Multicolor Electrochromic Film Based on TiO2@Polyaniline Core/Shell Nanorod Array

The TiO2@PANI core/shell nanorod array is prepared by the combination of hydrothermal and electro-polymerization methods. A significant optical modulation (57.6% at 700 nm), high coloration efficiency (37.1 cm2 C–1), and good cycling performance (62.1% after 1000 cycles) are achieved for the TiO2@PANI core/shell nanorod array. The improved electrochromic properties are mainly attributed to the core/shell structure, formation of the donor–acceptor system, and the porous space among the nanorods, which can reduce the oxidation potential, make the ion diffusion easier and provide larger surface area for charge-transfer reactions. The data indicate great promise for the TiO2@PANI core/shell nanorod array as a potential multicolor electrochromic material.