Recent Advances in Electrochromic Devices: From Multicolor to Flexible Applications

With increasing demand for energy saving and environmental sustainability, electrochromic devices (ECDs) are considered as emerging display devices with low energy consumption. While various reflective-type displays produce images with low energy, achieving full color displays often involves much device complexity and nonflexibility. Multicolor ECDs aim to realize full color reflective-type displays, surpassing the current monochromic type or limited coloration capabilities in a 1D color space. Enhancing device flexibility is also highly desirable for use of ECDs in wearable and flexible electronics for health monitoring and advanced textiles with easy visualization. In this review, recent advances in multicolor and flexible ECDs are examined. Several primary strategies to achieve multicolor ECD are described, including material modifications, color overlay, and dye-mediated colorations. In addition, recent developments in flexible ECDs are explored, emphasizing novel materials and fabrication processes that improve mechanical durability and reliability under deformation. It is expected that this review will provide a comprehensive understanding of multicolor and flexible ECDs for applications in smart windows, displays, and wearable electronics. The review comprehensively introduces recent progress in multicolor and flexible electrochromic devices with discussion on materials, structures, fabrications, and potential applications of them in displays and wearable electronics.image (c) 2024 WILEY-VCH GmbH