Quote:
Originally Posted by jbjb
There *are* white LEDs, as I've explained above. Still experimental technology, but they exist in the lab and look promising for commercial development.
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You can't buy them, and they can't be decent colour rendition without a layer on top of the LED.
LEDs work by a band gap* which sets the narrow band colour. If such a lab device really gives broad spectrum light then it's not really an LED.
[* That is defined by the materials, though temperature and current do shift the narrow band emission]
So, no there are currently no actual LEDs that are natively white, and if what ever that is ever leaves the lab to production it will turn out to be not actually an LED.
OLED for example are not "real" LEDs. They are actually diode-like electroluminescent printed dots with phosphors to get the red, green and blue colours. There are some very expensive displays that use real LEDs. Nothing domestic. QLED panels are actually LCD panels with a blue LED backlight and "quantum" dots for the red and green parts of the LCD. These are more efficient than phosphors with also a faster response time. Phosphors are slow.