Enriching red emission of Y_3Al_5O_12: Ce^3+ by codoping Pr^3+ and Cr^3+ for improving color rendering of white LEDs

Abstract

Triply doped Y3Al5O12: Ce3+, Pr3+, Cr3+ phosphors are prepared by solid state reaction. The emission spectra are enriched in the red region with the luminescence of both Pr3+ and Cr3+ through Ce3+ → Cr3+ and Ce3+ → Pr3+ → Cr3+ energy transfers. The properties of photoluminescence and fluorescence decay indicates larger macroscopic Ce3+ → Cr3+ transfer rates in the triply doped phosphors in comparison to Ce3+ and Cr3+ doubly doped one, reflecting the effect of competition between Ce3+ → Cr3+ and Ce3+ → Pr3+ transfers. White LEDs fabricated using the triply doped phosphor coated on blue LED chips show a color rendering index of 81.4 higher than that either using Ce3+ and Cr3+ doubly doped or Ce3+ singly doped phosphor.

Luminescence study of a self-activated and rare earth activated Sr3La(VO4)3phosphor potentially applicable in W-LEDs

“…However, this technique has its own disadvantages such as low color-rendering index and high color temperature. [6][7][8] Another promising method for generating white light is coupling tri-color (red, green and blue) phosphors with a near ultraviolet LED chip, but the reabsorption between different kinds of phosphor is still a problem needed to be solved. 9 A solution to this problem is developing the efficient phosphor with a broad emission covering red, green and blue regions.…”

Soft-Chemistry Derived Advanced Phosphors for Smart Lighting Devices Based on Blue or UV LEDs

“…32 Moreover, a peak located at 611 nm is observed and ascribed to the Pr 3+ 1 D 2 → 3 H 4 transition. 33 The quantum yield recorded under excitation at 460 nm of such a mixture was 72%. This value is very promising in comparison with that obtained for commercial phosphors usually used in association with blue LEDs (90% for the reference QMK58/F-U1 from Phosphor Tech) that have been optimized, particularly thanks to heating treatment in reducing atmosphere, in order to reduce the Ce 4+ quantity, harmful for luminescence.…”

Luminescence studies on lanthanide ions (Gd3+, Tb3+) doped YAG:Ce phosphors by combustion synthesis

“…Therefore, blending other red-emitting phosphors into the YAG:Ce phosphor or doping other rare earth ions with a different radius to expand the YAG:Ce emission band to induce a red shift of the YAG:Ce luminescence have been proposed as solutions to this problem [8][9][10][11]. Co-doping red emitting ions as co-activators into YAG: Ce 3+ was extensively studied [12]. Substituting Y 3+ with Tb…”