ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Electrochromic properties and contrast ratio optimization of titanium oxide films synthesized in nitrate melts

Mikhail P. Kuz’min and Marina Yu. Kuz’mina

Irkutsk National Research Technical University, Irkutsk, Russian Federation

E-mail: mike12008@yandex.ru

Received: 14 April 2025  Accepted: 18 September 2025

Abstract:

Study investigates the electrochromic properties of titanium dioxide (TiO₂) films synthesized by anodic oxidation of titanium in alkali nitrate melts with potassium fluoride additives. The optimal synthesis parameters to achieve a high contrast ratio (K = 7–8) were established: potentiostatic mode, temperature of 625 ± 10 K, voltage of 20 ± 5 V, process duration of 5–12 min, and a KF concentration of 0.01–0.04 mol/kg in a NaNO₃–KNO₃ eutectic melt. A comprehensive characterization of the films was performed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM). The results confirm the formation of a nanocrystalline mixed-phase (anatase and rutile) TiO₂ film with a thickness of ~ 578 nm. EDX analysis revealed the incorporation of fluorine into the oxide matrix, which promotes the formation of oxygen vacancies and enhances ionic conductivity. The nanostructured morphology and optimal defect density are identified as key factors contributing to the superior electrochromic performance. The findings highlight the strong potential of the developed TiO₂ electrodes for application in electrochromic devices, such as smart windows and information displays.

Keywords: Transition metals; Oxidation; Electrochromism; Electrochromic materials; Memory effect

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04396-8

Chemical Papers 80 (1) 335–343 (2026)