Enhancing upconversion luminescence intensity of BiTa 7 O 19 :Er 3+ /Yb 3+ /Mo 4+ by doping Sc 3+ or Sb

Abstract Based on the previous optimal concentration of Er 3+ /Yb 3+ /Mo 4+ co‐doped BiTa 7 O 19 (BTO) samples, Sc 3+ or Sb is planned to be doped into BTO:Er 3+ /Yb 3+ /Mo 4+ for further improving the upconversion luminescence (UCL) intensity under 980‐nm laser excitation. A series of BTO:Er 3+ /Yb 3+ /Mo 4+ /Sc 3+ and BTO:Er 3+ /Yb 3+ /Mo 4+ /Sb samples are prepared by high‐temperature solid‐phase sintering method. The microstructure and UCL properties are investigated by X‐ray diffraction, Raman, X‐ray photoelectron spectroscopy (XPS), diffuse reflection, and luminescence spectrum. The green UCL intensity of BTO:Er 3+ /Yb 3+ /Mo 4+ /Sb is little better than that of BTO:Er 3+ /Yb 3+ /Mo 4+ /Sc 3+ , which reaches 2.40 times than that of β‐NaYF 4 :Er 3+ /Yb 3+ . XPS results show that Sc is 3+, Mo is 4+, and Sb is 3+ and 5+. Raman spectra show that BTO:Er 3+ /Yb 3+ /Mo 4+ /Sb has lower phonon energy and more disorder than BTO:Er 3+ /Yb 3+ /Mo 4+ /Sc 3+ . The maximum relative temperature sensitivity is got as 0.01012 K −1 at 303 K based on luminescence intensity ratio technology. BTO:Er 3+ /Yb 3+ /Mo 4+ /Sb has outstanding pure green UCL intensity, which can be applied to luminescence display and temperature sensing.