OLED – organic light emitting diode – displays are extremely thin, lightweight and energy-efficient. They deliver a perfect image from every viewing angle with extraordinary color brilliance and very high contrast. Due to the low energy consumption, small OLED displays are well suited for use in portable devices, like smartphones, digital frames, and digital cameras. OLED displays are also suitable for televisions, monitors, large-area video walls, and in automotive applications. Flexible or rollable displays are already realized.

In contrast to LCDs, OLED displays do not require backlighting, since each pixel generates light individually. As a consequence, the device structure of OLEDs are much simpler, as illustrated below.

OLEDs have a simple structure. They consist of organic semiconductor molecules deposited on a substrate of glass or flexible film between conducting electrodes. When a current flows between the electrodes, pairs of electrons and holes are formed, which generates excitons. They return from the excited state to the ground state by emitting light. The molecular structure of the semiconductors used determines the color of the emitted light. An OLED stack consists of different layers of OLED materials; each OLED material layer has its own characteristic function.

Nothing to stop flexible displays and lighting

OLEDs can be applied on rigid glass or on flexible substrates like plastic or metal foils. The advantage: OLEDs can turn virtually every surface into a display or light source. In the future, this will enable new kinds of applications beyond traditional displays and lighting.