Hybrid molybdenum-tungsten oxide as novel plasmonic electrochromic nanomaterial

Abstract

In this work we studied the synthesis, dispersion and wet deposition of molybdenum-tungsten hybrid oxide as novel plasmonic electrochromic materials. We successfully synthesized these hybrid materials using a one step solvothermal route. The recovered powders were characterized in terms of their morphology, crystallinity, optic properties, and behavior under annealing conditions. Then, the powders were dispersed in usual low toxic solvents to be used as "electrochromic inks" for the ensuing deposition. The stability of the dispersions was evaluated both qualitativelly and quantitatively, with and without addition of stabilizing agents. The best results were obtained using either a dispersing agent (PEG 140k in ethanol and PEI in water) or in the case of heavily loaded suspensions (150 mg/mL), taking advantage of the interparticle steric hindrace. 10 mg/mL dispersions with PEG in ethanol and 150 mg/mL surfactant-free dispersion in ethanol were used as active "inks" for spin coating and bar casting respectively. We managed to produce active films using both techniques, however, the superior quality of the deposited film using bar casting led to improved electrochromic properties