This document discusses organic light-emitting diodes (OLEDs). It provides an introduction to OLEDs, describing them as solid state devices made of thin films of organic materials sandwiched between electrodes. The document then covers the history, components, operation, types (including passive matrix OLED, active matrix OLED, transparent OLED), advantages, disadvantages, and applications of OLEDs. Key advantages listed are brightness, flexibility, viewing angles, power efficiency, and light weight. The document concludes that OLEDs offer advantages over LEDs and LCDs in being thinner, lighter, and more flexible.