Invention Could Cut Costs And Chemicals In Next-Generation Lighting

Researchers at the University of Turku in Finland have developed a new kind of colour-tunable white OLED that produces light from a single organic layer — a design that could dramatically simplify manufacturing, reduce costs, and eliminate the need for scarce materials such as indium tin oxide (ITO).

White OLEDs are used in high-end displays and architectural lighting, but conventional versions rely on complex stacks of organic materials mixed with red, green and blue dopants containing heavy metals. These components require precise tuning, generate chemical waste, and raise sustainability concerns.

The Turku team’s approach replaces this complexity with optical engineering. Their device uses a single sky-blue, metal-free emitter molecule (DMAC-DPS) placed between two standard aluminium electrodes, which also serve as mirrors. This creates a microcavity — a tiny optical chamber that reflects and reshapes light, effectively acting as a “hall of mirrors.”

By adjusting the thickness of the emissive layer, the researchers can fine-tune the cavity’s resonance to alter the colour output. At the same time, surface plasmon polaritons — ripples of electromagnetic energy that travel along the metal surfaces — interact with the light waves to broaden the emission spectrum. Together, these effects enable the OLED to produce tunable white light ranging from warm (around 3,790 K) to cool (around 5,050 K) tones, without the need for multiple emitters or dopants.

“Our breakthrough is about getting more with less,” said Manish Kumar, the study’s lead author. “You don’t need complicated RGB colour mixing to get white light. By letting the cavity and surface plasmons do the work, we can turn a single blue emitter into a tunable white OLED — without ITO and with a much simpler structure using materials already familiar to manufacturers.”

The simplified design could significantly reduce the environmental and economic footprint of OLED production. It avoids rare materials, requires fewer processing steps, and can be integrated into existing vacuum-deposition lines. Because it is top-emitting, the device is also compatible with reflective and flexible surfaces — making it suitable for thin backlights, architectural luminaires, and smart-building applications.

“This work shows how clever optical design can replace chemical complexity,” said Professor Konstantinos Daskalakis, who led the research group. “By removing ITO and heavy-metal dopants, we’re pointing towards lighting that is more sustainable, easier to manufacture, and better for both the environment and global supply chains.”

The team now plans to test the device’s brightness, efficiency, and long-term stability as it moves toward real-world lighting applications. The study appears in Advanced Optical Materials.