Yeah, the main problem with LEDs is that you only get max efficiency if you can find something with the right bandgap. Right now that means deep blue. 220 w/lm

Yeah, the main problem with LEDs is that you only get max efficiency if you can find something with the right bandgap. Right now that means deep blue. 220 w/lm is theoretical max for a smooth spectrum of white light. If you get to choose a spectrum you can get much higher using green centered at 555nm. If any "white" light advertises close or above 220 lm/watt the CRI suffers. It means they're using light that activates the human retina better but isn't actually a pure white. Lumens are calculated based on human eye response https://en.m.wikipedia.org/wiki/Luminosity_function https://en.m.wikipedia.org/wiki/Luminosity_function Looked at this way blue lights are pretty terrible. But if you look at mw of photons vs energy input deep blue LED's are close to 80% efficient.