Effects of Pr3+ -activated BaZrGe3O9@TiO2 phosphor compound on light emitting diodes validated by computer simulation

Abstract

The Pr<sup>3+</sup> -doped BaZrGe<sub>39</sub> gallogermanate phosphors are reported to have a well-defined successive deep defect structure that effectively mitigates thermal carrier fading. This phosphor also presents a red emission with a peak at 615 nm, originating from the Pr<sup>3+</sup> transtition from <sup>1</sup>D<sub>2</sub> to <sup>3</sup>H<sub>4</sub>. We investigated the impact of Pr<sup>3+</sup> -activated BaZrGe3O9 (referred to as BZG:Pr) on the lighting characteristics of light emitting diodes (LED) packages in this paper. By combining BZG:Pr with TiO<sub>2</sub> particles and silicone, we produced a phosphor layer (designated as BZG:Pr@TiO<sub>2</sub>). The optical performance of the resulting LED was systematically examined by varying the TiO<sub>2</sub> doping percentage. Our findings reveal that the incorporation of the BZG:Pr phosphor enhances the red spectral component, thereby contributing to improved homogeneity in color distribution. However, a progressive increase in TiO<sub>2</sub> content within the phosphor layer corresponds to diminishing luminous output and decreased chromatic rendering efficiency of the LED. Employing a lower concentration of TiO<sub>2</sub> proves advantageous, as it capitalizes on the scattering-enhancing attributes while leveraging the red emission of the BZG:Pr phosphor. This synergistic approach yields a favorable balance between luminosity and color quality, enhancing the LED’s overall performance.