To quantitatively
characterize the optical coupling between ZnO
(a high refractive index but nonabsorptive material) and an electrochromic
material (either tungsten oxide (WO3) or poly(3,4-ethylenedioxythiophene)
(PEDOT)), electrodiffractive and electrochromic properties were investigated
from a novel two-component composite nanostructured electrodeposited
grating that incorporated both ZnO and either WO3 or PEDOT.
The sequential electrodeposition of these two materials through a
photopatterned photoresist layer onto a fluorine-doped tin oxide (FTO)-coated
glass substrate created a grating structure that exhibited optical
diffraction that could be modulated electrochemically. SEM images
of the electrochromic gratings revealed that the ZnO electrodeposition
created a high surface area nanostructured thin film. The nanostructured
ZnO is nonabsorbing, but its high refractive index and large surface
area redirect light into the electrochromic grating and create a 4-fold
enhancement in the grating’s electrodiffractive response.