Thin solid SnO 2 and SnO 2 / Mo (10%, 2:1 and 1:1) films with an ion‐storage capacity of 20 to 30 mC/cm 2 and weakly expressed cathodic electrochromism were deposited using the dip‐coating technique. The films were deposited from peroxo sols prepared by reacting SnCl 2 ⋅ 2 H 2 O and a metallic molybdenum precursor with H 2 O 2 . Thermogravimetric, surface area [Brunauer, Emmett, and Teller (BET)], x‐ray diffraction, and IR spectroscopic measurements of films heat‐treated at 500°C (5 min) revealed a nanocrystalline (grain size ∼30 Å) cassiterite structure with a large surface area (∼60 to 70 m 2 /g). The electrochemical properties of the films were studied in a 1 M LiClO 4 /propylene carbonate electrolyte using cyclic voltammetry (CV) at different scanning rates (0.1 to 200 mV/s). Electrochromic properties, measured in situ with ultraviolet‐visible measurements, revealed that the coloring/bleaching changes accompanying insertion/extraction of Li + ion processes are 10 to 15% for SnO 2 / Mo (1:1) films but decrease to a few percent with decreasing Mo content. Low‐scan‐rate CV measurements confirmed the presence of two different redox processes: Sn 4 + / Sn 2 + and Mo 6 + / Mo 5 + . This was confirmed from the ex situ IR spectroelectrochemical measurements of films charged/discharged to different extents. IR spectra of films heat‐treated at 500°C in a vacuum also showed that SnO 2 / Mo (2:1) films contain Brønsted acidic protons. These films, because of their low coloration efficiency (2 to 10 cm 2 /C), are promising counterelectrodes for electrochromic devices with light reflection modulation.
No takes yet. Share an insight, caveat, or question.
Krašovec et al. (1997) studied this question.