Synergistic effects in the TiO2@ZnO/MoSe2 ternary composite photoanode for enhanced solar cell efficiency

Abstract

In this study, the ternary composites of two-dimensional transition-metal dichalcogenides, specifically molybdenum selenide (MoSe₂) decorated with titanium dioxide and zinc oxide (TiO₂@ZnO/MoSe₂), were synthesized using the hydrothermal method. The FE-SEM image of TiO₂@ZnO/MoSe₂ ternary composite exhibited nanoparticles with an embedded crystalline nature. HR-TEM image revealed a nanoparticle-encased multicrystalline structure. The AFM analysis of the TiO₂@ZnO/MoSe₂ ternary composite photoanode displayed a highly textured and rough surface. Furthermore, X-ray studies indicated that the as-prepared TiO₂@ZnO/MoSe₂ ternary composite photoanode contains the anatase phase, with the predominant crystalline orientation being (110). Raman results confirmed the presence TiO₂, ZnO, and MoSe₂ in the ternary composite. UV–visible spectroscopy revealed absorption peaks at 248 nm, 226 nm, and 630 nm, corresponding to TiO₂, ZnO, and MoSe₂, respectively. The TiO₂@ZnO/MoSe₂ composite photoanode showed an electrical conductivity of 5.63 × 10⁻⁴ S cm⁻¹ at room temperature. Additionally, dye-sensitized solar cells with the TiO₂@ZnO/MoSe₂ ternary composite photoanode achieved a notably higher efficiency (9.13 %) than those with TiO₂@MoSe₂ and ZnO@MoSe₂ photoanodes (7.35 % and 6.27 %, respectively). The proposed ternary composite consistently outperformed previously reported TiO₂-based photoanodes such as nitrogen-doped TiO₂ nanoparticles/nanotubes, Pt-doped TiO₂ nanotubes on the Ti mesh, and carbon nanotube–doped TiO₂ nanorods (efficiencies of 2.53 %, 5.60 %, and 2.30 %, respectively). After a 30-day stability test, the TiO₂@ZnO/MoSe₂ ternary composite photoanode showed the efficiency of 8.47 %. This suggests that the TiO₂@ZnO/MoSe₂ composite is a promising photoanode material for high-performance dye-sensitized solar cells.