High Performance Colloidal Nanocrystals

One of the main roadblocks to higher efficiencies for warm-white LED light sources is spectrally-wide red-emitting bulk phosphors, which emit a significant amount of their energy either in the far red or infrared where the eye’s response is poor or zero. Consequently, employing those phosphors (along with bulk green-yellow emitting ones) will result in desired warmer light sources, however, at the expense of lower efficiency. Colloidal nanocrystals have been touted for years as a solution to this problem; however, they still suffer from unwanted quenching of the quantum efficiency and increases in their spectral width at the elevated temperatures and excitation levels that are attained during operation of high power LEDs. Previously, Lumisyn has formed a new and novel class of high efficiency non-toxic nanocrystals which overcome these long-standing problems with nanocrystals. Prior to product introduction, our nanocrystals need to further improve their efficiency, reduce their emission spectral width, and reduce the variability of their synthetic process. By targeted synthetic/compositional work in combination with appropriate optical and material characterization of our nanocrystals, Lumisyn will generate a model for the factors which enable high efficiency for our nanocrystals under both ambient and adverse (high temperatures and high excitation fluxes) LED operating conditions, in addition to identifying those compositional factors which lead to unwanted loss of nanocrystal efficiency. Lumisyn will explore both synthetic and compositional changes in order to further reduce the spectral width of Lumisyn’s red-emitting nanocrystals. Finally, by appropriate modification of our synthetic process, Lumisyn will sharply reduce the batch-to-batch variability of our synthesized nanocrystals. Using these approaches in combination with synthetic and compositional optimization, Lumisyn will further increase the efficiency of our nanocrystals under ambient and elevated temperature/flux conditions, while reducing the spectral width by ~15%. Lastly, Lumisyn will lower the variability of the nanocrystal synthetic process by approximately a factor of 3, thus further enabling the manufacture of our nanocrystals. This work will take our non-toxic on-chip nanocrystals a few steps forward toward the goal of being direct replacements for current bulk phosphors, thus enabling LED efficacy to further increase by up to a factor of 1.4, while improving the lighting color quality and enabling custom light sources. These performance advantages will enable both commercial and consumer customers to lower their general lighting energy costs, obtain higher quality lighting, and reduce their carbon footprint. The efficiency of LED-based lighting, though very good, can be nearly doubled resulting in further reduced energy costs and CO2 emissions. Lumisyn’s work will improve the efficiency of our next generation materials, so that they can be used in LED products to result in up to a factor of 1.4 increase in LED efficiency.