posted on 2020-05-18, 21:03authored byCamila
A. Saez Cabezas, Kristen Miller, Sungyeon Heo, Andrei Dolocan, Gabriel LeBlanc, Delia J. Milliron
Transition metal
oxide coatings, owing to their unique combination
of optoelectronic, electrochemical, and chemical properties, are at
the forefront of functional thin films across diverse technologies.
However, achieving uniform and conformal metal oxide thin films of
precise nanoscale thickness and optical quality is largely limited
to atomic layer deposition methods. Here, we report a direct, fast,
solution-based, ambient-condition electrochemical method to deposit
transparent thin films of amorphous niobium oxide and tantalum oxide
from polyoxometalate precursors dissolved in aqueous electrolytes.
The acid-catalyzed condensation of the polyoxometalates is driven
by the potentiostatic oxidation of water at the surface of the transparent
working electrode. Film thickness can be tuned at the nanoscale by
varying the applied potential. We deposited niobium oxide and tantalum
oxide conformally on mesoporous nanocrystal films to demonstrate the
abilities of this electrochemical method as an alternative approach
to fabricate optical quality composites. These composites exhibit
electrochromic and antiphotochromic performance comparable to that
of the equivalent composites fabricated by established conventional
methods such as atomic layer deposition.