TiO2/PVA Based Composites: Visible Light Activated Rapid Dual-Mode optical Response

Abstract

Photochromic materials with both photochromism and luminescence modulation features hold significant promise for dual-mode optical storage. Nevertheless, challenges arise due to the difficulty in achieving large-scale luminescence modulation, high photochromic contrast, and swift response to low-energy visible light (λ＞450 nm). Leveraging the rapid self-reduction properties of TiO2, a groundbreaking luminescence modulation mechanism was introduced in the TiO2:Sm3+/PVA film, showcasing an impressive luminescence modulation ratio of nearly 100 % within a second, absent photochromic reaction. This study presents a pioneering approach to devise high-performing TiO2/PVA composites. By seamlessly integrating each component, the resultant TiO2-006Au/PVA/MB + RhB film responds to low-power visible-light (λ＞510 nm) at 1.5 W/cm2, achieving over 85 % photochromic contrast and over 98 % luminescence modulation in just 3 s. The incorporation of Au nanoparticles on the TiO2 surface plays a pivotal role in this rapid response, as substantiated by DFT calculations and experimental data. The synergy between MB's photochromic absorption and RhB's emission is essential for high photochromic contrast and luminescence modulation ratios. The cost-effective, rapid-response TiO2/PVA composites with extensive luminescence modulation and photochromic contrast make them ideal candidates for advanced dual-mode optical storage.