Improving efficiency and light quality of white LEDs by adding ZrO2 nano-particle and red phosphor in encapsulant

Abstract

Efficiency and light quality of white light-emitting diodes (LEDs) were improved by adding ZrO2 nano-particle and red phosphor in encapsulant. ZrO2 nanoparticles can enhance the light scattering ability of encapsulant on LED chip. Doping ZrO2 nanoparticles with YAG phosphor into encapsulant package (LED II) luminous flux increase of 7.7 % compared conventional doping YAG phosphor package (LED I). Conformal YAG phosphor on LED chip and doping ZrO2 nanoparticles into encapsulant package of white LED (LED III) the luminous flux increase of 19.8 % compared LED II. Doping red phosphor into encapsulant of LED II produced LED IV, CRI can improved from 47 to 90 and R9 from 0 to 90.