Enhancement of the sensitivity of a quantum dot-based fiber optic temperature sensor using the sol–gel technique

A hydrolyzed and polymerized mixture of 3-glycidoxypropyl trimethoxysilane (GPTMS) and 3-aminopropyl trimethoxysilane (APTMS) was used as a carrier for CdSe/ZnS quantum dots (QDs) used in fabricating a fiber optic temperature sensor (FOTS). The combination of the carboxyl and amine groups of the QDs and APTMS, respectively, prevented the QDs from forming large aggregates and enabled the desired distributions of QDs to be established. The sol–gel consisting of the mixture of GPTMS and APTMS created a flexible carrier for the QDs, thereby improving their thermal shock resistance and enabling them to be used for temperature sensing in the temperature range of 0–100 °C. The linear detection range of the sensor (QD-FOTS) was between 0 and 100 °C with a relative standard deviation of less than 10%.