NIR emitting terephthalates (Sm Dy Gd1--)2(tph)3(H2O)4 for luminescence thermometry in the physiological range

The first luminescence thermometer based on coordination compound of samarium and dysprosium is reported. High luminescence intensity and high signal resolution are reached thanks to the concentration quenching reduction due to the use of the trimetallic complexes of Sm-Dy-Gd. The best thermometric properties in a wide temperature range among the studied systems are demonstrated by (Sm0.2Dy0.15Gd0.65)2(tph)3(H2O)4. The sensitivity reaches 0.5%/K in visible range and 1.2%/K in NIR range at low temperatures and 0.5%/K and 0.8%/K in physiological range.