Effect of Red-emitting Sr_2.41F_2.59B_20.03O_74.8:Eu_0.12,Sm_0.048 Phosphor on Color Rendering Index and Luminous Efficacy of White LEDs

Abstract

Color rendering index (CRI) and luminous efficacy (LE) are two key performance factors of white LEDs (WLED). While most recent works in optics focus on methodology to improve these factors, little attention has been dedicated to chemical composition of materials. This paper studies the effect of Sr2.41F2.59B20.03 O74.8:Eu0.12,Sm0.048 phosphor (SrSm), in terms of concentration and particle size on CRI and LE of 8500 K -WLEDs. Importantly, the molar mass of the componential ions in SrSm are calculated to shed light on the connection between the chemical composition of the material of interest and the performance of WLEDs. Results show that CRI can be improved to a value of around 86 by boosting red-light components in WLEDs, for all 3 major configurations: conformal, in-cup, and remote phosphor. CRI value tends to decrease with larger size of particles, while LE value goes in the reverse direction. On the other hand, both CRI and LE appear to be reduced at higher concentration of SrSm. This light attenuation is analyzed by using the Lambert-Beer law and Mie-scattering theory.

Efficient bright green phosphor for white light-emitting diode using in backlight application

“…The materials of phosphor down-conversion for diodes emit white illumination white light-emitting diodes (WLEDs) have been significantly critical to the light emitting diode (LED) industry since the WLED has been an increasingly indispensable part of modern lighting applications. In comparison with other conventional light sources like halogen lamps or fluorescent lamps, the WLED possesses various outstanding features including compactness, power-saving, environmental friendliness, and strong luminosity [1]- [3]. The WLED utilizing phosphor down-transformation to create white illumination requires more studies and development on the phosphor to serve several lighting purposes.…”