Bi3+ photoluminescence in Y1-xBixCa3(GaO)3(BO3)4 and energy transfer to Eu3+ and Tb3+ in co-doped phosphors

Bi3+ possesses outer shell lone pair electrons, and, thus the so-involved photoluminescence (PL) is sensitive to the surrounding coordination. Besides, the similarity in the structural chemistry between Bi3+ and rare earth (RE) ions inspires us to investigate the Bi3+-PL performance in RE3+-containing hosts. Herein, Y1-xBixCa3(GaO)(3)(BO3)(4) (0.01 <= x <= 0.15) compounds were prepared by a high temperature solid state reaction method. The successful cationic doping and phase purity were confirmed by powder X-ray diffraction analysis. This series of phosphors exhibit the very strong absorption of Bi3+ 1S0 -> P-3(1) at 272 nm along with the intense blue emission with a maximum at 399 nm and a full width at half maximum (FWHM) of 59 nm. They retained 78.86% of the emission intensity at 150 degrees C, with reference to that at room temperature. Moreover, Bi3+ could also behave as a sensitizer to enhance the emission efficiency of RE3+ and thus to realize color-tunable phosphors. The energy transfer was proved in the co-doped phosphors Y0.95-yBi0.05EuyCa3(GaO)(3)(BO3)(4) (0.05 <= y <= 0.6) and Y0.95-zBi0.05TbzCa3(GaO)(3)(BO3)(4) (0.05 <= z <= 0.6), and color-tunable emissions from blue to red, or from blue to green were realized in these two series of phosphors.

Automated summary

A series of Bi3+-doped phosphors were synthesized by a high temperature solid state reaction method, showing that Bi3+ can act as a sensitizer to enhance the emission efficiency of rare earth ions, leading to color-tunable emissions. Energy transfer was confirmed in co-doped phosphors, resulting in color-tunable emissions from blue to red, or from blue to green.