Just published this week, researchers at Hiroshima University have created a working quantum LED emitter from rice husks, deep red. Fascinating.
Will it ever see the light of day? Nichia? 
!https://www.hiroshima-u.ac.jp/system/files/183546/Additional%20multimedia1.jpg !
Hopefully its not some weird side effect of nuclear fallout.
Not quite “sustainable” as much as “can be done”.
Still, interesting way of getting what sounds like nano-Si/-SiO2.
Sustainable in the sense that it is not using toxic materials, heavy metals, etc. If this ever becomes anything, I’m nearly positive it will never be in a flashlight.
