QD-QLED is essentially a combination of technologies that uses quantum dots between the layers of LCD panels to replace the color filter for an LED backlight, thus emitting highly saturated primary colors.
Samsung QLED TV | Quantum Dot explained
A quantum dot is an artificially created nanocrystal with semiconductor properties that can improve the brightness and color performance of still images and video images on an LCD screen.
Quantum dots are emissive particles (a bit like phosphors on a plasma TV). When the particles are hit by photons from an external light source (in the case of an LCD TV application, a blue LED), each dot emits a color of a specific bandwidth, which is determined by its size. Larger dots emit light tilted toward red. As the dots get smaller, the dots emit light tilted toward green.
When quantum dots of certain sizes are grouped into a structure and combined with a blue LED light source, the quantum dots emit light across the full color bandwidth required for watching television.
