Efficient electrochromic nickel oxide thin films by electrodeposition

• Published in: Journal of alloys and compounds Vol. 489; no. 2; pp. 667 - 673
• Main Authors: Sonavane, A.C., Inamdar, A.I., Shinde, P.S., Deshmukh, H.P., Patil, R.S., Patil, P.S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 21-01-2010; Elsevier
• Subjects: CA; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electrochemical properties (CV; Electrochemical quartz crystal microbalance (EQCM); Electrodeposition; Electrodeposition, electroplating; Electrooptical effects; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nickel oxide thin films; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Porous materials; granular materials; Scanning electron microscopy; Specific materials; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; XRD; Scanning electron microscopy; Optical properties; Electrochemical quartz crystal microbalance (EQCM); Nickel oxide thin films; Electrodeposition; Electrochemical properties (CV; XRD; CA; Cubic lattices; Porous materials; Polycrystals; Electrochromism; Thin films; Energy gap; Size effect; Absorption spectra; Optical absorption; Coloration; Band structure; Electronic properties; Electrochemical properties (CV CA); Fluorine additions; Layer thickness; Tin additions; Electrochemical properties; Morphology; Electrolytes; Nickel; Microstructure; Quartz microbalance
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2009.09.146

Nickel oxide (NiO) thin films were prepared by electrodeposition technique onto the fluorine doped tin oxide (FTO) coated glass substrates in one step deposition at 20, 30, 40 and 50
min deposition times respectively. The effect of film thickness (thereby microstructural changes) on their structural, morphological, optical and electrochromic properties was investigated. The mass change with potential and cyclic voltammogram was recorded in the range from +0.3 to −0.8
V versus Ag/AgCl. One step deposition of polycrystalline cubic phase NiO was confirmed from X-ray diffraction study. Optical absorption study revealed direct band gap energy of 3.2
eV. The optical transmittance of the film decreased with increase in film thickness. A uniform granular and porous morphology of the films deposited for 20
min was observed. The film becomes more compact and devoid of pores when deposition time was increased to 30
min. Thereafter severe cracks are observed. All the films exhibit anodic electrochromism in OH
− containing electrolyte (0.1
M KOH). The maximum coloration efficiency of 107
cm
2/C and electrochemical stability of up to 10
4 colour/bleach cycles were observed for the films deposited for 20
min (film thickness of 104
nm).