High-Coloration Efficiency and Low-Power Consumption Electrochromic Film based on Multifunctional Conducting Polymer for Large Scale Smart Windows

Electrochromic devices (ECDs) exhibit significant potential as emerging electronics for applications associated with smart windows. They can dynamically control solar radiation consumption in buildings and vehicles to enhance efficiency. However, because smart windows are not optimized for high performance, and most are manufactured based on glass form, the large-area manufacturing process is complex and hinders its applicability to electrochromic (EC) devices. In this study, an ECD was fabricated on a PET film by a solution process using a multifunctional conducting polymer synthesized by oxidation polymerization. The polymer layer used was PEDOT:PSS and PANI:PSS, which alone can serve as an electrode and an EC layer, without the need for other electrode materials (ITO, FTO, etc.). The ECD showed excellent optical characteristics and cycle stability owing to the balanced surface charge capacity (insertion/exertion). An excellent coloration efficiency value (1872.8 cm2 C–1 at 600 nm) was obtained with low-power consumption (102 μW cm–2 (coloration) and 11 μW cm–2 (bleaching)). The characteristics of these materials and devices have significant applicability as large-area smart windows. When fabricated using the roll-to-roll method, a large-area smart window of 500 × 500 mm2 was produced. The heat-shielding characteristics (86.2%) were also excellent. Very good energy-savings were achieved and an all-organic smart window with excellent characteristics was verified. The capability of solution and low temperature processing for ECDs has the ability to significantly influence the industrialization of large-area smart windows.