Simultaneous enhancement upconversion luminescence and photocatalytic properties of BiOBr:Yb3+, Er3+ nanosheets by optically inert ions doping

Lanthanide-doped upconversion (UC) materials are important in near-infrared (NIR) photocatalytic field because they can harvest NIR photons and then emit high-energy UV and visible light via the UC process. However, these materials still exhibit low UC luminescence efficiency, which strongly limits their practical applications. Herein, we report UC luminescence enhancement in BiOBr: Yb 3+ , Er 3+ (BYE) nanosheets by doping Li + and Zn 2+ and the elucidation of the enhancement mechanism. The XRD and Rietveld refinement results showed that the doping improved the crystallinity of the samples, with the effect of codoping being more pronounced than that of single doping. Under 980-nm laser excitation, the red emission of the Li + -Zn 2+ -codoped BYE sample increased drastically by 2.5, 4.3, and 5.3 times than that of the Li + -doped BYE, Zn 2+ -doped BYE, and BYE samples, respectively. The luminescence enhancement could be ascribed to the reduction of the crystal site symmetry and the improvement of the crystallinity upon Li + and Zn 2+ doping. Moreover, photocatalytic experiments showed that Li + and Zn 2+ doped BYE exhibited better photocatalytic performance than BYE, thus paving the way toward achieving enhanced UC luminescence efficiency.