Advancements in TiO2-based multi-composite photochromic materials: A review

With the rapid development in the field of smart materials, photochromic materials have a wide range of application prospects. Titanium dioxide (TiO₂), as a common semiconductor material, is widely studied in the preparation of photochromic materials. However, a single TiO₂ material has some limitations in photochromic performance. Therefore, the introduction of a multi-faceted composite approach becomes an important way to enhance the performance of the materials. The aim of this paper is to review the latest research progress of TiO₂-based multi-composite photochromic materials and to explore the effects of different composite systems on photochromic properties. This paper first introduces the basic properties and application areas of TiO₂ photochromic materials, which provides a basis for the subsequent discussion. Second, TiO₂-based binary composite photochromic materials are classified and discussed in detail, including TiO₂/metal, TiO₂/metal oxide, and other TiO₂-based binary composites. Then the research progress of TiO₂-based ternary composite photochromic materials is discussed. Finally, the future development direction of TiO₂-based multi-composite photochromic materials is envisioned. This paper serves as a reference for future research on composite photochromic materials, promotes the development of photochromic materials in practical applications, and facilitates progress and innovation in the field of smart materials.