Charge compensation assisted enhanced photoluminescence derived from Al3+-codoped NaLaMgWO6:Mn4+ phosphors for plant growth lighting applications

Abstract A novel red-emitting phosphor NaLaMgWO6 (NLMWO):xMn4+ has been synthesized by a high-temperature solid-state reaction. The samples were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), photoluminescence excitation (PLE) and emission (PL) spectra. The results indicated that the phosphors could be efficiently excited by the near ultraviolet (NUV) and blue light. Due to the 2Eg → 4A2g transition of Mn4+ ion, the samples can exhibit red emission, which was consistent with the absorption spectrum required for plant growth. In addition, the concentration quenching mechanism was dipole-quadrupole (d-q) interaction of Mn4+ activator, when the optimal doping concentration of Mn4+ was determined to be 30 mol%. Moreover, the influence of Mn4+ and Al3+ ions co-doped on the PL properties of NLMWO were studied. The PL intensity of NLMWO:0.001Mn4+, 0.002Al3+ is 1.77 times than that of NLMWO:0.003Mn4+ phosphor. The results illustrated that the PL intensity of phosphors can be greatly improved via charge compensation. The obtained results validated that NLMWO:Mn4+ can be used as a new type of red luminescent powder absorbed by plant photosensitive pigment PFR to promote plant growth.