Large-scale synthesis of Lu2O3:Ln3+ (Ln3+ = Eu3+, Tb3+, Yb3+/Er3+, Yb3+/Tm3+, and Yb3+/Ho3+) microspheres and their photoluminescence properties

In this work, multicolor and monodisperse Lu2O3:Ln3+ (Ln3+ = Eu3+, Tb3+, Yb3+/Er3+, Yb3+/Tm3+, and Yb3+/Ho3+) microspheres were prepared by a homogeneous precipitation method followed by a subsequent calcination process. X-ray diffraction (XRD), Fourier transformed infrared (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) spectra, and cathodoluminescence (CL) spectra were employed to characterize the samples. Upon ultraviolet and low-voltage electron beams excitation, Lu2O3:Ln3+ (Ln3+ = Eu3+ and Tb3+) samples exhibit respective bright red (Eu3+, 5D0 → 7F2) and green (Tb3+, 5D4 → 7F5) down-conversion (DC) emissions. Under 980 nm NIR irradiation, Lu2O3:Ln3+ (Ln3+ = Yb3+/Er3+, Yb3+/Tm3+, and Yb3+/Ho3+) exhibit characteristic up-conversion (UC) emissions of green (Er3+, 4S3/2, 2H11/2 → 4I15/2), blue (Tm3+, 1G4 → 3H6) and yellow-green (Ho3+, 5F4, 5S2 → 5I8), respectively. These finding may find potential applications in bioanalysis, optoelectronic and nanoscale devices, field emission displays, and so on.