The anodized crystalline WO3 nanoporous network with enhanced electrochromic properties.
We demonstrate that a three dimensional (3D) crystalline tungsten trioxide (WO(3)) nanoporous network, directly grown on a transparent conductive oxide (TCO) substrate, is a suitable working electrode material for high performance electrochromic devices. This nanostructure, with achievable thicknesses of up to 2 μm, is prepared at room temperature by the electrochemical anodization of a RF-sputtered tungsten film deposited on a fluoride doped tin oxide (FTO) conductive glass, under low applied anodic voltages and mild chemical dissolution conditions. For the crystalline nanoporous network with thicknesses ranging from 0.6 to 1 μm, impressive coloration efficiencies of up to 141.5 cm(2) C(-1) are achieved by applying a low coloration voltage of -0.25 V. It is also observed that there is no significant degradation of the electrochromic properties of the porous film after 2000 continuous coloration-bleaching cycles. The remarkable electrochromic characteristics of this crystalline and nanoporous WO(3) are mainly ascribed to the combination of a large surface area, facilitating increased intercalation of protons, as well as excellent continuous and directional paths for charge transfer and proton migration in the highly crystalline material.
School of Electrical and Computer Engineering, RMIT University, Melbourne, VIC, Australia. jianzhen.ou@rmit.edu.au
Jian Zhen
JZ
Ou
Sivacarendran
S
Balendhran
Matthew R
MR
Field
Dougal G
DG
McCulloch
Ahmad Sabirin
AS
Zoolfakar
Rozina A
RA
Rani
Serge
S
Zhuiykov
Anthony P
AP
O'Mullane
Kourosh
K
Kalantar-Zadeh