VUV spectroscopic properties of Ce3+ and Pr3+-doped AREP2O7-type alkali rare earth diphosphates (A=Na, K, Rb, Cs; RE=Y, Lu)

Spectroscopic properties of Ce3+ and Pr3+-doped AREP2O7-type alkali rare earth diphosphates (A=Na, K, Rb, Cs; RE=Y, Lu) have been investigated using VUV spectroscopy technique. Ce3+-doped samples show typical Ce3+ emission in the range of 325-450 nm. The strong host absorption band starting at around 160 nm indicates that the optical band gap of AREP2O7 hosts is at least 7.7 eV, and the host→Ce3+ energy transfer process is rather efficient. However, AREP2O7:Pr3+ samples show less efficient host→Pr3+ energy transfer. The direct Pr3+ 4f2→4f15d1 excitation, which are 12160±640 cm−1 higher respect to that of Ce3+, leads to strong 4f15d1→4f2 emission bands in the range of 230-325 nm but no obvious 4f2→4f2 emission lines.