Facile synthesis, structural, electrical and dielectric properties of CdSe/CdS core-shell quantum dots

Quantum dots (QDs) consisting of CdSe (core) with CdS (shell) were synthesized by an organometallic precursors method. The average sizes of CdSe/CdS core-shell quantum dots were estimated from X-ray diffraction by Debye-Scherer formula and compared with high resolution electron microscopy (HRTEM). The shape of CdSe/CdS QDs was nearly spherical and reveals that the CdS shell almost fully cover the CdSe core with thickness of 0.7 nm. DC and AC conductivity, dielectric loss, and dielectric constant of CdSe/CdS core-shell QDs were described. The electrical properties of nanoparticles pellet of CdSe/CdS core-shell QDs were studied over a temperature range from 323 to 453 K. The values of dc activation energy and the pre-exponential were determined. The ac conductivity was found to increase with the increase of both the temperature and the frequency, and follows the power low. The frequency exponent s was found to decrease with the increase of temperature. The correlated barrier hopping (CBH) model was found to be applying to the ac conductivity data. The observed properties of the prepared CdSe/CdS core-shell QDs demonstrated the capabilities of these nanomaterials as a good candidate in the optoelectronics and photonics devices.