Sr3LiTaO6:xMn4+ red-emitting phosphors for indoor plant growth lighting: High thermal stability and quantum efficiency

Abstract A series of Sr3LiTaO6:xMn4+ red-emitting phosphors were synthesized by high temperature solid-state method for the first time. The samples were characterized using XRD, SEM, PLE, PL, UV–vis spectra, and internal quantum efficiency (IQE). The Sr3LiTaO6:0.2%Mn4+ phosphor exhibited a strong emission peak at 695 nm with a maximum IQE of 61.46%, which is suitable for use in indoor plant application. The intense excitation band of the phosphor located at the near ultraviolet region, which can match well with the emission of commercial ultraviolet LED chip. Moreover, the CIE chromaticity coordinate of Sr3LiTaO6:0.2%Mn4+ phosphor is (0.730, 0.270), which falls in deep red range with a color purity of 98.7%. The Sr3LiTaO6:0.2%Mn4+ phosphor also showed a good thermal stability with an emission intensity decrease of only 23.3% at 423 K from that at 289 K ( I 423 K / I 289 K = 76.7 % ). Finally, a LED device was fabricated for light supplement on wheat, showing an obvious improvement on the content of chlorophyll. It shows that the optimized phosphor may have a good potential for the application in indoor plant growth lighting LEDs.