Significant improved quantum yields of CaAl12O19:Mn4+ red phosphor by co-doping Bi3+ and B3+ ions and dual applications for plant cultivations

CaAl12O19:Mn4+ has been reported as a red phosphor with good color purity. A quaternary-doping strategy was adopted to improve the optical properties in this work. Phosphors of general formula Ca1-mAl12-x-y-nO19: xMn(4+), yMg(2+), mBi(3+), nB(3+) (CAO:MMBB) were synthesized by high- temperature solid-state method. A broad band deep-red emission from Mn4+ centered at 654 nm was observed, and two strong absorption bands within the ultraviolet range (350-400 nm) and blue-green region peaked at 460 nm were confirmed. The incorporation of co-dopants brought about a remarkable enhancement of the luminescence intensity. The quantum yield of CAO:MMBB reached 84.9%, which is approximately 1.35 times higher than that of as-reported binary-doping phosphors CaAl12-x-yO19:xMn(4+), yMg(2+) (CAO:MM). The possible mechanism of co-doping Bi3+ and B3+ ions was discussed in detailed. CAO:MMBB phosphor shows a dual application in agriculture either as solar spectral conversion auxiliary in greenhouse plastic films or as a red component in blue-chip based plant growth light emitting diodes (PG-LEDs).