Optimizing ultrasonic mist vapor deposition parameters toward facile synthesis of tungsten oxide nanofibers

Thanks to its high surface area, excellent condition for light absorption and scattering and suitable charge transport directions, nanofibrous morphology is a fascinating candidate for many important application fields. Herein as the first report, Tungsten oxide (WO2.92) thin films have been prepared via ultrasonic mist vapor deposition (UMVD) method. The effects of important growth parameters namely substrate-nozzle distance (D = 3, 5 and 8 cm), deposition time (t = 3, 6 and 18 min), substrate temperature (T-s = 130, 200 and 400 degrees C) and angle (theta = 0, 25 and 45 degrees) on surface morphology of prepared thin films were investigated systematically. The analyses results revealed that Ts and 0 played more determining roles affecting on tungsten oxide thin film morphology. Interestingly, very clear and obvious tungsten oxide nanofibers were deposited uniformly over the whole of substrate surface when high deposition time and angle (t = 18 min, theta = 45 degrees) and mild substrate temperature (T-s = 200 degrees C) were utilized. The average diameter of grown nanofibers increased from 297 nm for theta = 0 degrees to 429 nm for 0 = 45 degrees. No fibrous morphology was observed for the layers prepared with both low T-s = 130 and high T-s = 400 degrees C. Considering all of the results, a mechanism was proposed describing how the nanofibers were grown via UMVD method. obtaining fine tungsten oxide nanofibers via such a simple method is very interesting to use them as electrochromic coatings, sensors, photoelectrochemical electrodes etc.

Automated summary

Tungsten oxide nanofibrous thin films were successfully prepared via ultrasonic mist vapor deposition method. The effects of different growth parameters on the surface morphology of the films were investigated, revealing that substrate temperature and angle played crucial roles in the formation of tungsten oxide nanofibers. Under suitable growth conditions, uniform and clear tungsten oxide nanofibers could be deposited.