Rational design of Ca3HfSi2O9:Ce3+, Tb3+ dual-mode luminescence thermometer: uniting high sensitivity, outstanding signal resolution and detectable emission

The continuous progress in the development of luminescence thermometers highlights the importance of achieving high sensitivity, excellent signal resolution, and detectable emission. To tackle these challenges, the dual-emitting luminescence thermometer Ca₃HfSi₂O₉:Ce³⁺, Tb³⁺ was successfully designed and synthesized through a systematic approach. The crystal structure, electronic structure, luminescence properties, and thermoluminescence behavior of Ca₃HfSi₂O₉ singly doped with Ce³⁺ or Tb³⁺, as well as co-doped with both Ce³⁺ and Tb³⁺, were systematically investigated. Ca₃HfSi₂O₉:Ce³⁺, Tb³⁺ achieves exceptional signal resolution by leveraging the substantial energy gap (>4364 cm⁻¹) between the blue light emission of Ce³⁺ and the green light emission of Tb³⁺. A high relative sensitivity ranging from 1.2 %@298 K to 0.2 %@473 K is attained by exploiting the distinct temperature responses of Ce³⁺ and Tb³⁺. Additionally, the weak absorption of Tb³⁺ is compensated for through the sensitization effect of Ce³⁺ on Tb³⁺, enabling detectable emissions under high-temperature conditions. To demonstrate its practical applicability, the luminescence thermometer was encapsulated with epoxy resin to simulate chip temperature detection, achieving a temperature error of less than 1.5 % at 448 K.