Spray pyrolysis–derived V₂O₅ thin films as an alternative electrochromic layer for electrochromic devices

In this study, vanadium oxide films were produced in the vanadium pentoxide (V 2 O 5 ) films phase as an alternative electrochromic layer for electrochromic devices by ultrasonic spray pyrolysis technique at 300°C. The V 2 O 5 films were subjected to heat treatment at different temperatures (400°C–450°C–500°C) and the ellipsometric, structural, morphological, optical, and electrical properties of the films were investigated. The optical parameters of the V 2 O 5 films were calculated by different theoretical methods and compared with the ellipsometric results. The average thickness and refractive index values are 172 nm and 2.29, respectively. The V 2 O 5 films showed high optical absorbance in the visible region and bandgap energy values ranged from 2.10 to 2.44 eV. The resistivity and roughness of the films decreased. The average roughness was determined to be 45 nm on average. These results suggest that V 2 O 5 phase films, whose physical properties are improved by annealing without phase change, can be considered as promising electrochromic layers for electrochromic devices applications.