Progress in SSL Energy Efficiency

Progress in SSL Energy Efficiency

Solid-state lighting efficiencies have increased steadily over the past 6 years and, as illustrated by the tan circles in the Figure, are now greater than those of incandescent and fluorescent lamps. They are, however, still only ~20%, and there is thus much room for further improvement. The DOE Office of Energy Efficiency and Renewable Energy’s SSL program targets an efficiency of 50%, and our research team recently discussed the feasibility of “ultra-efficiencies” of 70%, or greater [2]. Indeed, as is drawn in Fig. 1, there is the tantalizing possibility that higher functionality light (see below) might increase the “effective” efficiency of lighting beyond 100% by an additional 25-50%.

We have identified four limitations facing solid-state lighting and explain how fundamental scientific understanding could help overcome these “technology challenges.”

Historical evolution of SSL efficiency and possibilities for future evolution.

References

[1] Tsao, Jeffrey Y.; Waide, Paul. The World’s Appetite for Light: Empirical Data and Trends Spanning Three Centuries and Six Continents, LEUKOS 6, 259-281 (2010). [10.1582/LEUKOS.2010.06.04001]

[2] Phillips, Julia M.; Coltrin, Michael E; Crawford, Mary H.; Fischer, Arthur J.; Krames, Michael R.; Mueller-Mach, Regina; Mueller, Gerd O.; Ohno, Yoshi; Rohwer, Lauren E. S.; Simmons, Jerry A.; Tsao, Jeffrey, Y. Research challenges to ultra-efficient inorganic solid-state lighting, Laser & Photon Rev., 1, 307 (2007). [10.1002/lpor.200710019]