Synthesis, structure, and luminescence characteristics of far-red emitting Mn(4+)-activated LaScO(3) perovskite phosphors for plant growth.

Far-red emitting phosphors LaScO(3):Mn(4+) were successfully synthesized via a high-temperature solid-state reaction method. The X-ray powder diffraction confirmed that the pure-phase LaScO(3):Mn(4+) phosphors had formed. Under 398 nm excitation, the LaScO(3):Mn(4+) phosphors emitted far red light within the range of 650-800 nm peaking at 703 nm (14 225 cm(-1)) due to the (2)E(g) → (4)A(2g) transition, which was close to the spectral absorption center of phytochrome P(FR) located at around 730 nm. The optimal doping concentration and luminescence concentration quenching mechanism of LaScO(3):Mn(4+) phosphors was found to be 0.001 and electric dipole-dipole interaction, respectively. And the CIE chromaticity coordinates of the LaScO(3):0.001Mn(4+) phosphor were (0.7324, 0.2676). The decay lifetimes of the LaScO(3):Mn(4+) phosphors gradually decreased from 0.149 to 0.126 ms when the Mn(4+) doping concentration increased from 0.05 to 0.9 mol%. Crystal field analysis showed that the Mn(4+) ions experienced a strong crystal field in the LaScO(3) host. The research conducted on the LaScO(3):Mn(4+) phosphors illustrated their potential application in plant lighting to control or regulate plant growth.