Ratiometric Thermometry Using Thermochromic Tb³⁺:Mn⁴⁺:Na₄Mg(WO₄)₃ Phosphors

Abstract

The utility of Tb 3+ :Mn 4+ :Na 4 Mg(WO 4 ) 3 phosphors as ratiometric luminescent thermometers in the 200−450 K temperature range is demonstrated. Targeted substitution of Tb 3+ for Na + and Mn 4+ for Mg 2+ yields phosphors of formula Na 4−12x Tb 4x Mg 1−2y Mn y (WO 4 ) 3 . UV excitation of the Na 4 Mg(WO 4 ) 3 host results in green emission from terbium (544 nm) and red emission from manganese (682 nm). Differential thermal quenching of these emissions renders Na 3.976 Tb 0.008 Mg 0.990 Mn 0.005 (WO 4 ) 3 thermochromic between 78 and 450 K, with an orange-to-green color change that is particularly noticeable above 200 K. As a result, this phosphor serves as a ratiometric and colorimetric thermometer between 200 and 450 K. Quantitative assessment of its performance yields a maximum relative sensitivity of 2.5 × 10 −2 K −1 at 375 K, along with a resolution of 0.5 K and a repeatability of 98%. These findings highlight the versatility of Na 4 Mg(WO 4 ) 3 as a platform to realize luminescent thermometers via targeted aliovalent substitutions.

Suppressed Self‐Reduction of Manganese in Mg2SnO4 via Li+ Incorporation with Polychromatic Luminescence for Versatile Applications

“…Thereby, the sensor sensitivity of y L‐MSO:Mn phosphors can be simultaneously regulated by changing excitation wavelength and doping concentration. Additionally, compared with those of previously reported optical temperature sensors based on luminescent materials, [ 18,24,38–49 ] the S r value of studied compounds is satisfactory, as depicted in Figure 5g, illustrating that the y L‐MSO:Mn phosphors are promising luminescent candidates for optical thermometry.…”

XANES analysis of phosphate glasses melted with Tb4O7 and SnO: evaluating the impact of valence states on structural, thermal, and luminescent properties

“…30 The 1-5SnTb glasses on the other hand are lacking the Tb 4+ peak and exhibit a single peak harmonizing with the occurrence of terbium as Tb 3+ ions. 31 This was noticed even at the lowest tin content in the 1SnTb glass exhibiting a peak in Fig. 4 around 7518.3 eV.…”

Designing dual-emission phosphors for temperature warning indication and dual-mode luminescence thermometry

“…Table 2 summarizes the S R of some recently studied RE 3+ /TM 4+ doped phosphors. 20,23,29,46–55 It is worth noting that the obtained relative sensitivity could be promised for luminescence thermometry.…”