Control of Structure and Film Thickness Using Spray Layer-by-Layer Method: Application to Double-Layer Anti-Reflection Film

Abstract

The recently developed practice of spraying solutions onto a substrate to fabricate thin films via layer-by layer (LBL) method has been further investigated and extended. We successfully fabricated double-layer anti-reflection (AR) thin films with high- and low-refractive-index layers by the spray layer-by-layer (spray-LBL) method. For the deposition of a high-refractive-index layer, layers of poly(diallyldimethylammonium chloride) (PDDA) and titanium(IV) bis(ammoniumlactato) dihydroxide (TALH) were alternatively assembled. The average thickness of (PDDA/TALH) was determined to be 7 nm and the refractive index was n=1.76 at 550 nm. Poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) layers were assembled on the high-refractive-index layer for the deposition of the low-refractive-index layer. The average thickness of (PAH/PAA) was determined to be 14 nm and the refractive index was n=1.48 at 550 nm. This AR thin film showed the maximum transmittance (94.5%) and the minimum reflection (0.5%) at approximately 550 nm in wavelength.