Europium
Europium, the most excitable Lanthanide element, is desireable due to its photon emission. Excitation of the Europium atom, by absorption of electrons or by UV radiation, can result in changes in energy levels that create a visible emission. Almost all practical uses of Europium utilize this luminescent behavior.

This emission of visible radiation provides the perfect red phosphors used in color televisions and computer screens around the globe. Europium is also seen in fluorescent lighting which cuts energy use by 75% compared to incandescent lighting.

Europium is also used by the medical field as the highly sensitive luminescence provided by Europium attached as a tag to complex biochemicals assists in live tracing of these materials during living tissue research.