Water Vapor Barrier Performance of Printable Photodensified Polysilazane and Wavelength Dependence in Light Irradiation

Abstract

Gas barrier technology for water vapor is utilized across various industries. In this study, a reaction was used to form dense SiN_x films with soluble Polysilazane (PHPS: perhydropolysilazane) as a precursor and with irradiation of 172 or 222 nm light to fabricate water vapor barrier films. In 172 nm light irradiation, the high absorption coefficient of PHPS caused photodensification at the film surface, resulting in high water vapor barrier performance (one unit: 2.2×10^-4 g/m²/day, three units: 5.0×10^-5 g/m²/day). Conversely, the irradiation with 222 nm light resulted in densification inside the film due to PHPS's low absorption coefficient. The resulting barrier performance was low, suggesting that this was caused by the absence of localized densification. Nevertheless, combining 172 nm and 222 nm light improved both crack resistance and barrier performance. This achievement represents significant technology capable of resolving the trade-off between photodensification and crack resistance.