A new perspective on the significant enhancement mechanism of luminescence properties by the Ce ion valence states

This paper reveals a two-step reduction method for obtaining NaSr 4 (BO 3 ) 3 (NSBO):Ce series phosphors with better performance. XPS analysis confirms that the two-step reduction method achieves a higher proportion of trivalent Ce ions (in Ce 3 + /Ce 4 + ) with 54.38%, resulting in better photoluminescence and thermoluminescence properties compared to the one-step reduction method (41.21% and 28.11%). The sample exhibits better thermal stability, with a thermal quenching activation energy of 0.19595 eV. Ce 3 + doping creates deeper traps, thus enhancing photoluminescence intensity and generating more and deeper traps, which may be attributed to oxygen vacancies ( V O ) and strontium vacancies ( V Sr ). The NSBO: 0.07Ce 3 + sample exhibits better thermal stability 52% at 473K, with a thermal quenching activation energy of 0.19595 eV. The sample displays a lower correlated color temperature ( CCT ) of 1778 K and a higher color purity ( CP ) of 98.64%. The concentration quenching ( CQ ) mechanism is dipole-quadrupole (