The lumen degradation, chromaticity shift, transmittance loss, and mean-time-to-failure (MTTF) evaluation in glass- and silicone-based high-power phosphor-converted whitelight- emitting diodes (LEDs) (PC-WLEDs) under accelerated thermal aging at 150 ◦C, 200 ◦C, and 250 ◦C are presented and compared. The silicone-based PC-WLEDs exhibited less thermal stability than the glass-based PC-WLED…