Preparation of Cu2ZnSnS4 thin films by using electrospray method: Experimental and modeling approach on film growth

• Cu2ZnSnS4 (CZTS) thin films were prepared by electrospray deposition method at atmospheric pressure.
• The film post-annealed at 663 K for 1 h showed the best crystallinity and optimal band-gap energy.
• The wetting properties during electrospray process were performed through a numerical study.
• The relationship between the volume of a droplet on the substrate and the area of the deposited film was performed by mathematical model and experimental data.

Cu2ZnSnS4 (CZTS) thin films were deposited on glass substrate by using an electrospray method and an annealing process for improving the crystallinity and the morphology of the prepared films was performed. To investigate the relationship between the volume of a droplet on the substrate and the area of the deposited film, a numerical study on the wetting properties was performed for the first time in electrospray research, so a mathematical model to predict the shape of the droplet on the substrate with respect to temperature was developed. According to the simulation results, the deposition area by the single droplet was accurately predicted compared with the experimental data. In addition to the numerical approach, the properties of the films were experimentally analyzed. Consequently, the film with the best crystallinity, was synthesized by 60 min electrospraying deposition and followed by the annealing at 663 K. This film showed an optical band gap of 1.55 eV. Thus, both experimental and modeling analysis will suggest a new process to produce inorganic thin films.