Real‐Time Temperature Monitoring with Cr³⁺‐Based Hybrid Formate Perovskites: Insights into the Relation Between Chemical Composition and Thermometric Performance

Abstract Metal–organic frameworks (MOFs) exhibiting perovskite‐like structures have become a significant object of study due to their structural, phonon, and optical features. Temperature‐dependent luminescence is a valuable property within the context of luminescence thermometry. Herein, we report structural and spectroscopic studies of a series of [DMA]M^II_1‐xCr_x(HCOO)₃, where DMA = dimethylammonium cation, x = 0, 0.01, 0.03, and 0.05, while M^II = Zn²⁺, Mn²⁺, Mg²⁺, Co²⁺, and Ni²⁺. The influence of the metal type on crystal field strength (Dq/B) is determined with diffuse reflectance spectroscopy. Additionally, the estimation of the crystal field strength is performed with the analysis of the metal‐oxygen distance. Conducted Raman, IR, and XRD analysis provide information on the relationship between structural properties and chemical composition. To investigate the thermometric potential of obtained materials the temperature‐dependent luminescence measurements (80–300 K) are implemented. Obtained results show the extraordinary potential of hybrid compounds for luminescence thermometry (relative senitivity (S_r)up to 2.49%∙K⁻¹ at 160 K). The exemplary system based on luminescent thermometers for remote temperature measurements in dynamic systems has been additionally proposed. The presented results show a significant relationship between the surrounding temperature, chemical composition, and spectroscopic properties, allowing to design of a temperature sensing model for time‐resolved measurements.