Multi-functional Electrochromic Devices: Integration Strategies Based on Multiple and Single Devices

Electrochromism is the phenomenon of reversible color/optical change of materials induced by redox reactions under an applied electric field. Since electrochromism was first introduced by Platt in 1961, electrochromic (EC) technology continues to develope due to its advantages of multiple colors energy saving and controllability, and was applied in many fields, for example, smart windows, displays, anti-dazzling rear view mirrors, etc. Recently, with the rapid development of optoelectronic and photoelectric technologies, highly integrated electronic devices attracted extensive interests, and the EC technology is developed towards functionalization and intellectualization. For example, self-powered EC devices (ECDs) were fabricated through integrating with the green energy technology, which further reduced the building energy consumption. Because of the visualization of the EC phenomena by naked eyes, the signal reading became more convenient for the sensors integrated with ECDs. In addition, because of similar device structure, electrochemical principles, active components with other functional devices, a lot of multifunctional EC technologies were explored based on single device, facilitating applications of ECDs in EC infrared control, EC energy storage, and EC actuation. In light of the recent emerging progress of EC technology, we reviewed multi-functional EC systems based on the integration of multiple devices and single device, respectively, including self-powered ECDs, EC sensors, infrared ECDs, and EC energy storage devices, etc. The integration modes, structure design and performance optimization were also summarized for different types of the multi-functional ECDs. At last, we introduced the challenges and potential pathway of multi-functional EC integration in the future.