Hierarchical NiO/TiO2 composite structures for enhanced electrochromic durability

• Published in: Thin solid films 2018-10, Vol.664, p.1-5
• Main Authors: Yu, Jung-Hoon, Yang, Hyeeun, Jung, Rak Hyun, Lee, Ji Won, Boo, Jin-Hyo
• Format: Article
• Language: English
• Subjects: Chemical bath deposition; Composite structure; Durability; Electrochromic; Nickel oxide
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2018.07.049

This study presents the fabrication of nickel oxide (NiO) thin films with enhanced electrochromic durability by combining titanium dioxide (TiO2) honeycomb structure. The final structure possesses an hierarchical architecture with a substructure of honeycomb structured TiO2 prepared by liquid phase deposition through polystyrene sphere monolayer template with diameter of 800 nm and a superstructure of porous NiO nanoflake array prepared by chemical bath deposition. Compared to the pure NiO nanoflake film, the composite NiO/TiO2 films exhibits noticeable electrochromic cycling durability (only 25% decrease after 5000 cycles) at 550 nm and fast coloration and bleaching response rate (13.4 and 6.7 s). This improvement in electrochromic properties is due to the rapid dissociation of electrons and photons through the composite structure of the n-type TiO2 core/p-type NiO shell and rapid electrolyte penetration through ordered array geometry with increased surface area. •Hierarchical NiO/TiO2 composite films were achieved by chemical bath deposition.•The NiO/TiO2 composite films exhibits shorten coloring and bleaching response time.•Noticeable improvement of durability for the NiO/TiO2 composite was observed over 5000 cycles.•These P/N composite can enhance the separation of electron and proton by the electric junction field.