Enhanced upconversion luminescence and single-band red emission in -Ba2ScAlO5: Yb3+/Er3+phosphor through doping Cu2+

This study reports on a single-band red upconversion emission of Er3+ in a pure-phase & beta;-Ba2ScAlO5: Yb3+/Er3+ fluorescent powder by doping Cu2+. The optimum concentration of Cu2+ ions in & beta;-Ba2ScAlO5: Yb3+/Er3+ powder was 0.20. The red and green emission intensity of & beta;-Ba2ScAlO5: Yb3+/Er3+ sample with optimum concentration of Cu2+ ions increased by 19.1 and 3.6 times, respectively, relative to the & beta;-Ba2ScAlO5:Yb3+/Er3+ material lacking Cu2+ ions. The red-green integral intensity ratio of the & beta;-Ba2ScAlO5:Yb3+/Er3+/Cu2+ phosphor reached 141.9. The potential upconversion luminescence (UCL) mechanism was explored by analyzing the down-shift luminescence (DS) spectra, upconversion luminescence spectra, and upconversion fluorescence lifetime decay curves of Yb3+/Er3+/Cu2+ triple-doped & beta;-Ba2ScAlO5. Enhanced red emission and green upconversion emission are achieved by energy transfer between defect band by the oxygen vacancy and Er3+ energy levels. This study's findings establish the foundation for developing novel phosphors with single UC red light emission, which has potential applications in illumination displays, optical thermometry, and biomedicine.