Sol-gel synthesis of transparent conductive ZnO films from zinc salicylate solution
The development of low temperatures sol-gel methods for producing thin oxide films contributes to the development of the direction of creating photocells based on zinc oxide applied not only to glass, but also to transparent heat-resistant polymeric materials to create flexible solar cells. This work is devoted to the low-temperature preparation of zinc oxide films from a film-forming solution (FFS) based on zinc salicylate. By viscometry and IR spectroscopy it was established that the FFS contains ZnSal2 and the solution is suitable for obtaining films with stable properties within a day from the day of its preparation. Thermal destruction of FFS proceeds in three stages and ends at a temperature of 350°C with the formation of zinc oxide with the wurtzite crystal structure. An increase in the annealing time of the films from 24 to 48 hours makes it possible to form a more crystalline structure of the oxide, which leads to an increase in the conductivity of the thin-film material on both silicon and glass substrates while maintaining the transparency coefficient in the visible region of the spectrum (75-78%). An increase in the thickness of ZnO films leads to a violation of their continuity (two and three-layer films contain dendro-like macro defects-cracks) and a decrease in resistance, as well as to a decrease in their transparency (T = 60%). Contribution of the authors: the authors contributed equally to this article. The authors declare no conflicts of interests.