Site occupancy and tunable luminescence of Eu and Eu coactivated KCaY (PO):Eu phosphors.

Utilizing the structure characteristic of KCaY (PO) crystal, the site distribution of Eu in KCaY (PO):Eu phosphor coactivated with Eu and Eu ions is tuned. Upon 393-nm excitation, the as-prepared phosphor exhibits a broadband emission of Eu peaked at ~ 475 nm and a typical red emission of Eu with a strong D-F emission at ~ 591 nm. The luminescence color of the phosphor can be adjusted from blue to green, white, yellow, and red. The increasing concentration of Sr and Eu results in a blue shifting of Eu emission. The increasing concentration of Eu results in a red shifting of Eu emission and an enhanced red emission of Eu. The luminescence behaviors of the phosphors are analyzed in terms of the site distribution of Eu and Eu. A single-phase white light emitting was achieved in KCaY (PO):Eu phosphor upon UV and NUV light excitation, indicating that the phosphor has potential application in white lighting.