Flexible ECL prototypes reach 1,552 candelas per square meter

A flexible panel glows under indoor lighting, where dimness has long kept electrochemiluminescent displays from leaving the laboratory. A team led by Assistant Professor Tan Yu Jun at the National University of Singapore has now reported ECL prototypes reaching 1,552 candelas per square meter—about three to four times the brightness of a typical indoor smartphone screen.

ECL, short for electrochemiluminescence, makes light through electrically triggered chemical reactions in a liquid layer between two electrodes. The format is thin and flexible, but conventional versions have been too faint and unstable for practical displays. The researchers also report a steady, continuous glow that can run on a small battery.

The change began inside the liquid. The team replaced the conventional ionic liquid, a salt that remains liquid at room temperature, with one containing a smaller negative ion. That ion accelerated electron exchange at the electrode and improved chemical stability, while the positive ion dissolved more of the light-emitting dye. The device then paired a textured electrode for stronger reactions with a smooth electrode optimized for transparency, adding a thin silver mirror to reflect escaping light forward.

The durability gap was visible in testing. After 10 cycles of repeated switching on and off, the new devices maintained brightness up to 82 times higher than the conventional version. Under continuous operation, they sustained emission for two hours, compared with 29 minutes for the older design. The results were published in Science Advances by researchers from NUS, the Institute of Materials Research and Engineering and the Institute of High Performance Computing.

Concretely, the technology could put visual feedback directly on a skin-worn glucose monitor, without a separate screen. The team also demonstrated a seven-segment panel displaying the numbers 1 to 9, and a flexible solid-state device that continued glowing while fully submerged in water. Those prototypes point to simple displays for environmental sensors, smart packaging, machine or soft-robot surfaces, and underwater signaling—but they remain demonstrations, not deployed products.