Vanadium pentoxide (V2O5) thin films are greatly favorable materials for optoelectronic applications owing to their broad optical band gap, considerable thermal and chemical stability. In this work, the influence of thermal treatment on the microstructure related to the nonlinear optical, optical limiting and phase transition behaviors of the V2O5 thin films produced via ultrasonic spray deposition method onto FTO/glass substrates were systematically examined by Z-scan experiments. Homogenous and crack-free V2O5 thin films with a nanorod morphology were obtained after thermal treatment. OA Z-scan results indicated that the whole V2O5 thin films exhibited defect-assisted nonlinear absorption behavior, and annealing at 450 °C increased the nonlinear absorption and optical limiting behavior. Higher annealing temperatures, in contrast, led to a decrease in these behaviors. CA Z-scan trace showed that the sign of nonlinear refractive index inverted by thermal process. The phase transition was associated with crystalline V2O5 thin films via thermall process. V2O5 thin films annealed at 450 ºC could be promising optical limiters within 500 - 700 nm visible range due to their high linear transmittance (> 80 %) and low optical limiting threshold.

https://doi.org/10.1002/adem.202100468