YF3:Ln3+ (Ln = Ce, Tb, Pr) submicrospindles: hydrothermal synthesis and luminescence properties

Abstract

YF₃:Ln³⁺ (Ln = Ce, Tb, Pr) microspindles were successfully fabricated by a facile hydrothermal method. X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), lifetimes, photoluminescence (PL) and low-voltage cathodoluminescence (CL) were used to characterize the resulting samples. The lengths and diameters of YF₃:0.02Ce³⁺ microspindles are around 760 nm and 230 nm, respectively. Adding dilute acid and trisodium citrate (Cit³⁻) are essential for obtaining YF₃ microspindles. A potential formation mechanism for YF₃ microspindles has been presented. PL spectroscopy investigations show that YF₃:Ce³⁺ and YF₃:Tb³⁺ microcrystals exhibit the characteristic emission of Ce³⁺ 5d → 4f and Tb^{3+ 5}D₄ → ⁷F_J (J = 6–3) transitions, respectively. In addition, the energy transfer from Ce³⁺ to Tb³⁺ was investigated in detail for YF₃:Ce³⁺, Tb³⁺ microspindles. Under the excitation of electron beams, YF₃:Pr³⁺ show quantum cutting emission and YF₃:Ce³⁺, Tb³⁺ phosphors exhibit more intense green emission than the commercial phosphor ZnO:Zn.