Multifunctional optical thermometry based on the transition metal ions doped down-conversion Gd2ZnTiO6: Bi3+, Mn4+ phosphors

Highlights: • A novel thermometer Gd₂ZnTiO₆: Bi³⁺, Mn⁴⁺ is designed with high sensitivity. • The energy transfer process from Bi³⁺ to Mn⁴⁺ is realized in Gd₂ZnTiO₆. • The luminescence of phosphors is strong enough to make LED chips. • The luminescence of phosphors can be well absorbed by photosynthetic pigments. Nowadays, how to improve the accuracy of the temperature sensors has become a common concern of researchers. For this purpose, dual-emitting phosphors have been proposed as a novel optical thermometer because the two discriminate emission centers can avoid the error caused by spectral overlap. Herein, a new ratio-metric luminescent thermometer Gd₂ZnTiO₆(GZTO):Bi³⁺, Mn⁴⁺ is designed, which exhibits both red and blue luminescence under 375 nm excitation. Based on the different thermal sensitivity of Mn⁴⁺ and Bi³⁺ ions and the energy transfer from Bi³⁺ to Mn⁴⁺ ions, the luminescent thermometer reveals excellent thermal sensitivity (S_r = 2.4% K⁻¹, S_a = 16.8%K⁻¹) and a wide temperature measurement range (313–473 K). Both of them are superior to the most reported materials. In addition, the luminescence intensity of two ions matches the light absorption bands of photosynthetic pigment well, which indicates that GZTO: Bi³⁺, Mn⁴⁺ phosphors also have a great prospect as a plant growth lamp.