Excellent Quantum Efficiency and Superior Color Purity Red-Emitting CaAl12O19-CaAl4O7-MgAl2O4:Mn4+ Phosphors for Plant Growth and High Color Rendering Index White Light-Emitting Diode Applications

This work reports an excellent quantum efficiency and superior color purity CaAl12O19-CaAl4O7-MgAl2O4:Mn4+(CCM:Mn4+) red-emitting phosphor. This phosphor can be excited by a broad excitation band ranging from 300 to 500 nm, and it generates an intense broadband red emission peaking at 656 nm. The CCM:0.5%Mn4+ phosphor-possessed superior color purity of 100%, a long lifetime of 0.49 ms, and high activation energy of 0.286 eV. Four different prototypes of plant growth light-emitting diodes (LEDs) with high quantum efficiencies of 81.8, 72.1, 67.2, and 61.1% were fabricated by coating the optimized CCM:0.5%Mn4+ phosphors onto UV (365 nm), NUV (395 nm), violet (410), and blue (460 nm) LED chips, respectively. The 81.8% and 72.1% QE values are the highest values reported for the 365 nm UV-pumped and 395 nm NUV-pumped LEDs based on Mn4+-doped oxide phosphors. Furthermore, a white LED with a high color rendering index (CM) of 90, correlated color temperature (CCT) of 2416 K, and luminous efficacy of radiation (LER) of 216 lm/W was realized using a blue LED chip and a mixture of CCM:0.5%Mn4+ and commercial YAG:Ce3+ phosphors. Our results demonstrate great potential for using CCM:Mn4+ phosphors for plant growth LEDs and white light-emitting diode (WLED) applications.

Automated summary

This study introduces a new red-emitting phosphor with excellent quantum efficiency and color purity, which can be widely excited to produce intense red emission, showing great potential for applications in plant growth LEDs and white light-emitting diodes.