Optical and electrical properties of quantum composite of polyvinyl alcohol matrix with CdSe quantum dots

Abstract

CdSe quantum dots (QDs) were prepared by a sim- ple green route with CdSO4 and Na2SeSO3 in aqueous solu- tion. The as-prepared citrate-capped CdSe QDs were charac- terized by XRD and TEM. Single-phase cubic zinc blende structure was confirmed with uniform size and highly crystal- lized QDs of CdSe. Composite based on the decoration of polyvinyl alcohol (PVA) matrix with CdSe QDs was fabricat- ed by the solution casting process. UV-vis absorption spectra confirmed the formation of composites with a refractive index which was enhanced with CdSe weight fraction wt%. Photoluminescence properties of CdSe@PVA composites at differentCdSe QDweightfractions (wt%) wererecorded. The emission colors were controlled by CdSe wt% and tuned with its particle size. The a.c. electrical conductivity was measured at temperatures from 300 to 493 K and at frequencies from 50 to 100 kHz. The dielectric constant was enhanced after inserting CdSe QDs into PVA matrix. The a.c. electrical con- ductivityresults showedthatPVA andCdSe@PVA composite films follow the overlap large polarons (OLP) model. Also, the activation energy (Ea) decreased with the presence of CdSe in PVA polymer relative to pure PVA.