Synergistic Incorporation of 2D Graphitic Carbon Nitride into Bimetal Oxide Photoanodes Towards Higher-Performance DSSCs

This study aims to develop cost-effective and efficient dye-sensitized solar cells (DSSCs) by synthesizing a novel NiMoO₄/g-C₃N₄ hybrid composite material using a straightforward ultrasonic-assisted hydrothermal method. The investigation of optical properties through UV-visible absorption spectroscopy revealed distinct band gap energies of 2.65 eV for NMO-GN0, 2.50 eV for NMO-GN5, 2.42 eV for NMO-GN7, and 2.30 eV for NMO-GN10, underscoring the tunable nature of the synthesized materials. The research extended to the evaluation of power conversion efficiency (PCE) in DSSCs employing NMO-GN as photoanode materials. Remarkably, the PCE exhibited significant sensitivity to the concentration of graphitic carbon nitride in NiMoO₄. In detail, the manufactured DSSCs demonstrated an impressive PCE of 8.21% for NiMoO₄/GN, notably outperforming bare NiMoO₄ with a PCE of 2.75%. This enhancement is attributed to the reduction in electron recombination, improved incident photon-to-current conversion yield due to expedited charge collection, and enhanced dye sensitization. Furthermore, the synergistic effect between NiMoO₄ and the graphene-based material offered an extensive active pathway, facilitated by their substantial surface area (104.8 m²/g) and sizable pore size (38.82 nm). The enhancement in the photoelectric conversion properties of NiMoO₄/g-C₃N₄ primarily stems from the increased porosity and textural changes within the photoelectrodes induced by graphene incorporation. A detailed mechanism for this improved efficiency was discussed, incorporating insights from electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), providing a comprehensive understanding of the enhanced performance achieved in these advanced DSSCs. This work presents a promising approach to address the challenges of cost-efficiency and improved performance in DSSCs, contributing to the advancement of sustainable solar energy technologies.