Site occupation, emission color tuning and white LED application of Ce3+-activated chloroborate Ca2BO3Cl

Investigation on Ce3+ ions occupying different cation sites of a specific compound is of great significance for exploring multicolor phosphors. Herein, we report the luminescent properties of Ce3+ in chloroborate Ca2BO3Cl host. Two kinds of Ce3+ f-d transitions have been observed via adjusting the doping concentration. The assignment for different Ce3+ sites to certain cation sites is corroborated by structural analysis (XRD), fluorescence spectroscopy (PL) and decay kinetic analysis. Information on the two Ce3+ sites' wavelengths of the five 5d bands in the Ca2BO3Cl host lattice together with εcfs, ɛc, D and ΔS are obtained. Moreover, with the increasing of Ce3+ doping concentration, the emission peak shows an obviously redshift, and the emission color changes from dark blue to blue. The tuning luminescence properties are attributed to the energy transfer from Ce II to Ce I. The optical properties of the as-fabricated white light-emitting diode (LED) are studied. However, the optical properties of current studied Ce3+ doped Ca2BO3Cl is not good enough to be a candidate for near-UV chip excited phosphor-converted white LED.