<p>This research endeavors to examine the performance degradation of solar photovoltaic (PV) systems induced by temperature variations and introduces a ternary hybrid phase-change material (PCM) aimed at improving thermal management. The formulated PCM is predicated on Glauber’s salt (Na₂SO₄·10H₂O) synergistically augmented with graphene (Gr) flakes and aluminum oxide (Al₂O₃) nanoparticles to alleviate phase segregation and supercooling while enhancing thermal transfer efficiency. In contrast to traditional binary PCM systems, wherein graphene predominantly augments thermal conductivity, the inclusion of Al₂O₃ nanoparticles within the ternary composite serves as an efficacious heterogeneous nucleation site, thereby mitigating supercooling and stabilizing the phase-transition dynamics, while graphene establishes uninterrupted conductive pathways that expedite heat diffusion throughout the PCM matrix. An outdoor experimental assessment was performed on three distinct PV configurations: a reference PV module devoid of PCM (PV-1), a binary PCM-integrated module (PV-2), and a ternary composite PCM-integrated module (PV-3). The findings indicate that PV-3 attains a maximum reduction in operating temperature ranging from 3 to 4&#xa0;°C and an enhancement in electrical efficiency between 2 and 3% when juxtaposed with PV-1, while simultaneously demonstrating superior thermal stability and conductivity in comparison with PV-2. Material characterization techniques, including x-ray diffraction (XRD), scanning electron microscopy (SEM), and thermal conductivity analysis (TCA), corroborate the stable dispersion of Al₂O₃ nanoparticles and the establishment of a graphene-assisted conductive network. The results elucidate that the synergistic mechanisms of nucleation enhancement and conductive network formation within the Gr + Al₂O₃ composite proficiently modulate the operating temperature of photovoltaic systems, thereby presenting a dependable and scalable passive cooling strategy for photovoltaic applications.</p>