Electrochromic devices (ECDs) have been regarded as promising candidates for energy-saving smart windows, next-generation displays and wearable electronics due to their significant benefits of simple and adjustable structures, low power consumption, flexible and stretchable features, and eye-friendly modes for displays. However, there are many existing issues waiting to be solved such as durability, reversibility and inadequate switching performances. These insurmountable technical bottlenecks significantly slow down the commercialization of next-generation ECDs. Nanomaterials with superior active reaction surface area have played indispensable roles in optimizing heterogeneous electron transfer and homogeneous ion transfer for ECDs and other optoelectronic devices. In recent years, with the joint efforts of various outstanding research teams, new kinds and methods for nanomaterials to fabricate ECDs with excellent performances have been rapidly developing. This review highlights the latest exciting results regarding the design and application of new and unique nanomaterials for each layer of ECDs. Meanwhile, the structures, mechanisms, features and preparation of the reported nanomaterials to improve the electrochromic properties have been discussed in detail. In addition, the remaining challenges and corresponding strategies of this field are also proposed. Hopefully, this review can inspire more and more researchers to enrich the nanomaterials for ECDs and other related fields to overcome faced technical barriers by innovative means and promote industrialization of ECDs and other optoelectronic technologies.

Advances in nanomaterials for electrochromic devices

With the rapid development of optoelectronic fields, electrochromic (EC) materials and devices have received remarkable attention and have shown attractive potential for use in emerging wearable and portable electronics, electronic papers/billboards, see-through displays, and other new-generation displays, due to the advantages of low power consumption, easy viewing, flexibility, stretchability, etc. Despite continuous progress in related fields, determining how to make electrochromics truly meet the requirements of mature displays (e.g., ideal overall performance) has been a long-term problem. Therefore, the commercialization of relevant high-quality products is still in its infancy. In this review, we will focus on the progress in emerging EC materials and devices for potential displays, including two mainstream EC display prototypes (segmented displays and pixel displays) and their commercial applications. Among these topics, the related materials/devices, EC performance, construction approaches, and processing techniques are comprehensively disscussed and reviewed. We also outline the current barriers with possible solutions and discuss the future of this field.

Emerging Electrochromic Materials and Devices for Future Displays

ConspectusStimuli-responsive materials have a great potential in various novel photoelectric devices, such as self-adaptive adjustment devices, intelligent detection, molecular computers with infor...

Stimuli-Induced Reversible Proton Transfer for Stimuli-Responsive Materials and Devices.

Dual‐band electrochromism is a phenomenon where materials can independently regulate the transmittance of visible (VIS) and near‐infrared (NIR) light. Owing to their bistability, low energy consumption, and independent control over VIS and NIR regions, dual‐band electrochromic (EC) devices have been of great significance to fully harnessing VIS and NIR light and building an energy‐saving society. The past several years have witnessed the efforts put in developing novel EC materials to improve their dual‐band optical performance through altering their composition, structural, and physicochemical features, which determine the optical behavior of dual‐band EC devices. In this review, the concept, significance, working principle, and key influence factors of dual‐band electrochromism are briefly introduced. Next, the up‐to‐date progress of dual‐band EC materials including inorganic, organic, and composites materials are summarized, with a focus on material design, device fabrication, and performance optimization. Finally, the challenges and perspectives of dual‐band EC materials and devices are also presented.

Recent Advances on Dual‐Band Electrochromic Materials and Devices

Highly Stable Ag–Au Core–Shell Nanowire Network for ITO-Free Flexible Organic Electrochromic Device

Due to the high energy efficiency and a wide range of potential applications in daily life, bistable electrochromic devices (BECDs) have gained extensive attention in recent years. However, poor bistability and slow response rate are the main barriers, which restrict the development of BECDs. Herein, a transparent multidimensional electrode with indium tin oxide (ITO) nanofibers and gold nanoparticles was fabricated to improve both the bistability and responsiveness of devices. Its criss-crossed ITO nanofibers with high length-to-diameter ratios to reduce the distance of heterogeneous electron transfer and its gold nanoparticles to form a stable Au-S bond to avoid self-erasing of electrochromic materials have been demonstrated and discussed systematically. This device based on the transparent multidimensional working electrode had a shorter response time (1/5) and a longer bistability (12/1) compared with the prototype devices based on common fluorine-doped tin oxide electrodes. Besides, this device had a promising electrochromic performance with a high coloration efficiency of 448.27 cm2/C and a switching stability with no significant attenuation after 1200 cycles.

A Transparent Multidimensional Electrode with Indium Tin Oxide Nanofibers and Gold Nanoparticles for Bistable Electrochromic Devices.

A new and simple strategy towards electric-field-driven multiple chirality switching device has been designed and fabricated by combining a newly synthesized base-responsive chiroptical polymer switch (R-FLMA) and p-benzoquinone (p-BQ) via proton-coupled electron transfer (PCET) mechanism. Clear and stable triple chirality states (silence, positive, negative) of this device in visible band can be regulated reversibly (>1000 cycles) by adjusting voltage programs. Furthermore, such chiral switching phenomena are also accompanied by apparent changes of color and fluorescence. More importantly, the potential application of this device for a spatial light modulator has also been demonstrated.

Yiru Cai

Papers

Advances in nanomaterials for electrochromic devices

A Transparent Multidimensional Electrode with Indium Tin Oxide Nanofibers and Gold Nanoparticles for Bistable Electrochromic Devices.

A Multiple Chirality Switching Device for Spatial Light Modulators.