Optoelectronic Properties of 4,6-Dihydro-5H-Thieno [2,3-B]Pyrrol-5-One Based Conducting Polymers for Photovoltaic Applications

Energy materials have great demand in the global energy market today. Renewable sources of energy materials are sustainable sources of energy materials that have many advantages over traditional materials. Metal-based solar cells are first-generation materials that are commercialised due to their high efficiency. However, the high cost of these materials hinders their wide applications. In recent times organic polymers have attained a lot of interest due to their low cost, flexibility and broad absorption. This research reports a new polymer (4Z)-4-(thiophene-2- ylmethylidene)-4,6-dihydro-5H-thieno[2,3-b] pyrrole-5-one synthesised using Aluminium substituted catalyst which achieved high yield at ambient temperature. Separate polymerisation of the produced monomer was done using thiophene functionalised with bis (trimethylstannyl) to get polymer P1 which showed broad absorption in UV-visible region between 620 to 625nm showing Highest Occupied Molecular Orbital (HOMO) energy levels that are low lying. The heterojunction solar cells based on the new polymers were fabricated and tested. Based on the novel polymer, the solar cell devices demonstrated a remarkably high power conversion efficiency of 6.6%, an open circuit voltage (VOC) of 0.63, a fill factor of 0.52 and a short circuit current density (Jsc) of 6.3. For Polyvinyl Chloride (PVC) applications, the produced polymers are hence promising candidates. Furthermore, future studies involve doping of suitable metals like copper and samarium to the polymer to enhance the efficiency of the photovoltaic cells.