Single‐Band Ratiometric Luminescent Thermometry Using Pr3+ Ions Emitting in Yellow and Red Spectral Ranges

The possibility of using Pr 3+ ions to develop multicolor‐emission‐based luminescence thermometry in a single‐band‐ratiometric configuration is investigated for the first time. The thermally induced decrease in intensities of 3 P 0 → 3 F 2 and 1 D 2 → 3 H 4 emission bands is demonstrated using the excitation matching the ground‐state absorption, and an inverse relation is obtained using the optical excitation matching the excited‐state absorption. The strategy of modulation of the thermometric properties of the Pr 3+ ‐based red‐ and yellow‐emitting single‐band ratiometric (SBR) luminescent thermometers by the activation of the cross‐relaxation (CR) phenomenon promoted by the dopant concentration is elaborated. Contrary to expectations, the { 3 P 0 , 3 H 4 } ↔ { 1 D 2 , 3 H 6 } CR process is shown to cause the high and low dopant concentrations to be optimal for highly sensitive SBR luminescent thermometers operating in the red and yellow spectral ranges, respectively. In both cases, high relative sensitivities of the temperature readout are obtained. These results make Pr 3+ ions promising candidates for a SBR thermometry approach.