Electrochromic perspective of indium-free bi-functional and porous stacked WO₃/Ag/WO₃ structures towards efficient and cost-effective ECDs

Indium-free, bi-functional & porous WO₃/Ag/WO₃ (WAW) film stack endeavour towards execution of dual performance as transparent electrodes and electrochromic materials. This work presents a comparative study of planar and GLAD (Glancing angle deposition) WAW films towards Electrochromic Device (ECD) application. For this purpose, innoxious, economical porous WAW film has been prepared at a GLAD angle 65° and its performance was compared with a planar WAW film of same thickness. WAW film prepared at 65° proclaimed not only high optical transmittance but also fascinating electrochromic performance with high optical modulation of 67% at 600 nm, elevated coloration efficiency of 46.08 cm²/C, diffusion coefficient of 6.95 × 10⁻⁶ cm²/s and low optical density of 2.12. These modest performance of GLAD angled WAW film can be attributed to the highly porous texture inculcated due to optimized GLAD geometry. Thus, it is concluded that electrochromic performance of WAW film can be effectively enhanced with GLAD geometry owing to optimized porous texture resulting from agglomeration of nanocolumnar structure. Moreover, this GLAD angled WAW film is scopious for making ECDs Indium-free because it substitutes ITO and provides optimized porous texture for better electrochromism with a tendency to address cost-effectiveness of an ECD.