High sensitivity ratiometric fluorescence temperature sensing using the microencapsulation of CsPbBr3 and K2SiF6:Mn4+ phosphor

A dual emission sensing film has been prepared for colorimetric temperature sensing using CsPbBr3 perovskite nanocrystals (CsPbBr3 NCs) and manganese doped potassium fluorosilicate (K2SiF6:Mn4+, KSF) encapsulated in polystyrene by a microencapsulation strategy. The CsPbBr3-KSF-PS film shows good temperature sensing response from 30 °C to 70 °C, with a relative temperature sensitivity (Sr) up to 10.31% °C−1 at 45 °C. Meanwhile, the film maintains more than 95% intensity after 6 heating-cooling cycles and keeps its fluorescence characteristics after 3 months. The film can be used to monitor temperature change by naked eye under a UV lamp. In particular, the temperature discoloration point of the sensing film can be controlled by the ratio change of CsPbBr3:KSF to expand its applications. The study of the CsPbBr3-KSF-PS sensing mechanism in this work is helpful to provide effective strategies for the design of reliable, high sensitivity and stable temperature sensing system using CsPbBr3 NCs.