LaBaMg(Ti0.5W0.5)O6:Mn4+ for plant growth lighting: Luminescence properties and synthesis

Abstract

With the need of food safety and high yield, new luminescent materials with promoting plant photosynthesis have attracted more and more attention. In this research, we synthesize the far-red-emitting LaBaMg(Ti0.5W0.5)O6:Mn4+ phosphor in air. We investigate the crystal structure and phase, particle morphology and size, and the luminescence properties. The samples show a broad excitation spectrum under monitored 704 nm due to the Mn4+ - O2− charge transfer (CT) and the transitions 4A2g → 4T1g, 2T2g, and 4T2g of Mn4+ in the range of 300 – 600 nm. The far-red emission of sample is observed with the emission spectrum (650 – 790 nm) is attributed to the Eg → 4A2g transitions. The chromaticity coordinates are (0.7329, 0.2671). The crystal field strength (Dq), the Racah parameters (B and C), and Dq/B values are ∼ 1972 cm−1, 596 cm−1, 3219 cm−1, and 3.31, respectively. 0.2 mol% is the optimal Mn4+ concentration. Emission spectra under excitation wavelength from 320 nm to 560 nm and time-resolved emission spectra confirm the only luminous center (Mn4+) in LaBaMg(Ti0.5W0.5)O6:Mn4+. Lifetime reduces with added Mn4+ concentration. The temperature-dependence emission spectra confirm that sample has a good thermo-stability. The thermal quenching phenomenon and luminous mechanism are analyzed. The luminescence properties of sample infer its application prospect in plant growth light-emitting diode (LED).