Radial mesoporous silica supported Eu3+-functionalized carbon dots for ratiometric tetracycline detection and their polyvinylidene fluoride hybrid film for temperature sensing

A radial mesoporous silica (mSiO 2 ) supported Eu 3+ -functionalized carbon dots (CDs) nanocomposite (mSiO 2 -CDs-Eu) was successfully prepared using citric acid as CD precursors, showing specific ratiometric tetracycline (TC) fluorescence sensing behavior. The blue fluorescence of CDs is quenched by the internal filtering effect with TC, and the red fluorescence intensity of Eu 3+ ions is improved on account of an antenna effect. The self-calibrated ratiometric fluorescence sensing of TC by mSiO 2 -CDs-Eu showed a minimum detection limit of 30 nM. In addition, a mSiO 2 -CDs-Eu hybridized polyvinylidene fluoride (PVDF) film was developed for optical temperature sensing with a high-temperature sensitivity of 1.69% °C −1 in the physiological temperature range of 25–45°C and a temperature resolution greater than 0.04°C. This work demonstrates a feasible way in fabricating dual-functional mSiO 2 -CDs-Eu nanocomposite with optical ratiometric sensing properties toward both TC and temperature changes, opening its promising applicability for food security and temperature monitoring.