http://ieeexplore.ieee.org TOC Alert for Publication# 9425 2013 May 16 $R _{a}$'s) and color temperatures (CTs). We find that, except for the very highest color rendering indices, the spectra are spiky rather than continuous. We present a useful analytic expression for the dependences of the maximum white luminous efficacy of radiation (MWLER) on $R _{a}$ and CT and discuss these dependences. We propose that, for any white light source of a given $R _{a}$ and CT, its absolute spectral efficiency is simply the ratio of its LER to the MWLER at that same $R _{a}$ and CT. We discuss the absolute spectral efficiency, defined in this way, of various lighting technologies: incandescent, fluorescent, high-intensity discharge, and solid-state lighting. Finally, we discuss the possibility of alternative MWLERs based on alternative indices for color rendering quality.]]> 9 6 405 412 1545 9 6 413 418 374 9 6 419 426 1163 $^{circ}{hbox{C}}$. This is a considerable high operating temperature for a phosphor layer in the PC-WLEDs. The lumen degradation, chromaticity shift, and transmittance loss in the glass-based PC-WLEDs under thermal aging at 150 $^{circ}{hbox{C}}$ , 250 $^{circ}{hbox{C}}$ , 350 $^{circ}{hbox{C}}$ , and 450 $^{circ}{hbox{C}}$ are also presented and compared with those of silicone-based PC-WLEDs under thermal aging at 150 $^{circ}{hbox{C}}$ and 250 $^{circ}{hbox{C}}$ . The result clearly demonstrated that the glass-based PC-WLEDs exhibited better thermal stability in lumen degradation, chromaticity shift, and transmittance loss than the silicone-based PC-WLEDs. The advantages of glass encapsulation in high-temperature operation of the PC-WLEDs could be explained that the glass transition temperature of the glass phosphor (567 $ ^{circ}{hbox{C}}$) was much higher than it of silicone (150 $ ^{circ}{hbox{C}}$). The newly developed ultra-high thermal-stable glass is essentially critical to the application of LED mo- ules in the area where the high-power, high-temperature and absolute reliability are required for use in the next-generation solid-state lighting.]]> 9 6 427 432 1125 ${-}{hbox{80}}^{circ}$ to 0$^{circ}$, and a CCT variation of only 45 K was detected, while the multilayer phosphor coating had higher color rendering capabilities, reaching a ${rm CRI}_{rm general}$ value as high as 85.6. A promising guideline found through this work is that the pulse-sprayed conformal phosphor configuration would particularly be able to improve the light quality of LED devices by a significant amount: the mixed phosphor configuration achieves excellent CCT homogeneity, and the multilayer phosphor configuration reveals a novel concept for fabricating a low-CCT and high-CRI LED device with less nitride phosphor. The findings of our research should provide valuable insight to LED indust- ies.]]> 9 6 433 440 1252 $Delta E$ was 1.2%. Meanwhile, the difference of correlated color temperature limited from 1 wt% to 5 wt% phosphor concentration between the simulation and measurement was 184 K. Such a model for glass phosphors will be helpful to design high-power glass-based pc-WLEDs.]]> 9 6 441 446 1019 9 6 447 452 1524 9 6 453 458 685 9 6 459 468 1287 9 6 469 475 1210 9 6 476 482 757 ${hbox{cd}}/{hbox{cm}}^{2}$ for the two complementary WPLEDs, and 35.7 cd/A at 3000 ${hbox{cd}}/{hbox{m}} ^{2}$ for the three complementary color WPLEDs. The current efficiencies remain high even at brightness levels up to 30,000 ${hbox{cd}}/{hbox{m}} ^{2}$. The high current efficiency is ascribed to the improved electron injection ability from the metal cathode, the enhanced charge carrier transport ability and the enhanced red emitting intensity by blending with PEG-DME. Also the low roll-off of the current efficiency was due to the lower triplet-polaron annihilation and the electric field-induced triplet exciton quenching by increased charge carrier transport in unipolar device and broadened recombination zone. The improved charge carrier injection at the interface and the enhanced charge carrier transport were resulted from specific interfacial interactions between PEG-DME and aluminum and higher electric field by blending with PEG-DME.]]> 9 6 483 489 929 $^{circ}{hbox{C}}$, the devices showed the best luminous properties with external quantum yield of 3.39%, $L _{rm ELmax}$ of 6.78 cd/A and color coordinate of (0.29, 0.30). Furthermore, the color coordinates remained almost unchanged over the range of operating potentials. The main operating process involve in the white electroluminescent process can be attributed to the direct charge trapping on the narrow band gap units and partial energy transfer from the blue-emitting segments to the green- and red-emitting siloles moieties.]]> 9 6 490 496 536 9 6 497 503 1063 9 6 504 510 1087