Multicolour upconversion emission from Ho~(3+)-Tm~(3+)-Yb~(3+) codoped CaMoO_4 phosphor

摘要

The Ho~(3+)-Tm~(3+)-Yb~(3+) codoped CaMoO4 phosphor powder has been synthesized by chemical coprecipitation technique. For the structural investigation the X-ray diffraction analysis has been done. Multicolour upconversion (UC) emission in the visible region from the prepared material has been observed under the 980 nm near infrared (NIR) excitation. The UC emission bands ～474 nm (blue), ～541 nm (green) and ～661 nm (red) region have been assigned as ~1G_4→~3H_6 (Tm~(3+)), ~5F_4~5S_2→~5I_8 (Ho~(3+)) and ~5F_5→~5I_8 (Ho~(3+)) transitions respectively.