Mn4+-doped La(CaZr)0.5O3 phosphors for plant grow LEDs: Ab initio site occupy and photoluminescence properties

Abstract The La(CaZr)0.5O3: Mn4+ (LCZ: Mn4+) phosphors are synthesized by the conventional solid-state method. The crystal structure, surface morphology, optical properties, and thermal properties of LCZ are investigated in detail. So far, the site where Mn4+ might occupy in the host is rarely discussed. Herein, we discuss the possible site of Mn4+ ions by formation energy, bond length, density of state, valence charge density, and Bader charge based on density functional theory. Compared with the host, the doped phosphor has a stronger light absorption capacity and a wider light absorption range. The doped phosphors can emit deep-red light that centered at 694 nm under the n-UV (347 nm) and blue light (530 nm) excitation at room temperature. The critical quenching concentration of Mn4+ is 0.006, and the mechanism of concentration quenching is the dipole–dipole interaction between Mn4+ ions. The photoluminescence intensity of 100 °C remains at 16.5% of the initial intensity at room temperature. What's more, the emission band of phosphors overlaps with absorption spectra of plant, indicating its potential application value in plant growing light-emitting diodes.