Passive thermal management of photovoltaic modules using graphene-enhanced thermal interface and fin-assisted natural convection

Photovoltaic (PV) modules experience substantial efficiency degradation under elevated operating temperatures, yet passive cooling strategies in the open literature predominantly target either external convection enhancement (fins, heat sinks) or material modification approaches applied mainly in forced-flow PVT or nano-PCM systems. A key unresolved gap remains the simultaneous mitigation of interfacial conduction resistance and natural-convection limitation, which together dominate the thermal pathway of standalone PV modules operating without auxiliary subsystems. This study addresses this innovation by experimentally demonstrating a dual-scale passive thermal management architecture that integrates graphene nanoplatelet (GNP)–doped thermal interface paste with longitudinal aluminum fins under purely outdoor natural-convection conditions. Three configurations were tested: a reference module (PV1), a finned module with conventional paste (PV2), and a finned module with 0.5 wt% GNP paste (PV3). Back-surface temperature monitoring and statistical analysis (median, variance, t -test, α = 0.05) confirmed that PV3 achieved a statistically significant temperature reduction relative to PV1 and PV2. This translated into the highest electrical output (23 W), module efficiency (15.8%, +2.6 percentage points vs. PV1), normalized power output efficiency (68–70%), and performance ratio (0.88). The results show that nanoscale phonon-assisted heat spreading at the interface unlocks the full convective potential of passive fins, lowering the overall thermal resistance network without airflow, PCM storage, or parasitic energy consumption. The work establishes a new category of nanomaterial-enabled, energy-autonomous PV cooling, with direct relevance to remote, rooftop, and off-grid solar applications.