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(PHosphorescent OLED) An OLED material that provides up to four times the efficiency of conventional fluorescent OLEDs. With its UniversalPHOLED brand of chemicals first commercially deployed in 2003, Universal Display Corporation (UDC), Trenton, NJ ( is the leader in phosphorescent OLED technology.

PHOLED is a small molecule, non-polymeric technology that consumes less power than LCDs. Combined with the intense colors of OLED, PHOLEDs are helping OLED become the dominant display technology of the 21st century. See OLED.

OLED Layers Using PHOLED
An OLED is a series of organic thin films sandwiched between two thin-film conductive electrodes, all deposited onto a substrate. When electricity is applied, charge carriers (holes and electrons) are injected from the anode and cathode into the PHOLED layer and recombine to form excitons, which cause photons to emit. (Image courtesy of Universal Display Corporation,


(Organic Light Emitting Diode) A display technology that offers rich colors, high contrast, deep blacks, wide viewing angle, low power and fast response time for sports and action scenes. The "O" in OLED comes from the use of "organic" carbon emitting layers rather than silicon or gallium as with LEDs (see diagram below).

OLED shares similarities with LED/LCD TVs and earlier plasma sets. Like LCD screens, white OLED (WOLED) passes light through color filters, while RGB OLED resembles plasma screens that intrinsically generate red, green and blue colors. Because OLEDs use light-emitting films, the screens are ultra-thin. See WOLED.

Extremely Versatile
OLEDs can be transparent, enabling them to function in heads-up displays and as window shades that react to sunlight. They are also used for lighting. OLED's color, speed, thinness, transparency and flexibility make it the display technology of the 21st century. See OLED lighting.

Passive and Active OLEDs
Passive matrix OLEDs appeared in cellphones and MP3 players in the 1990s, and active matrix OLEDs followed in 2003. Four years later, Sony introduced the first active matrix OLED TV (see image below). However, significant progress was made in the next five years, and LG and Samsung debuted 55" OLED TVs in 2012. See PHOLED, AMOLED, TOLED, OLED lighting and LED.

First OLED TV - Only 11 Inches
In 2007, Sony's XEL-1 captivated audiences with intense colors, but few were sold due to its small 11" screen and whopping USD $2499 price. To enhance the thinness of the screen, it was separated from the tuner circuits. (Image courtesy of Sony Corporation.)

From 11 to 77 Inches
A huge difference in seven years. At CES 2014, several large-screen OLED HDTVs were unveiled, such as this curved 77" 4K TV from LG. See 4K TV.

OLEDs Are Monolithic Devices
OLED screens consist of a series of carbon-based "organic" layers between electrical contacts (electrodes). Like LEDs, when electrons and holes combine in the organic layer, they emit photons. Unlike LCDs, which have separate layers, each OLED layer is deposited on the other, creating a monolithic unit. Commonly constructed on glass, OLEDs can also be fabricated on plastic and flexible films, such as the Flexible OLED (FOLED) from Universal Display Corporation.

OLED Cross Section (Not to Scale)
The cathode layer can be reflective (OLED) or transparent (TOLED). OLEDs are made using small-molecule organic LEDs (SM-OLEDs) or less-expensive, lower-voltage and longer-lasting large-molecule polymer LEDs (P-OLEDs or PLEDs). (Illustration courtesy of Universal Display Corporation,

A Smartphone in Your Pen?
Flexible OLED screens like this are expected. At CES 2018, LG demonstrated a 65" OLED TV screen that rolls up when not in use. (Image courtesy of Universal Display Corporation,

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