Effect of carbon nanotubes and TiN nanoparticles on light absorption property of nanostructured carbon-based coatings fabricated by high-voltage electrostatic spraying technique

In order to acquire high light absorptance in the visible light region to near infrared region economically and environment-friendly, disordered and nanostructured carbon-based coatings were fabricated by using high-voltage electrostatic spraying technique. Carbon microparticles (CMP) and carbon nanotubes (CNT) with tube diameter of 10 nm, 15 nm and 20 nm were chosen as frameworks, carbon nanoparticles (CNP) and TiN nanoparticles were used as loads to fabricate CMP/CNP coating, CMP–CNT/CNP coatings, CMP–CNT/CNP–TiN coatings. The light absorption property and surface morphology of CMP/CNP coating, CMP–CNT/CNP coatings, CMP–CNT/CNP–TiN coatings were compared, then the effect of CNT with different tube diameter and TiN addition on CMP–CNT/CNP coatings and CMP–CNT/CNP–TiN coatings was studied. Results show that the light absorption property of CMP–CNT/CNP coatings using complex framework of CMP and CNT is superior to CMP/CNP coating using single framework of CMP. Not only CNT act as the connector between CMP particles, but also CNT meshwork provides a large number of nano-scale pores, which are very effective to trap lights. When CNT tube diameter of CMP–CNT/CNP coatings is 15 nm, the average light absorptance in the wavelength range of 400–1400 nm reaches the maximum of 96.2%. It is mainly ascribed to the optimal combination of multi-sized optical cavities in CMP–CNT15/CNP coating. After TiN nanoparticles are added, the average light absorptance of CMP–CNT10/CNP–TiN coating, CMP–CNT15/CNP–TiN coating and CMP–CNT20/CNP–TiN coating is 96.6%, 96.4% and 96.3%, respectively. In addition to TiN itself being an excellent plasmonic material, the improved light absorption property of CMP–CNT/CNP–TiN coatings benefits from the modified surface morphology. CMP–CNT/CNP–TiN coatings fabricated by high-voltage electrostatic spraying technique have great application potential in many fields such as solar energy harvesting, infrared imaging, optoelectric devices etc.