Preparation and black-white electrochromic performance of the non-contact ZnO@NiO core-shell rod array

Abstract

In this paper, the non-contact ZnO@NiO core-shell rod array films with black-white electrochromic performance were designed and constructed by electrochemical deposition method. The blank porous NiO films were also prepared for comparison. The morphology, component and microstructure of the films were characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM). And their electrochromic (EC) performance was examined. The results show that the ZnO transition layer presents a hexagonal rod array nature, which is approximately perpendicular to the surface of substrate, thus, offered a three-dimensional frame for the growth of porous NiO. The ZnO@NiO film is composed of a large number of non-contact core-shell rods. The introduction of ZnO rod array transition layer not only led to the improvement of film/substrate connection but also resulted into the high EC performance including sharp black-white contrast, rapid switch speed and good stability. The heterojunction and P-N junction formed at the SnO2/ZnO/NiO interfaces might also play a role in the EC performance.