Dyes Encapsulated Nanoscale Metal–Organic Frameworks for Multimode Temperature Sensing with High Spatial Resolution
Wenqian Cao, Yuanjing Cui, Yu Yang, Guodong Qian
Abstract
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 (IFlu/I4-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 (Sm = 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.