QLED? Yeah, most of us know by now that it stands for Quantum Dot LED, but what is that, really. Sure, quantum implies really small, and that would probably be a good thing, but what's the bottom line. At this point, it means a possibly more efficient display and possibly purer, more saturated primary colors with a narrower spectral distribution. Essentially, it works exactly like other LCD sets, but the filter is replaced with a film or tubes containing particles with a size in dozens of atoms that respond to high energy light by passing either green or red light. The backlight consists of blue LEDs (without the yellow dyes to make the light white like other sets). Blue light, with its shorter wavelength, is the higher energy end of the visible spectrum, so it makes sense as the backlight. By not having to make it white, and by not having to filter back to blue, efficiency is gained. So you get a gain in efficiency and possibly color gamut, but you still have the other drawbacks of LCD such as black level and viewing angle, compared to say, OLED.
So no, there is no sub-atomic particle emitting various light colors. At least not yet. There are hints at some form of emmissive Q-dot technology coming, but nothing yet. Because the "dots" are inorganic, if something is developed similar to OLED, it should have better longevity characteristics than organic components. The down side to the Q-dot technology is the cadmium or other toxic elements that are required to produce it.