The advance addresses a problem that has held back flexible displays for years. Organic light-emitting diodes can produce vivid images, but they require complex stacks of thin functional layers that are difficult to bend repeatedly without damage. Light-emitting capacitors have a simpler structure, yet often need hundreds or thousands of volts, making them impractical for wearable electronics. Electrochemiluminescent, or ECL, devices appear to offer a more natural alternative: they are thin, flexible and potentially energy efficient. Their weakness has been their low brightness and poor operating lifetime, which made them more suitable for laboratory demonstrations than real-world displays.

ECL devices produce light through electrochemical reactions in a liquid layer placed between two electrodes. When an alternating electrical voltage is applied, a light-emitting molecule in the electrolyte repeatedly gains and loses electrons. These oxidation and reduction reactions create excited molecular states, and when the molecules return to their lower-energy state, they release photons. The process resembles bioluminescence in principle, although electricity rather than a biological reaction drives the emission. In earlier devices, however, slow ion movement, inefficient charge transfer and chemical degradation at the electrode interface consumed much of the available energy before it could become visible light.

The Singapore-led team, headed by Assistant Professor Tan Yu Jun of NUS’s Department of Mechanical Engineering, focused first on the liquid electrolyte. Conventional ECL systems commonly use an ionic liquid, a salt that remains liquid at room temperature. Although ionic liquids are attractive because they do not evaporate easily and can support electrochemical reactions, their relatively large ions can move sluggishly through the device. The researchers replaced the conventional electrolyte with one containing a smaller, more mobile negative ion. This change accelerated interfacial electron exchange and reduced chemical instability near the electrode, allowing the light-producing reactions to proceed more efficiently.

The researchers also found that the two ions in the liquid play different roles in determining performance. The smaller negative ion helps charges move rapidly and suppresses unwanted chemical reactions, while the positive ion improves the solubility of the light-emitting dye. A higher concentration of dissolved emitter gives the device more molecular material with which to generate photons. Together, these effects increase both the speed of the electrochemical reactions and the amount of light-emitting “fuel” available inside the liquid layer. The result is not simply a brighter flash, but a more productive and stable reaction cycle.

Device architecture provided a second major improvement. Instead of placing two identical transparent electrodes on opposite sides of the active layer, the team paired electrodes with different functions. One electrode was textured to increase the effective area and promote electrochemical reactions, while the other was kept smooth to preserve optical transparency. A thin silver mirror behind the rear electrode redirected light that would otherwise escape backward, sending more of the generated emission toward the viewer. This asymmetric arrangement allowed the researchers to combine efficient charge transfer with improved light extraction without adding the elaborate multilayer structure associated with many conventional displays.

The redesigned devices also showed a substantial improvement in durability. During repeated on-and-off cycling, the new ECL system retained brightness up to 82 times higher than the conventional design after 10 cycles. Under continuous operation, it emitted light for two hours, compared with approximately 29 minutes for the older device. The researchers say the system can produce a steady glow rather than the brief flicker seen in earlier ECL experiments and can operate using a small battery. That combination of continuous emission, low operating power and mechanical flexibility is particularly important for displays intended to sit on skin, clothing, packaging or soft machines.

To demonstrate possible applications, the team built several working prototypes. One was a flexible skin patch that used red and blue light to indicate different readings from a sweat-glucose sensor. Such a system could eventually provide an immediate visual warning when a measured physiological signal moves outside a desired range, without requiring a separate phone or rigid screen. The prototype does not itself replace a medical diagnostic system, but it illustrates how sensing and visual feedback could be integrated into a single lightweight platform that conforms to the body.

The researchers also created a seven-segment display capable of showing the numbers one through nine and changing them rapidly over repeated cycles. This type of simple numerical interface could be useful in smart packaging, environmental sensors, machine surfaces and soft robots, where conventional rigid electronics may be difficult to integrate. A third prototype continued glowing while fully submerged in water, demonstrating a level of water resistance that could support underwater signalling and monitoring. Because ECL layers can be made thin, soft and transparent, future versions could become visual skins that communicate touch, movement or damage across the bodies of flexible machines.

The work, published in Science Advances on 20 May 2026, marks a significant step toward turning ECL from a chemically interesting light-emitting phenomenon into a practical display technology. The researchers acknowledge that colour performance remains uneven: red emission is currently the strongest, while blue and green light require further improvement in brightness and stability. Their next goals include developing new light-emitting molecules and electrolytes, refining electrode structures, and creating stretchable and self-healing devices that can continue functioning after deformation or minor damage. If those challenges are solved, flexible ECL displays could provide low-power visual communication directly on skin, wearable devices, underwater equipment and soft robotic surfaces.

Subject of Research: Electrochemiluminescent displays and flexible light-emitting devices

Article Title: Ionic liquid–regulated interfacial charge transport and asymmetric device architecture for high-performance electrochemiluminescence

News Publication Date: 20 May 2026

Web References: NUS College of Design and Engineering; Science Advances article

References: DOI: 10.1126/sciadv.aed9796

Image Credits: College of Design and Engineering, NUS

Keywords

Electrochemiluminescence, flexible displays, wearable electronics, ionic liquids, light-emitting devices, soft robotics, underwater displays, glucose sensing, electrochemistry, NUS CDE

Traditional electronic displays commonly convert electrical energy into heat when changing colors, leading to increased surface temperatures and greater energy consumption. This is especially problematic in applications exposed to sunlight or worn on the skin, where overheating can reduce comfort and performance. The new system counters this by leveraging a multilayered electrode architecture paired with a unique electrolyte solution containing silver ions. This configuration allows for controlled silver deposition that selectively absorbs light only in desired wavelengths, drastically minimizing heat absorption while maintaining vivid coloration.

