Fluorescent properties of a green- to red-emitting Eu3+, Tb3+ codoped amorphous calcium silicate phosphor

A Eu3+, Tb3+ codoped amorphous calcium silicate phosphor was prepared by heating a Eu3+, Tb3+ codoped calcium silicate hydrate phosphor formed by liquid-phase reaction for 30 min at 900 °C. The excitation peak wavelength of the resulting phosphor was 379 nm and the emission peak wavelengths were at 542 nm, attributed to the 5D4→7F5 transition of Tb3+, and at 613 mm, attributed to the 5D0→7F1 transition of Eu3+. The intensity ratio of the two peaks could be freely controlled by varying the Eu/Tb atomic ratio of the Eu3+, Tb3+ codoped amorphous calcium silicate phosphor, allowing light to be emitted over a wide range from green to red. It was clarified that electron transfer from Tb3+ to Eu3+ is occurring.