Advanced Phosphor Technologies For Energy Efficient Lighting And Energy Harvesting

Although fluorescent and incandescent lighting consumes >50% of the lighting energy budget, they are relatively inefficient, losing ~37% and 85%, respectively, of their energy to the IR. Thus, phosphors that could efficiently up-convert IR radiation to visible light would have a significant impact on lamp efficiency and design. This project will develop technology to increase the efficiency of upconversion phosphors by more than an order of magnitude: from ~ 5% to 60% or higher. Phase I demonstrated, both experimentally and theoretically, that an upconverting nanophosphor could improve up-conversion efficiency by a factor of 4 (experiment) or by a factor greater than 10 (theory) compared to conventional particles. In these nanostructures, both the sensitizer and activator doping were confined to two-dimensioal layers, thus dramatically enhancing upconversion efficiency while simultaneously reducing sensitizer-defect interactions. In Phase II, these nanostructured materials will be encapsulated to achieve enhanced performance that is close to the maximum theoretical efficiency. Unwanted radiative losses will be inhibited by incorporating these structures into Bragg resonator or photonic crystal structures. Finally, a low-cost, high-volume, automated manufacturing process will be developed. Commercial Applications and other Benefits as described by the awardee: The nanophosphors should have applicability to all existing lamp products, including incandescent, tungsten-halogen, and all types of fluorescents lamps. Potentially the technology could result in an annual national energy saving (commercial plus residential) of 0.979 quads, which translates into a reduction of 15.99 million metric tonnes of carbon. Additionally, the technology could significantly enhance the performance of solar cells by folding more of the solar spectrum into the operational range of the power cell.