Elucidating structural, optical, and fluorescence intensity ratio-based temperature-sensitive luminescence aspects of Pr3⁺-activated Ca2Al2SiO7 phosphors

Abstract In this study, we investigated the structural, optical, concentration, and temperature-sensitive luminescence properties of praseodymium (Pr 3 ⁺)-doped Ca 2 Al 2 SiO 7 phosphors synthesised via a urea-assisted combustion method. Rietveld refinement and XRD analyses confirmed the formation of a tetragonal phase with a P͞ 42 1 m space group. The energy band gap was 4.430 $$\pm$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>±</mml:mo> </mml:math> 0.124 eV, and DRS analysis confirmed different transitions of Pr 3+ ions. The concentration dependency of the emission was explored using room-temperature PL, where the optimum performance was observed for a dopant concentration of 4 mol%. The UVC emission of Pr 3+ ions is associated with the 4f 1 5d 1 → 3 H J and 3 F 2 energy levels, and the decay lifetime is in the range of 7.3–8 μs. The emission intensity decreased with increasing temperature, indicating temperature quenching. A high quenching temperature (412 K) and a high activation energy of 0.258 $$\pm$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>±</mml:mo> </mml:math> 0.016 eV were obtained for the CASO-4 Pr phosphor, confirming its exceptional thermal stability. The applicability in the field of temperature sensing was explored based on the FIR approach, estimating S A as 2.562 $$\times$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>×</mml:mo> </mml:math> 10 –4 K −1 and S R as 0.02% K −1 at 473 K.