Sintering temperature and atmosphere modulated evolution of structure and luminescence of 2CaO-P2O5-B2O3: Eu phosphors

Europium doped 2CaO-P2O5-B2O3 phosphors prepared via high temperature solid state reactions are reported. The evolution of luminescence and structure of the phosphors induced by variation of sintering temperature and atmosphere is investigated using photoluminescence spectra and X-ray diffraction techniques. We found that the optical performance and structure of the phosphors are sensitive to the sintering temperature and atmosphere. The luminescence intensity due to 5D0 → 7F2 transition of Eu3+ is decreased with increasing sintering temperature. CaBPO5 and BPO4 crystals co-exist in the as-prepared phosphors and the relative content of these two phases is dependent on sintering temperature. CaBPO5 crystal favors the transition of 5D0 → 7F1 of Eu3+ ions, while BPO4 enhances the emission of 612 nm. This study gives insight into the correlation between optical properties and structure of the as-prepared phosphors. The phosphors reported here are good candidates for light emitting diode applications.