Editing Light-emitting diode (section)

=== Key challenges ===
LEDs require optimized efficiency to hinge on ongoing improvements such as phosphor materials and [[quantum dot]]s.<ref name=":0">{{Cite web|url=https://www.energy.gov/eere/ssl/led-rd-challenges|title=LED R&D Challenges|website=Energy.gov|access-date=2019-03-13}}</ref>

The process of down-conversion (the method by which materials convert more-energetic photons to different, less energetic colors) also needs improvement. For example, the red phosphors that are used today are thermally sensitive and need to be improved in that aspect so that they do not color shift and experience efficiency drop-off with temperature. Red phosphors could also benefit from a narrower spectral width to emit more lumens and becoming more efficient at converting photons.<ref>{{Cite web|url=https://www.energy.gov/eere/ssl/downloads/july-2015-postings|title=JULY 2015 POSTINGS|website=Energy.gov|access-date=2019-03-13}}</ref>

In addition, work remains to be done in the realms of current efficiency droop, color shift, system reliability, light distribution, dimming, thermal management, and power supply performance.<ref name=":0" />

Early suspicions were that the LED droop was caused by elevated temperatures. Scientists showed that temperature was not the root cause of efficiency droop.<ref>[http://www.digikey.com/us/en/techzone/lighting/resources/articles/identifying-the-causes-of-led-efficiency-droop.html Identifying the Causes of LED Efficiency Droop] {{webarchive|url=https://web.archive.org/web/20131213073051/http://www.digikey.com/us/en/techzone/lighting/resources/articles/identifying-the-causes-of-led-efficiency-droop.html |date=13 December 2013}}, By Steven Keeping, Digi-Key Corporation Tech Zone</ref> The mechanism causing efficiency droop was identified in 2007 as [[Carrier generation and recombination#Auger recombination|Auger recombination]], which was taken with mixed reaction.<ref name="stevenson"/> A 2013 study conclusively identified Auger recombination as the cause.<ref>{{cite web|author=Iveland, Justin|title=Cause of LED Efficiency Droop Finally Revealed|url=https://www.sciencedaily.com/releases/2013/04/130423102328.htm|work=Physical Review Letters, 2013|date=23 April 2013|display-authors=etal}}</ref>