Electrochromic performance of chromium-doped Co3O4 nanocrystalline thin films prepared by nebulizer spray technique

Pristine and chromium (Cr)-doped tricobalt tetraoxide (Co3O4) thin films were grown on glass and FTO substrates by nebulized spray pyrolysis technique. The structural, optical and electrical properties of the pristine and Cr-doped Co3O4 films were characterized by X-ray diffraction, scanning electron microscopy, Raman, and four-probe method. The chemical environment of the elements present in the films was identified from energy dispersive X-ray analysis and X-ray photoelectron spectroscopy. The effect of chromium doping on optical constants is discussed in detail. The electrochromic studies reveal that better optical modulation (ΔT = 38.3%) and high coloration efficiency (CE = 47 cm2/C) were obtained for 6 at. % of Cr-doped Co3O4 film. The present work suggests that incorporation of Cr in Co3O4 will enhance its electrochromic performance. •Cr-doped Co3O4 films were deposited using nebulizer spray technique.•The chemical state of chromium in Co3O4 films is Cr3+ derived from XPS analysis.•The maximum coloration efficiency (47 cm2/C) is achieved for 6 at.% of Cr-doped Co3O4 film.•Spherical flower type morphology with pores enhanced the electrochromic performance.