Photoluminescence quenching and conductivity enhancement of PVK induced by CdS quantum dots

In this work we studied the optical and transport properties of hybrid nanocomposites of CdS quantum dots (QDs) and poly(N-vinylcarbazole) (PVK) polymer. The CdS QDs were prepared by thermal decomposition (thermolysis) of a single source precursor, Cd bis-thiolate, in a high boiling solvent, octadecene (ODE). The optical characterization of the QDs has been carried out by UV–vis absorption and photoluminescence spectroscopy while the morphological properties have been investigated atomic force microscopy and transmission electron microscopy. The analyses have shown that CdS QDs of diameter below 6 nm can be synthesized by such route with good light emission in the UV range. The QDs have been dispersed in a poly(N-vinylcarbazole) (PVK) matrix to obtain a PVK:CdS nanocomposite layers. An increase of conductivity and a quenching of the photoluminescence have been observed when the nanocomposite layer was inserted in ITO/PVK:CdS/Al structures.

► Nanocomposites of PVK and CdS quantum dots with size of 5.9 nm have been prepared and studied in a diode structure ITO/PVK:CdS/Al.
► Transport measurements have shown a conductivity increase of two orders of magnitude of PVK when doped with CdS quantum dots.
► A photoluminescence quenching induced by interfacial charge transfer between PVK and CdS has been observed.