Block copolymer-templated synthesis of highly organized mesoporous TiO2-based films and their photoelectrochemical applications

Over the last decade, mesoporous TiO2 nanocrystalline films have been intensively investigated not only for fundamental research interest but also for technological applications. This critical review summarizes recent progress of the block copolymer-templated highly organized mesoporous TiO2-based films prepared via an evaporation-induced self-assembly (EISA) process and their photoelectrochemical applications. With a brief introduction to the principle of block copolymer self-assembly and EISA process, control of the cooperative self-assembly between Ti species and block copolymer in the sol solution as well as in the deposited films, aging under a controlled humid environment, and subsequent thermal treatment is described. Key experimental parameters for the preparation of highly organized mesoporous TiO2 films are analyzed. Applications of mesoporous TiO2-based films in photocatalytic reactions, catalytic chemical synthesis, dye-sensitized solar cells, and electrochromic and photochromic devices are discussed. The synthesis-component-structure-property relationship in mesoporous TiO2-based films is highlighted, and the perspectives in this rapidly developing field are suggested.