The core innovation lies in the device’s ability to switch between reflective white and color states through electrochemical modulation. When the display is in its white state, a top reflective layer efficiently scatters sunlight, enhancing passive cooling by reflecting a broad spectrum of solar radiation. Upon application of voltage, silver ions in the electrolyte solution are electrochemically reduced and plated onto the bottom electrode, creating a colored state with precise spectral control. Unlike previous technologies where color change led to significant light absorption and consequent heat generation, this method only absorbs light within targeted narrow bands, thus avoiding excess warming.

Experimental evaluations revealed remarkable thermal performance. The prototype reduced substrate temperatures by 3 to 5 degrees Celsius compared to ambient conditions while exhibiting dynamic color changes—a feat unattainable with traditional passive cooling coatings that lack color modulation capabilities. Furthermore, in intense summer environments, this display achieved cooling improvements of up to 13 degrees Celsius over comparable devices, all while maintaining bright and attractive colors like magenta using significantly less electrical power. The synergy between electrochemical color switching and radiative cooling mechanisms offers unprecedented efficiency for display technologies.

Versatility was demonstrated by the researchers through the development of pixelated electrodes featuring individual electrolyte wells, enabling independent color control of discrete pixels. This architecture allowed the formation of crisp, legible letters visible under various lighting conditions including direct sunlight. Importantly, these electrochromic pixels operate reversibly with controlled silver cycling, ensuring durability and long-term stability essential for commercial deployment. The ability to customize and program colors on flexible substrates opens vast possibilities for interactive signage and adaptive lighting systems in real-world scenarios.

A key aspect of this technology is its mechanical flexibility. The researchers successfully integrated the display onto pliable plastic backings, which could be wrapped comfortably over a human forearm without compromising electrical or optical functionality. This flexibility showcases the device’s potential for wearable applications, where cooling performance directly translates to enhanced user comfort. Wearable devices might soon incorporate similar cooling displays to mitigate skin heat buildup during prolonged use, signaling a major step forward in personalized, thermally managed electronics.

From an environmental perspective, this electrochemically driven cooling display holds significant promise for reducing energy consumption and greenhouse gas emissions. Passive cooling materials have historically been restricted to white or metallic finishes with limited functional adaptability. By integrating color-tunable capabilities that simultaneously provide efficient solar heat rejection, this technology could dramatically lower the cooling loads of buildings employing large-scale digital billboards or smart windows. In effect, it bridges the gap between aesthetic versatility and environmental responsibility.

The underlying physics and materials science principles highlight the sophistication of this new approach. The multilayer electrode design optimizes both optical reflectance and electrochemical deposition dynamics, while the silver-containing electrolyte supports rapid, uniform plating and stripping cycles. Indium tin oxide (ITO) glass serves as a robust transparent electrode, facilitating electron transport without hindering light transmission. These careful material selections combine to create an electrochromic system that balances efficient color change kinetics with thermal management, setting a new benchmark for display engineering.

Looking ahead, integration into smart building facades and vehicle exteriors could transform urban environments into energy-saving ecosystems. Buildings embedded with these dynamic displays could actively reduce interior temperatures by reflecting sunlight in color-customizable patterns, reducing reliance on air conditioning and lowering operational costs. Vehicles equipped with similar systems could maintain cabin comfort passively while offering customizable exterior aesthetics, enhancing both efficiency and user experience.

Moreover, the scalability and manufacturability of this technology will be crucial for widespread adoption. The researchers note that the fabrication process relies on established electrochemical deposition methods and commercially available materials, suggesting that transition from laboratory prototypes to mass production may be feasible without prohibitive costs. Coupled with the anticipated durability from reversible silver cycling, these displays are well-positioned for commercial viability in markets demanding innovative, energy-conscious solutions.

In conclusion, this development marks a significant advancement in the field of electrochromic displays by addressing the critical problem of heat generation during color transitions. The fusion of dynamic color modulation with passive daytime radiative cooling offers an elegant solution to enhance energy efficiency, user comfort, and aesthetic versatility simultaneously. As climate change continues to drive demand for sustainable cooling technologies, this approach introduces a promising pathway for the next generation of smart, flexible, and environmentally responsible electronic signage and wearables.

Subject of Research: Dynamic flexible electrochromic displays with integrated passive daytime radiative cooling

Article Title: “Daytime Radiative Cooling with Electrochemically Driven Dynamic Colors”

News Publication Date: 12-Nov-2025

Web References: http://dx.doi.org/10.1021/acsenergylett.5c02196

References: Adapted from ACS Energy Letters 2025, DOI: 10.1021/acsenergylett.5c02196

Image Credits: Adapted from ACS Energy Letters 2025, DOI: 10.1021/acsenergylett.5c02196

Keywords

Chemistry, Sustainability