OLED uses actually light as the source of the image. Unlike ALL LCD technologies, when you use a OLED TV, you are looking directly at a light source. When the screen is red, you are staring at a RED organic LED light.
With QLED you are just looking at another LCD technology. You are looking through different color filters on the LCD screen that turn white light into different colors. So, if you have that same red image that you looked at with OLED, instead of seeing a red light directly, you are looking at a white light which has passed through a red filter to make it appear red. But, you aren't looking at the light source itself.
There are entire articles about what LCD is and what QLED is as it applies to LCD. Likewise, what OLED is.
QLED is a real improvement to LCD technology, but it is still LCD technology.
OLED is a completely different technology and has nothing to do with LCD or QLED.