Uniform anti-reflective films fabricated by layer-by-layer ultrasonic spray method

Abstract Herein, a layer-by-layer (LBL) ultrasonic spray method was developed and used to successfully fabricate anti-reflective (AR) multilayer thin films. For the chemical and physical deposition of the AR thin film, layers of poly(diallyldimethylammonium chloride) (PDDA) and SiO2 nanoparticles were alternately deposited, producing a film that exhibited a uniform surface, low roughness, and high transmittance. The average thickness of each (PDDA/SiO2) bilayer was determined as 10–15 nm, and the refractive index was n=1.28 at a wavelength of 628 nm, while exhibiting a 99% transmittance in the visible range. This LBL method using the ultrasonic spray technique is effective in controlling film characteristics such as structure, transmittance, refractive index, roughness, and film thickness. The ultrasonic spray LBL technique can be valuable for the medical industry and biomedical fields, which require uniformity in and precise control of thin films.