Hybrid Mn(II)‐Based Halides Gel Films for Fluorescence Lifetime‐Based Temperature Sensing

Sensing temperature using fluorescent materials by monitoring alterations in temperature-dependent luminescence characteristics is of great importance for various application fields, including modern industry, scientific research, and daily life. However, there are two main concerns on optical thermometry, and one is the low sensitivity, particularly at elevated temperatures, failing to meet precise measurement demands; another issue is how we can apply the thermometry in in situ environments. Herein, we design and report a hybrid manganese-based halide thermometry exhibiting a relative sensitivity (S_r) of 26.368% K^{- 1} at 463 K. We further propose a facile synthesis method for photopolymerizable hydrogel films containing the crystallized manganese-based halide thermometry, maintaining the same luminescence and sensing property. The luminescent gel film is applied to chip-based temperature sensing, demonstrating highly accurate performances as smart sensors and flexible electronic materials. This work opens up a new route to design luminescent metal halide thermometry to enrich the library of temperature sensing. Moreover, the luminescent gel film as optical thermometry can be applied in situ from micro-electronics to large-scale industrial systems, supplying new possibilities for advanced sensing and spectroscopy studies.