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.