An in-depth study on physical properties of facilely synthesized Dy@CdS NPs through microwave route for optoelectronic technology

Structural analysis of Dy@CdS quantum dots (QDs) were investigated by the XRD and TEM/HRTEM. The particle size of Dy@CdS QDs was varies from 7.3 +/- 0.8 to 6.6 +/- 0.08 nm for 0.3% and 1.2% of Dy contents respectively. The vibrational spectra of pristine and Dy@CdS QDs exhibit the longitudinal phonon modes at 293 and 587 cm(-1). Optical band gap of 2.5 eV was optimized at 0.6% Dy doped CdS sample and found to be decreased on further increasing the Dy3+ content from 0.9 to 1.2%. The peaks at 414 and 466 nm are attributed to excitonic and trapped emission in the photoluminescence (PL) spectra of Dy@CdS samples respectively. The red shifts in PL spectra were observed for Dy3+ content more than 0.6% in Dy@CdS QDs. The frequency dependent char-acteristics of dielectric constant, dielectric loss, tangent and ac conductivity of Dy@CdS QDs were investigated at 300 K. It was founded that lower frequency range is dominated by the space charge polarization whereas orientational polarization is dominant at higher frequencies by increasing the dielectric constant. The variation of ac electrical conductivity was carried out linearly in the frequency range 15 kHz-10 MHz. The easy way of repeatability, tenability and scalability of Dy@CdS QDs are attributed for optoelectronics application.