‘Mechanical Breathing’ in Smart Windows

Smart windows come in many different configurations, but the most popular ones are called electrochromic devices, because they change color when a voltage is applied. Scientists at Purdue University assessed the mechanical properties at the nanoscale of the thin-film electrochromic material used in these electrochromic devices and discovered that this material can expand up to 30% in volume. This “mechanical breathing” can cause the material to wrinkle and push up against the other layers of the substrate, causing the electrochromic device to stop functioning.