When UV/Blue LEDs are downconverted to white light, the best luminous efficiency is reported to be in the range of 25 to 45 lumens/watt (lm/W). This can be increased to 75 lm/W by using three individual blue, green, and red LEDs, but this is expensive. For white light LED lamps to be widely accepted, the cost of the lamps must be reduced by 10 times while still providing a luminous efficiency of 75 lm/W. To date, the low downconversion efficiency of existing phosphors has prevented the achievement of this goal. This project will utilize a new class of downconverter nanophosphors to efficiently absorb UV/Blue light and simultaneously downconvert to white light. When fully optimized, the nanophosphors are expected to increase white light emission by 100%, bringing the luminous out-put of UV/Blue LEDs to 75 lm/W. Phase I will develop Quantum Confined atom-based nanophosphors for excitation in the range 370 to 450 nm. Both line-emitter and broadband nanophosphors will be provided. The Synthesis and Integration of Quantum Confined Atom (QCA) Nanophosphor based Downconverter for AlInGaN based High Luminous Efficiency White-Light LED Lamps would help us to achieve the targeted luminous efficiency of 75 lm/W.
Commercial Applications and Other Benefits as described by the awardee: The high down conversion efficiency of quantum confined atom based nanophosphors should lead to an inexpensive LED package that would reduce the cost of white LED lamps considerably without sacrificing performance
