Enhanced far-red luminescence in Ca14Al10Zn6O35:Mn4+, Mg2+ phosphors via local structure modulation

Far-red light (700–800 nm) plays a vital role in promoting photosynthetic activity and regulating photomorphogenesis in controlled-environment agriculture. However, the development of efficient far-red phosphors remains a significant challenge. In this study, a high-performance far-red emitting (Ca,Mg) 14 Al 10 Zn 6 O 35 :Mn 4+ (CMAZO:Mn 4+ ) phosphor, was developed via a cationic substitution strategy. Upon blue light excitation, CMAZO:Mn 4+ exhibits bright far-red emission centered at 720 nm, aligning well with the absorption spectrum of phytochromes . The partial substitution of Ca 2+ by smaller Mg 2+ ions in the Ca 14 Al 10 Zn 6 O 35 :Mn 4+ (CAZO:Mn 4+ ) lattice induces lattice shrinkage and enhances structural rigidity , thereby effectively suppressing nonradiative relaxation pathways. As a result, CMAZO:Mn 4+ achieves an emission intensity 1.22 times greater than that of CAZO:Mn 4+ and demonstrates enhanced thermal stability. At the optimal Mg 2+ doping content, the phosphor reaches a quantum efficiency of 84.0 %. Notably, at 423 K, it maintains 86 % of its room temperature emission intensity. The pc-LED device, fabricated by integrating CMAZO:Mn 4+ C with an InGaN blue chip, demonstrates excellent photoelectric performance. These results suggest that CMAZO:Mn 4+ is a promising far-red luminescent material for advanced indoor plant lighting applications. • A novel far-red (Ca,Mg) 14 Al 10 Zn 6 O 35 :Mn 4+ phosphor was synthesized via solid-state reaction. • Mg 2+ substitution induces lattice contraction and enhances crystal rigidity , effectively suppressing non-radiative transitions. • The optimized phosphor shows a high quantum efficiency of 84.0 % and excellent thermal stability (86 % at 423 K). • A prototype pc-LED device exhibits stable far-red output and high color purity under high driving current.