A far-red phosphor LaSrZnNbO6:Mn4+ for plant growth lighting

Abstract The photoluminescence characteristics of LaSrZnNbO6:Mn4+ were studied in this paper. The excitation spectrum of LaSrZnNbO6:Mn4+ can be divided into two bands. The absorption band centered at 320 nm is attributed to the charge transfer transition from O2− to Mn4+, while the absorption band centered at 366 nm is credited to the 4A2 → 4T1 transition of Mn4+. The weak absorption bands centered at 432 nm and 505 nm are due to the 4A2 → 2T2 and 4A2 → 4T2 transitions of Mn4+ ions, respectively. The emission peak appeared at 694 nm, which is matched well with the absorption wavelength of phytochromes, is caused by the 2E → 4A2 transition of Mn4+ ions. With increasing the Mn4+ ion concentration, the decay times of LaSrZnNbO6:Mn4+ are decreased from 0.2694 to 0.2448 ms. The chromaticity coordinate is (0.7199, 0.2801), which is the far-red emission. The phosphor is conducive to plant growth and has potential applications in the field of plant lighting.