Enhancement of Heat Dissipation in LED Using Graphene and Carbon Nanotubes

Enhanced heat dissipation in light emitting diodes (LED) increases its stability and lifetime. Although multilayer graphenes (MGPs) or multi-walled carbon nanotubes (MWCNTs) can enhance the heat dissipation to some extent, better results are obtained when both are used together. Due to the strong π-π bond interaction and van der Waals interaction between the layers, MGPs are prone to stacking and agglomeration, which limits their effective thermal conductivity. The addition of MWCNTs can increase the area of contact between the heat-dissipating coating and the air, and the effect of the MWCNTs on the heat-dissipating coating of the rear of LED is studied by changing the ratio of MGPs to MWCNTs. The ability of two different anionic surfactants to disperse MGPs and MWCNTs for facilitating heat removal was also evaluated. The concentration of the surfactants and the pH value were varied and based on the results, an optimal heat-dissipating coating for LED with excellent thermal conductivity is proposed.