OLED

OLED, or organic light-emitting diode, is a flat-panel display technology that uses organic compounds that emit light when an electric current passes through them. Unlike LCDs, OLEDs are self-emissive; each pixel can emit its own light, enabling true blacks and high contrast.

A typical OLED stack consists of a sequence of organic layers between two conductors: an anode and a cathode. When a voltage is applied, electrons and holes recombine in the emissive layer to produce photons. The device efficiency and color are determined by the materials and layer architecture. Displays may use passive-matrix (PMOLED) addressing for smaller panels or active-surface matrix (AMOLED) with thin-film transistors (TFTs) for high-resolution screens.

Variants include WOLED (white OLED) used in some television designs with color filters or color-by-white schemes, and flexible OLEDs on plastic substrates. OLEDs are widely used in smartphones, televisions, wearables, and automotive displays. Large-area OLEDs often require robust encapsulation to prevent moisture and oxygen ingress.

Advantages include high contrast, wide viewing angles, fast response, and thin, lightweight form factors. They can be made transparent or flexible. Drawbacks include shorter blue-emission lifetimes, potential image retention or burn-in for static content, and higher production costs. Lifespan and efficiency can vary with driving conditions and color.

The technology was developed in the late 1980s by Ching W. Tang and Steve Van Slyke at Eastman Kodak. Since then, OLEDs have been commercialized by multiple manufacturers and continue to be refined for efficiency, durability, and longer lifespans.