, was performed with several techniques, such as GPC, UV-Vis, PL, and NMR