Anomalous increase in luminous intensity in Ba2+ ion-doped negative thermal expansion material Sc2W3O12: Er3+/Yb3+

The thermal quenching effect of photoluminescent materials greatly limits their practical applications in bioimaging, sensing, radiation detection, and photovoltaic devices. In this paper, the upconversion luminescence (UCL) of Sc 2 W 3 O 12 :Er 3+ /Yb 3+ was significantly improved by doping Ba 2+ ions. The study identifies that the optimal doping concentration of Ba 2+ ions within the negative thermal expansion (NTE) phosphors Sc 2 W 3 O 12 : Er 3+ /Yb 3+ is 0.03 mol, the green and red light intensities of Sc 2 W 3 O 12 : Er 3+ /Yb 3+ /Ba 2+ phosphor were increased by 32.76 times and 23.06 times. When the temperature rises from 298 K to 523 K, the NTE effect causes an abnormally increased luminous intensity. Utilizing fluorescence intensity ratio (FIR) technology, the temperature sensing characteristics of the Sc 2 W 3 O 12 : 0.30 Yb 3+ , 0.02 Er 3+ , 0.03 Ba 2+ phosphor were further examined, achieving maximum relative and absolute sensitivities of 1.24 % K −1 and 1.97 % K −1 , respectively.