New Class of Quantum Dots Makes the Leap from SBIR Project to Small-Business Market Success
Renaissance Lighting, an American small business headquartered in Herndon, Virginia, showcased the SoliaTM lamp, an innovative downlight, at the May 2010 LIGHTFAIR, becoming the first manufacturer to apply a new phosphor-converted LED technology with superior lumen efficacy and color rendering, and offering warm color temperatures. What was the back story behind this promising product introduction? An SBIR-funded research project initiated by Nanomaterials & Nanofabrication Laboratories (NN-Labs, LLC) in 2007.
A cost-effective pathway to creating white LED light, phosphor-converted approaches (pc-LEDs) use a blue-emitting LED die and surround it with a yellow-emitting phosphor powder. The SBIR project addressed the serious challenge of improving the light extraction efficiency—or "package efficiency"—of pc-LEDs. Light extraction had been hampered by poor refractive index matching at the die-encapsulant interface and by back-scattering from the bulk phosphor layer.
NN-Labs researchers solved both problems by incorporating high quantum efficiency doped nanocrystal quantum dots (D-dotsTM) into high-index TiO2 using sol-gel techniques. The resulting scatter-free nanophosphor composites, when embedded into a high-index material, can achieve near index matching with the LED die. Furthermore, D-dotsTM are free of toxic heavy metals, such as the cadmium found in intrinsic nanocrystal emitters.
The D-dotsTM, manufactured in Arkansas, have been incorporated by NNCrystal, a wholly owned subsidiary of Hangzhou Najing Technology, into high quality colloidal nanocrystals called Qshift Lucid. Renaissance Lighting combined Qshift with its patented Constructive Occlusion® optical technology to produce a tunable optic emitter providing 1,600 lumens, an output 30 percent greater than that achieved by comparable phosphor solutions.