Strain-Free and Thermally Stable High Power pc-White LEDs

Current pc-white LEDs made with InGaN blue-LEDs and Y3Al5O12: Ce3+ (YAG: Ce) phosphor’s luminescence suffer from low colour rendering (CRI) ~ 70%, and high colour temperature (CCT) > 5000 K because of the lack of red light, and due to the leakage of blue light, which is unhealthy. Also, lighting colour properties fluctuate with currents. In addition, the present pc-LEDs have low thermal stability at higher operating temperatures. The CSIR-NIIST has established prototypes of rigid and flexible white LEDs with the developed broadband yellow emitting phosphor.

CSIR-NIIST has developed rigid and flexible white LEDs using innovative broadband yellow-emitting phosphors to overcome limitations of current pc-white LEDs. These prototypes feature improved colour rendering (CRI), optimized colour temperature (CCT), and enhanced thermal stability.

• The white LEDs fabricated using NIIST-developed phosphors have superior colour qualities than the commercial white LEDs based on YAG: Ce.

• The developed phosphors produced strain-free warm white light with appreciable CRI (~ 80%) and lower CCT (~3500 K).

• The developed phosphors showed higher thermal stability compared to commercial YAG: Ce.

• The developed white LEDs are thermally stable and more suitable for eco-friendly general lighting.