Microporous Alumina Confined Nanowire Inorganic Phosphor Film for Solid State Lighting

The low efficiency of current illumination devices wastes electrical energy. In addition, these devices are expensive to produce, their white light output is low, and they (and/or the production of them) present environmental hazards. This project will address these limitations by developing new phosphors for solid-state lighting, based on particles of luminescent material confined in a nanoporous matrix. The resulting devices will offer higher (20-30%), white-light conversion efficiency without generating hazardous waste during production. The efficiency increase for the device is related to the high fluorescence quantum efficiency of the phosphor and is due to: (1) less reabsorption in the nanocrystals, which have large molar absorptivity; and (2) a decrease in the optical trapping of emissions inside the phosphor layer, because of the high refractive index of the matrix. The phosphors will be incorporated into solid-state lighting devices on the emitting surface of light-emitting chips in the same manufacturing line, without epoxy or organic binder. Phase I will involve the fabrication of the proposed phosphor, including the construction of alumina templates and the deposition of nanowire phosphor material on the templates. The phosphors obtained will be subjected to testing for optical absorption, luminescence brightness, spectra, and conversion efficiency. Commercial Applications and other Benefits as described by the awardee: The technology should have wide commercial application for the production of high-brightness white-light sources for residential and commercial illumination, providing increased efficiency (at least 20%) and a reduced price compared to existing devices. In addition to the higher brightness and lower energy consumption, the end user should benefit from longer device lifetimes that will save money in terms of maintenance and lamp replacement. Advantages for manufacturers would include a simple, environmentally safe manufacturing process with with higher yields and no chemically aggressive waste.