Lanthanide coordination compounds contining multiple lanthanides are the most promising candidate materials for luminescent thermometry. Sensing elevated temperatures requires highly stable complexes and matrices, such as those of thermally stable polymers. However, most high-temperature polymers are not optically inert, and this can affect their thermometric properties, including decreasing their intensity and sensitivity. In the present paper, the proper selection of the combination of a matrix and two emitters allowed us to obtain a highly sensitive and highly emissive luminescent thermometry material, 1{5[Tb(Bz)3Phen]2+1[Eu(Bz)3Phen]2}:4PI4050, based on terbium and europium complexes in poly(ethylene glycol) diacrylate (PI4050), which is suitable for the detection of temperatures up to 200 °C.
