Energy transfer-triggered multicolor emissions in Tb3+/Eu3+-coactivated Y2Mo3O12 negative thermal expansion microparticles for dual-channel tunable luminescent thermometers

Abstract

A rational control of the thermal quenching performance is crucial for achieving high quality luminescent thermometers. Herein, we report the synthesis of Tb³⁺/Yb³⁺-coactivated Y₂Mo₃O₁₂ (YMO) negative thermal expansion (NTE) microparticles with color-tunable emissions. Upon irradiation with 297 nm light, multicolor emissions (green-yellow-red) are observed in the developed samples which are trigged by efficient energy transfer (ET) from the Tb³⁺ to Eu³⁺ ions. Furthermore, according to the theoretical analysis based on the decay time and Inokuti–Hirayama model, the aforementioned ET mechanism is related to the dipole–quadrupole interaction. Owing to the NTE behaviors of the YMO host, ET between Tb³⁺ and Eu³⁺ ions is enhanced, causing them to possess diverse thermal quenching properties. Employing the fluorescence intensity ratio technology, the thermometric behaviors of the developed microparticles were investigated by discussing the temperature-dependent emission intensities of Tb³⁺ and Eu³⁺ ions. It is found that the sensitivities of the designed NTE microparticles are dependent on both the doping concentration and excitation wavelength. Additionally, the maximum absolute and relative sensitivities of YMO:Tb³⁺/0.10Eu³⁺ NTE microparticles are 0.017 K⁻¹ and 0.32% K⁻¹, respectively, at 363 K. These results reveal that the developed NTE microparticles have the capacity for contactless thermometry and their thermometric behaviors can be controlled by adjusting the doping content and excitation wavelength.