The document discusses organic light emitting diodes (OLEDs). It describes the structure of an OLED, which consists of a cathode, emissive layer, conductive layer, anode and substrate. Electrons enter through the cathode and holes through the anode. When they combine in the emissive layer, light is emitted. OLEDs have advantages like lower power consumption, flexibility and thinness, but also disadvantages such as limited lifespan and sensitivity to damage. Potential applications of OLEDs include mobile phones, displays, medical devices and more.