The size dependent thermal diffusivity of water soluble CdTe quantum dots using dual beam thermal lens spectroscopy

摘要

Size dependent thermal diffusivity of CdTe colloidal quantum dots samples has been studied using dual beam thermal lens spectroscopy. The thermal diffusivity values of the colloidal solution of CdTe quantum dots synthesized in water were found to be less than that of pure water (1.4 x 10(-7) m(2)/s) varying from 0.63 x 10(-7) m(2)/s to 0.15 x 10(-7) m(2)/s. The samples with this kind of very low value of thermal diffusivity can be good thermal insulators. To the best of our knowledge there are no reports on the study of thermal diffusivity of water soluble CdTe quantum dots. The non-radiative relaxation mechanism due to defect states, Brownian motion, capping agent etc. play major roles in controlling the thermal diffusivity of the nano-colloidal sample. The thermal diffusivity is found to be in inverse correlation with the emission intensity.