Synthesis, structure, and luminescence characteristics of far-red emitting Mn4+-activated LaScO3 perovskite phosphors for plant growth

Abstract

Far-red emitting phosphors LaScO₃:Mn⁴⁺ were successfully synthesized via a high-temperature solid-state reaction method. The X-ray powder diffraction confirmed that the pure-phase LaScO₃:Mn⁴⁺ phosphors had formed. Under 398 nm excitation, the LaScO₃:Mn⁴⁺ phosphors emitted far red light within the range of 650–800 nm peaking at 703 nm (14 225 cm⁻¹) due to the ²E_g → ⁴A_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 LaScO₃:Mn⁴⁺ phosphors was found to be 0.001 and electric dipole–dipole interaction, respectively. And the CIE chromaticity coordinates of the LaScO₃:0.001Mn⁴⁺ phosphor were (0.7324, 0.2676). The decay lifetimes of the LaScO₃:Mn⁴⁺ phosphors gradually decreased from 0.149 to 0.126 ms when the Mn⁴⁺ doping concentration increased from 0.05 to 0.9 mol%. Crystal field analysis showed that the Mn⁴⁺ ions experienced a strong crystal field in the LaScO₃ host. The research conducted on the LaScO₃:Mn⁴⁺ phosphors illustrated their potential application in plant lighting to control or regulate plant growth.