Electrochemical and optical properties of sputter deposited Ir–Ta and Ir oxide thin films

Addition of tantalum oxide has been investigated in order to improve the electrochromic properties of iridium oxide. Films of iridium–tantalum oxide and iridium oxide have been prepared and studied with regard to their optical and electrochemical properties. It can be seen that the addition of tantalum decreases the optical absorption coefficient and increases the ion diffusion coefficient. The change of properties is thought to be a result of the dilution of colouring iridium oxide with the better ion conducting tantalum oxide.