Properties of pulsed laser deposited NiO/MWCNT thin films

Abstract

Pulsed laser deposition (PLD) is a thin-film deposition technique, which uses short and intensive laser pulses to evaporate target material. The technique has been used in this work to produce selective solar absorber (SSA) thin film composites of multiwall carbon nanotubes (MWCNT) and nickel oxide (NiO). Whilst most physical vapour deposition techniques require high temperatures to achieve good adhesion between substrate and coating, with PLD it is possible to get excellent adhesionwith the substrate temperature set at room temperature. Selective solar absorbers must have high solar absorptance in the UV-Vis region and a low thermal emittance in the far infra red region to avoid thermal losses. The strength and durability of the thin films are also of critical importance if the coating is to be used in the field, therefore tests have been carried out on samples in the work presented here. It is concluded that: (1) MWCNT/NiOcomposite thin films have been successfully fabricated with the PLD technique, (2) SEM has confirmed that the MWCNT have been decorated with NiO nanoparticles and Raman confirms the formation of a new material with different vibrational properties, (3) the solar absorptance starts by increasing, gets constant before starting to reduce again, and (4) it has been found that the thin films adhere to the substrate and that the accelerated ageing tests has no significant impact on the optical properties of the thin composite material thin film coating.