A group of researchers led by Gert-Jan Wetzelaer from the Max Planck Institute for Polymer Research has come up with a groundbreaking approach to simplify the manufacturing of blue organic light-emitting diodes (OLEDs). These blue OLEDs are crucial components in devices like smartphones and televisions, and their efficient production has been a long-standing challenge.
In current OLED displays, each pixel comprises three micro-sized OLEDs, one for each primary color: red, green, and blue. For instance, a typical TV screen with around 2 million pixels actually consists of a staggering 6 million individual light-emitting diodes. Therefore, making these blue OLEDs more accessible and energy-efficient is essential to reduce manufacturing and electricity costs.
Traditionally, blue OLEDs have been hard to produce efficiently. Most modern OLEDs utilize a complex multilayer structure, sometimes involving up to seven layers, to achieve an efficiency of light emission between 20% and 30%.
However, the team led by Gert-Jan Wetzelaer has introduced a revolutionary OLED design. They’ve demonstrated that instead of the conventional seven-layer approach, a single active layer situated between two contacts is sufficient to create an efficient blue OLED. A critical aspect of their material is its ability to protect against defects like water and oxygen.
Wetzelaer notes, “Our material system opens the door to the potential future production of efficient blue OLEDs from a solution. This means moving away from multi-step processes and complex evaporation equipment, potentially allowing for OLEDs to be printed.”
Their single-layer OLED concept has achieved an internal quantum efficiency of 100%, implying that all the electrical energy supplied is converted into light. While some light is lost due to optical factors at interfaces, as is the case with any OLED, approximately 27% of the light is emitted outward—an impressive performance that rivals existing, complex commercial OLEDs.