The effect of solvent dependent local field factor in the optical properties of CdTe quantum dots

Abstract

CdTe quantum dots (QDs) are synthesized at room temperature in aqueous solvents of different dielectric constants and characterized using optical spectroscopy. Absorption spectra of the QDs obtained is used to calculate the size dependent dielectric function of the QDs using Kramers–Kronig relation and iterative matrix inversion method. Effect of solvent dielectric constant on optical properties of QDs is studied theoretically using Maxwell–Garnett effective medium theory. Direct correlation between absorption intensity and solvent dielectric constant is explained on the basis of decreasing local field factor of the solvents. Emission rates of QDs is also found to have dependence on the dielectric constant of the solvent. Spontaneous emission rates of QDs in Ionic liquid environment is studied theoretically using Maxwell–Garnett effective medium theory. Our results show that variation in dielectric constant of Ionic liquids have a significant impact on spontaneous emission properties of the QDs.