Abstract <p>Ongoing research efforts are aimed at developing bifacial dye-sensitized solar cells (DSSCs) that are both economically viable and high-performance. In this investigation, molybdenum disulfide-decorated biomass-derived carbon from waste papaya straws (MoS₂@PS) was synthesized via a hydrothermal technique, and then subsequently subjected to annealing at various temperatures, referred to as PS26, PS27, and PS28. Annealing MoS₂ -decorated PS resulted in an increase in surface area which was confirmed using Brunauer–Emmett–Teller measurements, revealing type IV isotherms with an H3 hysteresis loop showing the mesoscopic nature of PS28. The maximum recorded photovoltaic conversion efficiency was approximately 6.85% for the PS28 composite counter electrode (CE), highlighting its potential as a platinum-free alternative. Moreover, cyclic voltammetry and Tafel polarization studies confirmed the superior electrocatalytic activity of the MoS₂@PS CE in the reduction process of triiodide ions (I₃⁻). Studies on transmittance were conducted to validate the bifacial characteristics of DSSCs. The results from electrochemical impedance spectroscopy indicate that the MoS₂@PS CE-based DSSCs exhibit rapid charge transfer at the electrode/electrolyte interface, with a resistance of <i>R</i>_CT = 24.27 Ω for the PS28 counter electrode. The favourable attributes of optimal conversion efficiency, high transmittance, ease of preparation, rapid charge transfer, and affordability suggest that MoS₂@PS counter electrodes hold significant potential for applications in DSSCs.</p> Graphical Abstract <p></p>