Dyes Encapsulated Nanoscale Metal–Organic Frameworks for Multimode Temperature Sensing with High Spatial Resolution

Luminescent nanothermometers working with high resolution and multiple optical signals are a powerful tool for complex analysis with high accuracy and selectivity. Herein, we describe a novel strategy, for the first time, by encapsulating two types of luminescent dyes (4-Mu and Flu) into the pores of a nanoscale metal–organic framework (MOF) ZIF-8 for multimode temperature sensing. When the temperature rises, the maximum emission wavelength (λmax) of dye 4-MU in ZIF-8⊃4-MU&Flu redshifts, and the emission ratio (I Flu/I 4‑MU) of Flu and 4-MU in ZIF-8⊃4-MU&Flu shows good linear response to temperature, which indicate the high sensitivity of the nanothermometer with multimode temperature readout (S m = 0.62% K–1 at 240 °C). Remarkably, the uniform nanoscale size distribution and good thermal stability of the nanosized MOF⊃dyes composites enable it to perform multimode temperature sensing with high spatial resolution, which is demonstrated by the temperature mapping. Therefore, this material shows a more-reliable temperature indication by utilizing the multiparameter readout and an excellent temperature distribution with high spatial resolution.