Organic Light-Emitting Diode




Organic Light-Emitting Diode (OLED) is a flat light emitting technology fabricated by placing a series of organic thin film layers between electrodes. The organic compounds are electrically conductive and are considered organic semiconductors. When an electrical current passes through the devices, the light can be emitted from the emissive layer. OLED applications such as displays, lightings have many advantages. OLED devices are very thin, which have the thickness of organic layer in range of about 100nm. Also, the close relationship of organic materials to plastics allows OLEDs to make it compatible with plastic substrates and flexible. Compared with other displays, OLEDs do not need backlights and color filters because OLED pixels emit light directly which can be possible to be better power efficiency, light weight, wide viewing angles, great brightness, fast refresh rate and better contrast. For the future, it is turned out that OLEDs are suitable for curved and rollabe displays, wearable devices, transparent displays embedded in windows and new designed lamps.


Overcome the limitation of OLED




Despite its many strengths, several hurdles remain before OLED applications can be deployed on a commercial scale. One of the problems for OLEDs is the lifetime of the organic materials. Degradation of the organic materials occurs by the accumulation of nonradiative recombination and luminescence quenching in the emissive zone as well as moisture or oxygen from the outside. Additionally, blue OLEDs still have quite low efficiency and lifetime in comparison with red or green, which makes it difficult to realize full color spectrum although considerable researchers have been invested in improving these problems. Therefore, we have tried to solve them by researching on various ways, optimizing the device structures and materials, cavity effect, surface plasmon subwavelength optics, comparison of different substrates such as stainless steel, and so on.