Researchers have developed a breakthrough tandem electrode structure that integrates both anodic ( NiO ) and cathodic ( W 18 O 49 ) electrochromic materials onto a single substrate. By inserting a conductive ITO interlayer, the team successfully overcame the common problem of material interference, significantly speeding up response times and enhancing coloration efficiency. This innovation allows smart windows to switch seamlessly between transparent, brown, and blue states, providing dynamic control over both visible light and heat-producing near-infrared radiation for more energy-efficient buildings.
Electrochromic materials, which change color in response to an electrical potential, are the backbone of next-generation "smart windows". However, many devices are limited to a single color or suffer from slow switching speeds when multiple materials are combined. In a study recently published, researchers have introduced a novel tandem-structured electrode that not only offers multi-color displays but also achieves superior spectral modulation across the visible and near-infrared ranges.
The research team, involving scientists from the Southern University of Science and Technology, tackled the challenge of "mutual interference" between different electrochromic materials. When different materials are layered together, they often block each other’s electron and ion pathways, leading to sluggish performance.
To solve this, the researchers designed a NiO/ITO/ W 18 O 49 (NIW) tandem architecture using a layer-by-layer assembly strategy. The structure features porous NiO nanosheets and an entangled network of W 18 O 49 nanowires. The critical innovation lies in the ITO interlayer inserted between them.
The team published their review in Nano Research on June 22, 2026
“In this study, we present a tandem-structured electrochromic electrode that integrates anodic and cathodic materials on a single substrate for multi-spectra modulation. These electrodes, designed for next-generation smart windows, are introduced with a focus on their multi-mode display, conductive interlayer design, manufacturing process, and performance features. Additionally, we delve into potential future developments for electrochromic devices, including improved energy efficiency, color diversity, and spatial modulation,” said Jin-Long Wang, senior author of the paper, assistant professor in the Department of Materials Science and Engineering and Guangming Advanced Research Institute at the Southern University of Science and Technology. Dr. Wang is also the State Key Laboratory of Quantum Functional Materials at the Southern University of Science and Technology.
Electrochromism refers to the reversible change in optical properties—such as transmittance or reflectance—of materials induced by electrochemical redox reactions. These reactions involve the insertion and extraction of ions and electrons under an applied potential. Inorganic electrochromic materials like oxygen-deficient tungsten oxide ( W 18 O 49 ) are critical for smart window technology due to their high stability and ability to modulate near-infrared light.
The research team outlines the progress made in a novel NiO / ITO / W 18 O 49 (NIW) tandem architecture. “By assembling porous anodic NiO nanosheets and cathodic W 18 O 49 nanowires with a conductive ITO interlayer on the same electrode, we have overcome the mutual interference typical of multi-component systems. This allows the electrode to switch reversibly between transparent, brown, and blue states,” Jin-Long Wang said.
Humans can benefit from the dual-band spectral regulation of these smart windows, which independently control visible light (400-800 nm) and near-infrared radiation (800-1600 nm). The team demonstrated four distinct modes: a “bright” mode at 0 V, a “warm” mode at 1.5 V for visible light modulation, and “cool” or “dark” modes at -1 V to -1.5 V for intense solar heat blocking. “This architecture decouples the responses of anodic and cathodic materials, enabling interference-free color expression and wavelength-selective modulation,” Jin-Long Wang said.
One of the challenges of electrochromic development is overcoming the sluggish kinetics and slow response times of conventional materials. To address this issue, the team incorporated a thin ITO interlayer that serves as a conductive bridge, lowering the effective work function and facilitating rapid electron transport. This led to a 14.46% and 53.4% reduction in the coloring and bleaching times of the W 18 O 49 layer, from 10.1/7.06 s to 8.64/3.29 s, while enhancing coloration efficiency to 71.15 cm 2 C - 1 .
The research team expects this tandem design to spur the development of high-performance smart windows that improve energy conservation in buildings. In practical tests, the device reduced the blackbody temperature in a model room by up to 21.2 °C compared to standard glass. “Tandem-structured electrochromic electrodes are expected to become more practical for modern green buildings and multi-color displays in the coming years. On the same surface, the window can interact with the environment in many different ways to optimize both comfort and energy savings.” said Jin-Long Wang.
Other contributors include Menghan Zhu, Sizhe Sheng, Xuefeng Huang, Chen Chen, Zongying Huang, Fuxing Zhao from department of materials science and engineering at Southern University of Science and Technology in Shenzhen, China; and Shuhong Yu from department of Chemistry at Southern University of Science and Technology and Institute of Biomimetic Materials & Chemistry at the University of Science and Technology of China in Anhui, China.
This work was supported by the National Natural Science Foundation of China (Grants 52373243, 22575112, 52503317, and 224B2504), Shenzhen Science and Technology Program (JCYJ20220530113200002, KQTD20221101093559017, and ZDSYS20220401161800001), Guangdong Provincial Key Laboratory of Sustainable Biomimetic Materials and Green Energy (2024B1212010003), Guangdong Innovative and Entrepreneurial Research Team Program (2023ZT10C027), High level of special funds (G03050K002), and the New Cornerstone Science Foundation.
DOI Link:
https://doi.org/10.26599/NR.2026.94908696
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 8,000 articles. In 2025 InCites Journal Citation Reports, its 2025 IF is 9.4 (8.3, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.
Nano Research
New Tandem Electrode Design Boosts Smart Window Performance for Multi-Spectral Control
22-Jun-2026