<p>Luminescent down-shifting (LDS) materials, which absorb ultraviolet (UV) radiation and re-emit visible photons, are being explored as promising coatings for enhancing solar cell efficiency. This study investigates the effects of spin-coated YVO₄:Eu³⁺ LDS layer on the performance of commercial silicon (Si) solar cells. The YVO₄:Eu³⁺ nanoparticles were successfully synthesized using both combustion and hydrothermal methods, each producing high-purity powders with well-defined crystallinity. Photoluminescence results confirmed the effective UV-to-visible photon conversion of the synthesized powders when used as an LDS material. UV–Vis spectroscopy revealed enhanced absorption in both the UV and visible regions for LDS-coated cells. Device performance was significantly influenced by the synthesis method and the concentration of the precursor solution. At the optimal concentration, the combustion-synthesized YVO₄:Eu³⁺ (Comb-2:10) improved power conversion efficiency (PCE) by ~ 4.45% (from 8.97 to 9.37%) compared to the uncoated cell. However, higher concentrations led to reduced performance due to particle agglomeration, non-uniform film coverage, and increased light scattering. In contrast, the hydrothermal-synthesized YVO₄:Eu³⁺ precursor enabled the formation of a uniform, transparent, and defect-free LDS layer at its optimal concentration (Hydro-2), effectively enhancing antireflection and down-shifting performance. The champion device (Hydro-2) demonstrated a short-circuit current density (J_SC), open-circuit voltage (V_OC), and fill factor (FF) of 32.57 mA cm⁻², 0.57 V, and 0.51, respectively, corresponding to a PCE of 9.47%, representing a 5.6% improvement over the uncoated cell and a 1.1% gain over Comb-2:10. These findings highlight the strong potential of spin-coated YVO₄:Eu³⁺ layers as effective antireflection and down-shifting coatings for enhancing photovoltaic device efficiency.</p>