Oxygen-etchant-promoted synthesis of vertically aligned graphene arrays in a Joule heater and defogger

Abstract

Vertically aligned graphene arrays (VAGAs), as a vertical ordering generated via the accumulation of longitudinally grown two-dimensional graphene with excellent porosity and large specific surface area, were suggested as candidates for application in thermal management. However, when using the current strategy of preparing VAGAs, amorphous carbon layers appear as interfacial layers, diminishing the performance of such VAGAs-based devices. Herein, the direct approach of superb thermal conductivity, super-hydrophobicity, and the use of low-resistance VAGAs on glass is reported using the combination of UV/ozone treatment and in-situ plasma-enhanced chemical vapor deposition (PECVD). The use of a UV/ozone-etchant can reduce the amorphous carbon species on the target substrate and promote VAGAs nucleation. The growth mechanism therein is investigated and elucidated. Direct synthesis of VAGAs on glass can combine the complementary features of traditional glass and modern materials. Based on the superb vertical thermal/electrical conductivity, VAGAs on functional glass, thus formed with VAGA/glass and can act as a heater and defogger, the benefits of this VAGA defogger lie in its ultrafast defogging time for relatively low input voltages and unique defogging stability, reaching a saturation temperature of up to 160 °C when 25 V was applied for 16 s. Our study is conducive to investigation of the direct synthesis of VAGAs on glass and its potential importance in thermal management.