High-efficient and thermal-stable Ca19Zn2(PO4)14: Eu2+, Mn2+ blue-red dual-emitting phosphor for plant cultivation LEDs

A series of dual-emitting Eu2+, Mn2+ co-doped Ca19Zn2(PO4)14 (CZP) phosphors capable for plant cultivation LEDs are synthesized. As a sensitzer, Ca19Zn2(PO4)14: Eu2+ emits a dominant blue light with green shoulder by Eu2+ occupying CaO8 and CaO6 sites, respectively. Mn2+ was introduced into CZP: Eu2+ to obtain the red emission component. The as-synthesized CZP: Eu2+, Mn2+ phosphor shows a blue emission peaking at 415 nm and significantly enhanced deep-red emission peaking at 650 nm under single UV excitation, which should be attributed to the existence and energy transfer of Eu2+ and Mn2+, respectively. The emission spectra match well with the plants’ photosynthetic action spectra (PAS) for both red and blue lights simultaneously. Energy transfer from Eu2+ to Mn2+ enables a facile tune of emitting color from blue to red, and the corresponding mechanism is revealed to be the electric dipole-dipole interaction by analyzing Eu2+/Mn2+ decay lifetime variations. High quantum efficiency (93.3%) and favorable thermal stability (68% of RT intensity at 473 K) clearly verify the good properties of CZP: Eu2+, Mn2+ phosphor. Results confirmed that CZP: Eu2+, Mn2+ phosphor might have great applicational potential in plant growth LED lighting.