Bidirectional energy transfer in Er 3+ /Sm 3+ co-doped BaFCl nanoparticles

Elucidating the energy transfer (ET) process and further controlling the up/down luminescence in lanthanide ion-doped luminescent materials is significant in various related fields such as color display, biomedical imaging, and quantum computing. In this work, studies were performed on the ET process in erbium (Er 3+ ) and samarium (Sm 3+ ) ions co-doped BaFCl nanoparticles by measuring luminescence from spectral and time dimensions. Efficient ET was realized via the usual Er 3+ to Sm 3+ pathway by varying Sm 3+ doping concentration, achieving high efficiency of 47%. Further analysis reveals that the ET is caused by dipole-dipole interactions. Another ET process from Sm 3+ to Er 3+ was also simultaneously observed under excitation with high laser powers. Further, the dynamic luminescence decay lifetimes of Er 3+ were verified and their mechanism was analyzed in detail. The revealed ET channel provided valuable insights and different perspectives for future research on Er 3+ /Sm 3+ co-doped nanomaterials.