Two targets with one strategy: Insights into the role of aluminum atoms on the luminescence properties and thermal stability in Mn4+ -doped calcium aluminozincate phosphor

Greenhouse plant cultivation (GPC) has attracted great attention in recent years, and the search for novel high efficiency far-red emitting phosphor is a crucial task. With this aim in view, in the present paper Ca14Al10Zn6O35:Mn4+ (CAZO:Mn4+) was investigated as a prototype phosphor. By simply incorporating excessive amount of Al, Ca10.25ZnO:Mn4+ can meet two criteria simultaneously: it has relatively high quantum efficiency (QE) and good thermal stability, which tackle the goal of killing two birds with one stone. The internal QE (IQE) could further enhance from 83.9% to 90.0% due to the increased occupancy capability of Mn4+ in [AlO6] octahedron, which is evidenced by solid-state Al-27 nuclear magnetic resonance (NMR) and energy dispersive spectra (EDS) measurements. In addition, the Mn4+ concentration-dependent excitation and emission spectra also demonstrate that the optimal doping concentration of Mn4+ in CA(10.25)ZO host increases from 0.15 to 0.17 mol. Moreover, compared with CA(9.85)ZO:0.15Mn(4+), the thermal stability of CA(10.25)ZO:0.15Mn(4+) improves from 55% to 58% at 150 degrees C and 38%-45% at 200 degrees C, respectively. The as-fabricated plant growth LED devices shows better potential to be applied in GPC. This design strategy shown here provides an alternative pathway to further improve the luminescence properties of phosphors. (C) 2020 Elsevier B.V. All rights reserved.