Optimization of Sb₂S₃ Nanocrystal Concentrations in P₃HT: PCBM Layers to Improve the Performance of Polymer Solar Cells

In this study, polymer solar cells were synthesized by adding Sb₂S₃ nanocrystals (NCs) to thin blended films with polymer poly(3-hexylthiophene)(P₃HT) and [6,6]-phenyl-C61-butyric-acid-methyl-ester (PCBM) as the p-type material prepared via the spin-coating method. The purpose of this study is to investigate the dependence of polymer solar cells' performance on the concentration of Sb₂S₃ nanocrystals. The effect of the Sb₂S₃ nanocrystal concentrations (0.01, 0.02, 0.03, and 0.04 mg/mL) in the polymer's active layer was determined using different characterization techniques. X-ray diffraction (XRD) displayed doped ratio dependences of P₃HT crystallite orientations of P₃HT crystallites inside a block polymer film. Introducing Sb₂S₃ NCs increased the light harvesting and regulated the energy levels, improving the electronic parameters. Considerable photoluminescence quenching was observed due to additional excited electron pathways through the Sb₂S₃ NCs. A UV-visible absorption spectra measurement showed the relationship between the optoelectronic properties and improved surface morphology, and this enhancement was detected by a red shift in the absorption spectrum. The absorber layer's doping concentration played a definitive role in improving the device's performance. Using a 0.04 mg/mL doping concentration, a solar cell device with a glass /ITO/PEDOT:PSS/P₃HT-PCBM: Sb₂S₃:NC/MoO₃/Ag structure achieved a maximum power conversion efficiency of 2.72%. These Sb₂S₃ NCs obtained by solvothermal fabrication blended with a P₃HT: PCBM polymer, would pave the way for a more effective design of organic photovoltaic devices.