Enhanced Light Absorptivity of Carbon Nanotube Composite Coatings with Conical Micro-structure

Abstract

Black coatings with high light absorptivity are of great importance for many applications. It is concluded that the morphology of the coatings can greatly affect the absorptivity. Here, the influence of the morphology in controlling the light absorptivity of carbon nanotube composite coating has been studied. Carbon nanotube composite films are fabricated by painting carbon nanotube- cyanoacrylate slurry on the substrate. Uniform micro-cones on the surface of the coatings were fabricated by laser irradiation in air. The angles of the microcones obtained could be controlled by changing the energy density of the laser pulses. The spectral absorptivity measurement from 0.25 μm to 2 μm shows that the carbon nanotube composite coatings with such conical micro-structure have enhanced light absorptivity. It is also shown that the conical micro-structure with smaller cone angles exhibited much higher light absorptivity. It is proposed that carbon nanotube composite film being irradiated by laser is a simple and efficient method to fabricate black coatings with high light absorptivity.