Hydrothermal synthesis and luminescence properties of octahedral LiYbF4: Er3+ microcrystals

LiYbF4: Er3+ octahedral microcrystals have been successfully prepared through a facile hydrothermal method assisted with EDTA (ethylenediaminetetraacetic acid). X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric and differential scanning calorimeters (TG-DSC), photoluminescence (PL) spectra are used to characterize the samples. Under 976 nm excitation, the upconversion (UC) luminescence emission spectra of LiYbF4: Er3+ microcrystals show the characteristic Er3+ emissions. The results show that the infrared light emissions at 792 nm of 4I9/2 → 4I15/2 are dominantly strong unusually, while the green emissions at 526 and 545 nm assigned to 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2, respectively, and the red emission at 667 nm of 4F9/2→4I15/2 are relatively weaker. Most importantly, the samples show more efficient luminescence with further heat treatment.