Optimized synthetic conditions of structural colored TiO<sub>2</sub>/SiO<sub>2</sub> multilayers

Sol–gel synthesis of TiO2/SiO2 multilayers was studied for application to structural color materials. The purpose this study is achieve crack-free thick films, which are indispensable high reflectance and vividness. We investigated the effect polymer additives heating conditions on fracture TiO2 gel films. critical cracking thickness increased more than three-fold at maximum by adding poly(vinyl pyrrolidone) (PVP) precursor sols using a low rate. From stress measurement based Stoney’s model, we found that addition PVP extensively reduced residual stress, proving mechanism suggested so far hinders evolution Ti–O network reduces drying stress. Under restriction thickness, multilayered films flakes were prepared as feasibility test coloration. A high-order interference condition used optical design, allows us obtain narrow spectral peaks primary colors light. Theoretically expected reflection spectra corresponded blue green attained five-layered