Replacing inefficient fluorescent, halogen, and incandescent lighting with solid-state lighting (SSL) could reduce the amount of energy needed for lighting in 2025 by as much as 326 TWH per year (33% of predicted energy needs) and carbon emission by 42 megatons per year in the United States alone.1,2 In order to guide this transition from conventional lighting to SSL, the US Department of Energy has proposed the following targets for white SSL for general use: Commission International d'Eclairage (CIE) chromaticity coordinates of pure white light (0.33, 0.33); a high color rendering index (CRI) of >80; and a luminous efficiency (luminous flux output divided by input of electrical power) of 200 lm per watt-although it has been suggested that very high CRI values may limit efficiencies to 145 lm per watt.
In the past, hybrid electroluminescent devices have been fabricated using a single size or multiple sizes of nanocrystals combined with several organic layers to provide either a monochromatic source5,6,7 or a solid-state, white-light source.