Nucleate boiling enhancement on hybrid graphene-nanoplatelets/carbon nanotubes coatings for light-emitting diode cooling

This study explores the remarkable enhancement of light-emitting diode (LED) cooling through nucleate boiling using hybrid coatings of graphene-nanoplatelets (GNP) and carbon nanotubes (CNT). The introduction of oxygenated functional groups in the cured GNP and CNT coatings fosters improved hydrophilicity, promoting water intercalation within the nanostructures. The hybrid cured GNP/CNT coating demonstrates superior nucleate boiling performance compared to individual cured GNP and CNT coatings, owing to complementary mechanisms. Cured CNT facilitate efficient water permeation by enabling water molecules to infiltrate through their inner cores and intertwining tube spaces, while cured GNP offer an escape route for trapped water molecules and absorbed latent heat due to their layer-by-layer arrangement of graphene sheets with broadened interlayers. As compared to the bare copper surface, the LED cooled using the hybrid cured GNP/CNT coating exhibits a maximum temperature drop of 20.7 °C and an enhancement up to 1212 % in heat transfer coefficient, surpassing the cured GNP and CNT coatings. Moreover, the hybrid cured GNP/CNT coating improves the LED illuminance by 16.6 %, validating its potency in improving cooling performance. These findings highlight the potential of GNP/CNT hybrid coatings in advancing nucleate boiling cooling technologies and offer valuable insights into optimizing LED performance for high-quality lighting solutions.