Down-conversion luminescence and thermometric properties of novel orange-red Bi2Mo3O12:Pr3+ phosphors

Bi 2 Mo 3 O 12 : Pr 3+ phosphors have been successfully synthesized through a one-step solid-state reaction method. The effects of Pr 3+ concentration on lattice constants and optical properties were also studied. XRD patterns showed well-crystallized monoclinic structures for the prepared Bi 2 Mo 3 O 12 and Bi 2 Mo 3 O 12 : Pr 3+ samples. The UV–visible diffuse reflectance spectra indicated strong absorption in the ultraviolet region. Excitation spectra demonstrated that the Bi 2 Mo 3 O 12 : Pr 3+ could be efficiently excited under UV light in the 250–430 nm range and blue light at 450 nm. By varying the excitation wavelength, the emission color could be tuned from orange-red to red region. The strongest emission peak is located at around 597 nm, which is attributed to the 1 D 2 → 3 H 4 transition of Pr 3+ . An optical thermometer based on fluorescence intensity ratio (FIR) shows a high sensitivity of S r  = 2.02 % K −1 , indicating the developed materials have potential applications in the optical temperature sensing field.