Enhancing the Photovoltaic Properties via Incorporation of Selenophene Units in Organic Chromophores with A 2 -π 2 -A 1 -π 1 -A 2 Configuration: A DFT-Based Exploration.

Currently, polymer organic solar cells (POSCs) are widely utilized due to their significant application, such as low-cost power conversion efficiencies (PCEs). Therefore, we designed a series of photovoltaic materials ( D1, D2, D3, D5 and D7 ) by the incorporation of selenophene units ( n = 1-7) as π 1 -spacers by considering the importance of POSCs. Density functional theory (DFT) calculations were accomplished at MPW1PW91/6-311G (d, p) functional to explore the impact of additional selenophene units on the photovoltaic behavior of the above-mentioned compounds. A comparative analysis was conducted for designed compounds and reference compounds ( D1 ). Reduction in energy gaps (∆E = 2.399 - 2.064 eV) with broader absorption wavelength (λ max = 655.480 - 728.376 nm) in chloroform along with larger charge transference rate was studied with the addition of selenophene units as compared to D1 . A significantly higher exciton dissociation rate was studied as lower values of binding energy (E b = 0.508 - 0.362 eV) were noted in derivatives than in the reference (E b = 0.526 eV). Moreover, transition density matrix (TDM) and density of state (DOS) data also supported the efficient charge transition origination from HOMOs to LUMOs. Open circuit voltage ( V oc ) was also calculated for all the aforesaid compounds to check the efficiency, and significant results were seen (1.633-1.549 V). All the analyses supported our compounds as efficient POSCs materials with significant efficacy. These compounds might encourage the experimental researchers to synthesize them due to proficient photovoltaic materials.