Hydrothermal Synthesis Y 2 O 3 :Yb 3+ /Er 3+ Nanospheres with Upconversion Luminescence from Green to Red

Well-dispersed, uniform Y 2 O 3 :Yb 3+ /Er 3+ nanospheres have been successfully prepared at 160°C via a facile hydrothermal route without using any templates, followed by a subsequent calcination process. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and upconversion photoluminescence spectra were employed to characterize the samples. The SEM and TEM images indicate that the samples consist of separated spheres with a mean diameter of about 75 nm. Under the excitation of 980-nm laser, the Y 2 O 3 :Yb 3+ /Er 3+ phosphors exhibit bright upconversion photoluminescence from green to red with different Yb3+ content, which is easily observed by our naked eyes. Due to multicolor tunable luminescence, ideal spherical shape, and cheap materials of Y 2 O 3 host, the as-prepared phosphors are potentially applied for color displays, back light, UC lasers, photonics, and biomedicine.