Inkless printing and advanced dynamic information anti-counterfeiting via photochromic system based on solid-state Zr/Ti-MOF@WO3 heterojunctions

Given that heterojunction engineering is an effective method for improving the separation efficiency of photoexcited electrons in WO3-based photochromic systems, a series of solid-state photochromic Zr/Ti-MOF@WO3 heterojunctions prepared via a facile hydrothermal strategy, where Zr/Ti-MOF with photosensitivity and chemical stability was selected as template to load WO3. Zr/Ti-MOF@WO3 heterojunctions were verified as nanoparticles filled with thin layer structure and WO3 was diffused into the Zr/Ti-MOF planar. The appropriate conductive band energies facilitate the transport of photostimulated electrons from Zr/Ti-MOF to WO3, resulting in a fast photresponse in color changes (it only takes 1 s). In addition, a carrier for information storage and data dynamic encryption was developed on the basis of the photochromic Zr/Ti-MOF@WO3 heterojunctions. This work presents a promising way to improve the electron/holes separation efficiency by constructing unique heterojunctions and further explore novel WO3-based photochromic systems and broaden their applications in rewritable media and data security.