All-in-one electrochromic transparency-tuning window with an integrated metal-mesh heating film

Abstract

Electrochromic (EC) smart windows with transparency-tuning capability can provide buildings with effective sun-shading and privacy to occupants at low energy consumption. The essential requirements to EC windows are fast response, dynamic tunability and low-cost. Recent development in all-in-one electrochromic devices (ECDs) which combines electrolyte, EC and ion storage functions in a single gel has the advantage of single layer structure and can be manufactured in large areas at low cost. However, the coloring voltage and time of all-in-one ECDs can be influenced by the viscosity of active gel. By raising the working temperature, the ECD may have faster response time and lower coloring voltage due to reduced gel viscosity. To enable high working temperature, a high conductivity and high transparency metal-mesh heating film was integrated to an EC window glass. The coloring performance of the EC window was investigated at different heating temperatures compared to its room temperature performance. It was found that working at 70 °C the coloring efficiency was doubled and the response speed of the device is five times faster than that at room temperature. The integrated metal-mesh heating film also brought added benefits such as defog and defrost for car windshield.