Tb4o7

PLGA (M_w = 1 × 10⁵, LA : GA = 85 : 15) was purchased from Jinan Daigang Biotechnology Co., LTD (China). La₂O₃ (99%), Tb₄O₇ (99%) and benzimidazole (Bim) were purchased from Sinopharm Chemical Reagent Co., LTD (China). NaOH, FeCl₃·6H₂O and FeCl₂·4H₂O were provided by Xilong Chemical Co., LTD (China). Hydrogen peroxide (H₂O₂, 30%), hydrochloric acid (HCl), trichloromethane (CHCl₃), tetrahydrofuran (THF), dichloromethane (CH₂Cl₂) and absolute ethylalcohol were provided by Beijing Chemical Works (China). Hexafluoroisopropanol (HFIP) was purchased from Aladdin Industrial Corporation. All reagents involved in this work were of analytical grade and directly used as-received without any further purification.

The SYNPF:Tb³⁺ phosphors were synthesized by a traditional high temperature solid-state reaction. The starting materials include analytical grade SrCO₃, SrF₂, Na₂CO₃, NH₄H₂PO₄, Y₂O₃ (99.99%), and Tb₄O₇ (99.99%). The SrF₂ (A.R.), Na₂CO₃ (A.R.), and NH₄H₂PO₄ (A.R.) were purchased from Guangfu Co. Ltd, Tianjin (China), SrCO₃ (A.R.), Y₂O₃ (99.99%), and Tb₄O₇ (99.99%) were bought from Sinopharm Chemical Reagent Co. Ltd, Shanghai (China). The raw materials were weighted and thoroughly mixed homogeneously using an agate mortar for 30 min. After mixing and grinding, the mixtures were placed into a crucible and sintered at 1150 °C for 3 h with active carbon. Finally, all the samples were furnace-cooled to room temperature and reground into fine powder for further measurements.