University of Tehran Journal of Solar Energy Research 2588-3097 11 1 2026 01 01 Boosting Sustainable Dye-Sensitized Solar Cells (DSSCs) Performance via Copper-Doped Manganese Sulfide Nanoparticles: A Comparative Study 2891 2902 106105 10.22059/jser.2026.405234.1663 EN Ahmed Nsaif Jasim Department of Physics, College of Science, University of Diyala, Diyala, Iraq. Journal Article 2025 10 29 This study demonstrates a significant enhancement in the performance of sustainable dye-sensitized solar cells (DSSCs) through the integration of copper-doped manganese sulfide (MnS:Cu) nanoparticles as photoanodes. Undoped, 1% Cu, and 3% Cu-doped MnS nanoparticles were synthesized via a facile co-precipitation method. X-ray diffraction confirmed a nano-crystalline structure, with the crystallite size on the (200) plane increasing from 12.60 nm (undoped) to 14.37 nm (3% Cu). Critically, copper doping induced a reduction in the optical band gap from 3.4 eV to 3.2 eV, enhancing light harvesting. Morphological analysis revealed a transformation from large, flat islands (undoped) to a uniform layer of smaller, spherical nano-grains (~43 nm for 3% Cu), which improved dye loading and light scattering. Consequently, the power conversion efficiency of the fabricated DSSCs increased substantially with doping concentration, yielding 0.455%, 0.624%, and 0.905% for undoped, 1% Cu, and 3% Cu-doped MnS-based cells, respectively, under standard illumination (100 mW cm⁻², AM 1.5G). This work establishes Cu-doping as a highly effective strategy for tailoring the properties of MnS nanoparticles for efficient solar energy conversion. https://jser.ut.ac.ir/article_106105_27cdccc5f8c11ddf047d03c22b827308.pdf