A quantum dot display is a display device that uses quantum dots (QD), semiconductor nanocrystals which can produce pure monochromatic red, green, and blue light.
Photo-emissive quantum dot particles are used in a QD layer which converts the backlight to emit pure basic colors which improve display brightness and color gamut by reducing light losses and color crosstalk in RGB color filters. This technology is used in LED-backlit LCDs, though it is applicable to other display technologies that use color filters, such as white or blue/UV OLED or MicroLED. LED-backlit LCDs are the main application of quantum dots.
Electro-emissive or electroluminescent quantum dot displays are an experimental type of display based on quantum-dot light-emitting diodes (QD-LED; also EL-QLED, ELQD, QDEL). These displays are similar to active-matrix organic light-emitting diode (AMOLED) and MicroLED displays, in that light would be produced directly in each pixel by applying electric current to inorganic nano-particles. QD-LED displays could support large, flexible displays and would not degrade as readily as OLEDs, making them good candidates for flat-panel TV screens, digital cameras, mobile phones, and handheld game consoles.
As of 2019, all commercial products, such as LCD TVs using quantum dots and branded as QLED, use photo-emissive particles. Electro-emissive QD-LED TVs exist in laboratories only, although Samsung is working to release Electro-emissive QDLED displays "in the near future", while others doubt that such QDLED displays will ever become mainstream.
Emissive quantum dot displays can achieve the same contrast as OLED and MicroLED displays with "perfect" black levels in the off state. Quantum Dot displays are capable of displaying wider color gamuts than OLEDs with some devices approaching full coverage of the BT.2020 color gamut.