Various Coating Methodologies of WO₃According to the Purpose for Electrochromic Devices

• Main Authors: Keon-Woo Kim, Yong Min Kim, Xinlin Li, Taehwa Ha, Se Hyun Kim, Hong Chul Moon, Seung Woo Lee
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Nanomaterials
• Subjects: electrochromic device; tungsten trioxide; printed electronics; slot-die; electrohydrodynamic jet printing
• Online Access: https://www.mdpi.com/2079-4991/10/5/821

Solution-processable electrochromic (EC) materials have been investigated widely for various applications, such as smart windows, reflective displays, and sensors. Among them, tungsten trioxide (WO₃) is an attractive material because it can form a film via a solution process and relative low temperature treatment, which is suitable for a range of substrates. This paper introduces the slot-die and electrostatic force-assisted dispensing (EFAD) printing for solution-processable methods of WO₃ film fabrication. The resulting films were compared with WO₃films prepared by spin coating. Both films exhibited a similar morphology and crystalline structure. Furthermore, three different processed WO₃ film-based electrochromic devices (ECDs) were prepared and exhibited similar device behaviors. In addition, large area (100 cm²) and patterned ECDs were fabricated using slot-die and EFAD printing. Consequently, slot-die and EFAD printing can be used to commercialize WO₃ based-ECDs applications, such as smart windows and reflective displays.