Synthesis, Morphology, and Optical Properties of Au/CdS Hybrid Nanocomposites Stabilized by Branched Polymer Matrices

V A Chumachenko,A P Naumenko,I S Bondarchuk,N V Kutsevol,O A Yeshchenko

doi:10.1155/2016/1439437

V A Chumachenko, A P Naumenko + Show 3 more

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https://doi.org/10.1155/2016/1439437

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Abstract

Metal/semiconductor (Au/CdS) nanocomposites were synthesized in the solution of branched D-g-PAA polymer. TEM and DLS of Au/CdS/D-g-PAA nanocomposites revealed complicated nanocomposite structure consisting of the Au nanoparticles (NPs) of 6 nm in size surrounded by small CdS NPs with size of 3 nm. These nanocomposites formed the aggregates-clusters with average size of 50–800 nm. Absorption spectra of Au/CdS nanocomposites consist of the bands of excitons in CdS NPs and surface plasmons in Au ones. The surface plasmon band of gold NPs is red shifted and broadened in Au/CdS/D-g-PAA nanocomposites comparing to the one of Au NPs in Au/D-g-PAA proving the fact of close location of CdS and Au NPs in the synthesized Au/CdS/D-g-PAA nanocomposites. The PL spectra of Au/CdS nanocomposites originate from the radiative transitions in excitons in CdS NPs. The 4-fold increase of intensity of free exciton PL is observed for CdS NPs in Au/CdS/D-g-PAA comparing to CdS ones in CdS/D-g-PAA that is due to PL enhancement by local field of surface plasmons of Au NPs. Also, the 12-fold decrease of intensity of localized exciton PL is observed for CdS NPs in Au/CdS/D-g-PAA comparing to CdS ones in CdS/D-g-PAA. Most probably, it is due to passivation of the surface of CdS NPs carried out by the Au ones.

Highlights

Semiconductor nanoparticles are of great interest for both fundamental research and industrial development because of their exciting utilization in the areas of light-emitting diodes, electroluminescent devices, lasers, hydrogen producing catalyst, biological labeling, and immune diagnosis [1,2,3,4,5,6,7]
In the first stage the Au NPs were synthesized by the chemical reduction of Au precursor (HAuCl4) dissolved in polymer aqueous solution at T = 25∘C in aqueous solutions of dextrangraft-polyacrylamide copolymer (D70-g-PAA5). 0.24 mL of
It can be concluded that Au/CdS nanocomposites are fabricated into the polymer molecule and form the clusters localized in limited macromolecule volume

Summary

Introduction

Semiconductor nanoparticles are of great interest for both fundamental research and industrial development because of their exciting utilization in the areas of light-emitting diodes, electroluminescent devices, lasers, hydrogen producing catalyst, biological labeling, and immune diagnosis [1,2,3,4,5,6,7]. In recent decades, there has been a huge interest in metal-based plasmonic nanostructures for applications in biosensing, nanophotonics, and enhanced light emission [8,9,10] This is due to the collective coherent excitations of the free electrons in nanosized metal, known as surface plasmon resonance (SPR). Journal of Nanomaterials of these nanostructures, for example, often exhibit interesting deviations from their individual components These optical effects include a shift in the surface plasmon resonance of noble metal NPs when combined or coated with other materials [26, 27] or changes in the PL intensity of semiconductor NPs which can be attributed to the overlap of the electronic structures of the different components [28]. The quenching of the luminescence of localized excitons in CdS NPs occurring due to possible passivation of the surface of CdS ones was observed

Experimental Details

Characterization

Results and Discussion

Conclusions