Spatially resolved measurement of inhomogeneous electrocoloration/insertion in polycrystalline molybdenum oxide thin films via chronoabsorptometric imaging.

A new integrated electrochemical and transmission optical microscopy approach is presented which allows for elucidation of inhomogeneous ion/charge-transfer behavior in polycrystalline electrochromic/insertion materials. Spatially resolved Li+ diffusion coefficients and ionic conductivities are determined from the time-lapsed optical density imaging response monitored during electrochemical potential-step perturbation. Non-uniform coloration changes and dispersed insertion kinetics are observed and associated with domain specific reactivity of polymorphous materials comprising alpha-MoO3 and beta-MoO3.