Optical ratiometric probes based on photoluminescent core–shell structured carbon dots@silica for temperature sensing

Accurate temperature measurements with high spatial resolution are crucial in the biomedical field, demanding innovative nanoscale thermometers with advanced properties. In this study, core–shell carbon dots (CDs@SiO 2 ), supported with fluorescein and manganese phosphate flakes (Mn 3 (PO 4 ) 2 ), are utilized as dispersible ratiometric temperature sensors. These materials exhibit dual emission in the visible spectral range and have previously demonstrated effectiveness as fluorescent thermometers. However, the strong optical properties and morphology of CDs require precise control over temperature‐dependent fluorescent spectra in the range of 293–343 K, making them suitable for biological systems. The ratiometric response of the two integrated emission bands from CDs@SiO 2 @Fluo and CDs@SiO 2 @MnP decreases monotonically with increasing temperature, indicating high relative sensitivity and minimal temperature error at room temperature. This underscores the effectiveness of the functionalization strategy and highlights the potential of core–shell structures for future biomedical applications.