Effect of temperature on the morphological, optical, and photocatalytic properties of CdS quantum dots

We report the effect of thermolysis temperature on the morphological and optical properties of cadmium sulphide quantum dots prepared from bis((2-morpholinoethyl) carbamodithioate)Cd(II) precursor at 120, 180 and 240 ?. Powder XRD analysis revealed hexagonal crystalline phase for the CdS quantum dots. TEM images revealed almost spherical monodispersed particles, with size ranges of 3.2-4.9 nm for HDA-CdS1 prepared at 120 degrees C, while for HDA-CdS prepared at 180 degrees C particle sizes increased to 4.0-5.9 nm and 5.4-11.2 nm for HDA-CdS3 prepared at 240 degrees C. The results indicate thermolysis temperature influences the particle sizes and subsequently its use as photocatalyst. The band gaps were found to be 2.04 eV for HDA-CdS1, 2.01 eV for HDA-CdS2, and 2.07 eV for HDA-CdS3. The electrochemical properties of the HDA-CdS quantum dots were studied using cyclic voltammetry and calculated electrochemical band gaps were found to be 2.19 eV for HDA-CdS1, 2.15 eV for HDA-CdS2, and 2.06 eV for HDA-CdS3 which is close to the optical bandgap. The photocatalytic degradation of methylene blue by the CdS quantum dots showed degradation efficiency of 76% for HDA-CdS1, 47% for HDA-CdS2, and 61% for HDA-CdS3.

Automated summary

The study investigated the effect of thermolysis temperature on the morphological and optical properties of cadmium sulphide quantum dots, showing that temperature influences particle size and photocatalytic degradation efficiency. The analysis also revealed band gaps and electrochemical properties of the quantum dots, emphasizing the importance of temperature control in synthesis processes.