Red-emitting Mn4+-doped Li2MgSn2O6 phosphors for plant growth LED lighting

• Published in: Journal of molecular structure 2024-11, Vol.1316, p.139004, Article 139004
• Main Authors: Tu, Nguyen, Van Quang, Nguyen, Van Du, Nguyen, Trung, Do Quang, Bach, Ta Ngoc, Hung, Nguyen Duy, Viet, Dao Xuan, Ha, Le Tien, Hieu, Nguyen Minh, Tran, Manh Trung, Huy, Pham Thanh
• Format: Article
• Language: English
• Subjects: Li2MgSn2O6:Mn4; Phosphors; Plant growth LEDs; Solid-state reaction
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2024.139004

•A novel Mn4+-doped Li2MgSn2O6 phosphor with excellent color purity of 99.9% and good quantum efficiency of 44.5%•Strong red emissions peaking at 659 nm, achieved under excitation at 323 and 480 nm•Optimal Li2MgSn2O6:0.3%Mn4+ phosphor annealed at 1000 °C with particle size of 1.0 μm, 0.176 ms lifetime, and 0.335 eV activation energy•A prototype of NUV-pumped phytochrome-boosted plant growth LED using Li2MgSn2O6:0.3%Mn4+ phosphor In this study, a novel red-emitting Mn4+ doped Li2MgSn2O6 (Li2MgSn2O6:Mn4+) phosphors were successfully synthesized using a simple solid-state reaction method. XRD patterns indicated the replacement of Mn4+ ions with Sn4+ ions in the [SnO6] octahedrons site of the Li2MgSn2O6 lattice, and XPS spectra confirmed the Mn4+ oxidation state. Excited at 323 nm and 480 nm, the phosphors exhibited a strong red emission band peaking at 659 nm, attributed to the 2E → 4A2 transition of Mn4+ ions. Notably, the highest PL intensity was found in the Li2MgSn2O6:0.3%Mn4+ sample annealed at 1000 °C. These phosphors, with a particle size of 1.0 μm, possess a long lifetime of 0.176 ms, high activation energy of 0.335 eV, excellent color purity of 99.9%, and good internal and external quantum efficiency of 44.5% and 24.1%, respectively. Furthermore, an LED coated with Li2MgSn2O6:0.3%Mn4+ phosphor on a 365 nm NUV LED chip showed strong emission matching the absorption spectrum of the red phytochrome. Therefore, these results indicated that the synthesized Li2MgSn2O6:Mn4+ phosphors could be used as red-emitting materials for plant growth LED applications. [Display omitted]