Energy transfer and thermal regression mechanism of color-tunable phosphor Sr8La2(PO4)3.5(SiO4)2(BO4)0.5BO2: Ce3+, Tb3+.

A series of phosphosilicate phosphors Sr 8 La 2 (PO 4 ) 3.5 (SiO 4 ) 2 (BO 4 ) 0.5 BO 2 : Ce 3+ , Tb 3+ are synthesized by solid-state reaction for the first time. The XRD Rietveld refinement presents that the compound crystallizes in a trigonal crystal system with space group P 3 ¯ (No. 147). Under the excitation of 340 nm, commonly blue and yellowish green emissions from Ce 3+ and Tb 3+ are detected and can generate the color-tunable light with chromaticity coordinates from (0.188, 0.095) to (0.351, 0.517) by changing the ratio of Ce 3+ /Tb 3+ . By the photoluminescence spectra, decay times and energy transfer efficiency, the mechanism of energy transfer between Ce 3+ and Tb 3+ has been carefully investigated. With the increase of temperature, the Ce 3+ or Tb 3+ single doped sample shows an excellent thermal property, but when the Ce 3+ and Tb 3+ are co-doped into the host, the thermal property of sample seriously degenerates. This result indicates that the change of temperature can affect the energy transfer between Ce 3+ and Tb 3+ strongly and based on the configurational coordinate diagram, this phenomenon is explained reasonably. [ABSTRACT FROM AUTHOR]