Ceiling temperature and photothermalsensitivity of aqueous MSA-CdTe quantum dots thermometers

Ceiling temperature, photothermal sensitivity and size effects of aqueous mercaptosuccinic acid modified CdTe quantum dots (MSA-CdTe QDs) are determined from experimental measurements for temperature sensing applications. Measured data show that the ceiling temperature of MSA-CdTe prepared by the hydrothermal process is 60 °C, better than that of CdTe QDs modified by thioglycolic acid (TGA). Aqueous MSA-CdTe QDs exhibit a reversible PL spectral peak wavelength shift within the temperature range from room temperature up to the ceiling temperature 60 °C. With the size of the QDs increasing from 1.9 nm to 3.1 nm, the photothermal sensitivity remains unchanged and a stable linear correlation with a slope of 0.16 nm/ °C exists between the PL spectral peak wavelength position and the temperature. The morphology of QDs was examined under transmission electron microscopy (TEM). The measured emission photoluminescence data by QDs further show that the thermal sensitivity is independent of the size of the QDs for the size range studied. Theoretical analysis is presented to substantiate the experiment results.