Hydrophobic Anti-Reflective Coating of Plasma-Enhanced Chemical Vapor Deposited Diamond-Like Carbon Thin Films with Various Thicknesses for Dye-Sensitized Solar Cells

Diamond-like carbon (DLC) thin films, prepared by a radio frequency plasma-enhanced chemical vapor deposition (PECVD) system, were investigated for application as an anti-reflective coating (ARC) for dye-sensitized solar cells (DSSCs) with a change in film thickness. The strength of the Raman spectrum, G-peak position, and ID/IG ratio, related to sp3 bonds in the DLC thin films, is directly attributed to some tribological properties including surface roughness, hardness, elastic modulus, friction coefficient, and contact angle. Some optical properties, such as transmittance, refractive index, and absorption coefficient, were examined after changing the thickness of DLC thin films. The optimal short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF) values were obtained for the significantly improved conversion efficiency (CE) from 4.92% to 5.35% in the 60 nm thick PECVD DLC ARC for DSSCs with hard and hydrophobic surfaces.