Electrochemical Characteristics of Reconstructed WO₃ Electrodes by Embedding ITO Nanocrystals

ITO nanocrystal-embedded WO3 electrodes (ITO@WO3) have been successfully fabricated with a facile solution process, and the structure and electrochromic properties were studied by transmission electron microscope, scanning electron microscope, X-ray diffraction and electrochemical methods. The results show that moderate embedding of ITO nanocrystals (NCs) effectively improves the electrochromic performance that the optical modulation and coloration efficiency are increased from about 20.86% and 30.18 cm(2) C-1 to about 29.37% and 33.49 cm(2) C-1, respectively. Further analysis of the cyclic voltammetry and chronoamperometry indicate that the diffusion-controlled reactions associating with the electrochromic of the electrodes are enhanced with the increasing ITO NCs at the low content, while the excessive ITO NCs inhibit them. On the other hand, the capacitive contribution to the total insertion/extraction charges keep steady with various ITO NCs contents in the considering range of the present work, suggesting that ITO NCs affect little on the capacitive nature of the WO3 matrix. These results provide a better understanding of the electrochemical kinetics of the nanocrystal embedded electrodes and are helpful to design more efficient electrochromic devices.