New Phosphors for UV LED Solid-State Lighting for Solid State Lighting Core Technology for Light Emitting Diodes (LEDs)

Electrical lighting consumes ~22% of the electricity in the U.S., which amounts to more than a third of total energy consumption. With the increasing effectiveness of light emitting diodes (LEDs), the long-term forecast is for the eventual replacement of most traditional lights, both incandescent and fluorescent, with more efficient solid-state LED lighting. However, the unavailability of a broad array of phosphors, which can be excited by UV or near-UV light with high quantum efficiency and long-term stability, is an imposing challenge for solid-state lighting. In principle, the emission wavelength of GaN-based LEDs can be increased from 370nm (pure GaN) to 470nm by increasing the indium content in InGaN solid-state devices; conversely, the emission wavelength can be lowered to 254 nm by increasing the aluminum content in AlGaN devices. Nonetheless, few phosphors exist that can be tailored to the specific emissions of these InGaN and AlGaN devices. This project will develop new phosphors for such LED applications, based on a class of materials that can be tailored to the specific emissions of these devices. Phase I will (1) optimize the quantum efficiencies of various self-activated phosphor compositions, (2) control the excitation spectra for phosphor compositions with activators in the near-UV; and (3) determine the long-term stability and quality of the materials. Commercial Applications and other Benefits as described by the awardee:The new phosphors should speed the replacement of standard incandescent and fluorescent bulbs with advanced LED technology. The technology should lead to SSL products with decreased cost and increased color quality.