Quantitative Assessment of the Cycling Stability of Different Electrochromic Materials and Devices

Despite the long-standing history of electrochromism, there is a lack of universally accepted methods for quantitatively comparing cycling stability between different electrochromic materials or devices. By proposing a straightforward three-step procedure, we report a simple set of parameters that describe the cycling stability performance the most frequently used electrochromic materials, namely, conducting polymers, transition metal oxides, metallo-supramolecular polymers, and viologens. The main highlights of this procedure are an adequate definition of the testing conditions and the analytical description of the evolution of the performance of materials through continuous cycling. The resulting parameters allow us, not only to perform comparative studies among different materials and devices but also to identify tendencies, and therefore establish the corresponding balance, between the testing conditions and the cycling stability and/or optical performance obtained. This method constitutes a powerful decision-making tool for the academic and industry-related electrochromic community.