Anomalous emission of Yb2+in CaF2:Tb3+, Yb3+up-conversion phosphor

Anomalous emission of ytterbium (Yb2+) was observed in terbium (Tb3+)-Yb co-doped CaF2 up-conversion nanophosphor. The anomalous emission of Yb2+ is a phenomenon observed, where the Yb2+ ion emits light with a longer wavelength than expected. This phenomenon has attracted significant attention due to its potential applications in a range of fields, including optical communication, sensing and imaging. In this study the presence of Yb2+ ions was confirmed by X-ray photoelectron spectroscopy. The existence of the anomalous emission of Yb2+ in CaF2:Tb3+-Yb significantly influenced the blue emission of the Tb3+ ions due to the upconversion process. The addition of lithium ions as charge compensators into the system decreased the anomalous emission of the Yb2+ ions. Therefore, understanding the mechanism of this anomalous emission of Yb2+ ions in CaF2:Tb3+-Yb and other materials with enhanced emission properties could have significant technological applications.