High-efficient and reversible temperature sensor fabricated from highly luminescent CdTe/ZnS-SiO2 nanocomposites for rolling bearings

Abstract CdTe quantum dots (QDs) have broad application prospects in the field of thermal monitoring of bearing rotating components owing to the linear temperature dependence of their photoluminescence. However, their practical application can be limited by irreversible thermal stability. In this work, we synthesized CdTe/ZnS-SiO2 nanocomposites by a reversed-phase microemulsion method based on CdTe QDs prepared in an aqueous phase. The structure and optical performance of as-synthesized CdTe/ZnS-SiO2 were characterized. CdTe/ZnS-SiO2 shows high photoluminescence, outstanding reversible thermal stability, and low biotoxicity because of the elimination of surface defects on the QDs by the ZnS layer and inorganic protection by the SiO2 layer. The photoluminescence spectra of CdTe/ZnS-SiO2 show linear relationship and reversible thermal stability during heating and cooling cycle processes from room temperature to 80 °C, which facilitates their practical application as temperature sensors. The highly efficient and reversible temperature sensor fabricated from highly luminescent CdTe/ZnS-SiO2 nanocomposites has significant application value in the thermal monitoring field, especially for high-speed bearings under various conditions.