In situ growth of well-dispersed CdS nanocrystals in semiconducting polymers

Abstract

A straight synthetic route to fabricate hybrid nanocomposite films of well-dispersed CdS nanocrystals (NCs) in poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) is reported. A soluble cadmium complex [Cd(SBz)2]2·MI, obtained by incorporating a Lewis base (1-methylimidazole, MI) on the cadmium bis(benzyl)thiol, is used as starting reagent in an in situ thermolytic process. CdS NCs with spherical shape nucleate and grow well below 200°C in a relatively short time (30 min). Photoluminescence spectroscopy measurements performed on CdS/MEH-PPV nanocomposites show that CdS photoluminescence peaks are totally quenched inside MEH-PPV, if compared to CdS/PMMA nanocomposites, as expected due to overlapping of the polymer absorption and CdS emission spectra. The CdS NCs are well-dispersed in size and homogeneously distributed within MEH-PPV matrix as proved by transmission electron microscopy. Nanocomposites with different precursor/polymer weight ratios were prepared in the range from 1:4 to 4:1. Highly dense materials, without NCs clustering, were obtained for a weight/weight ratio of 2:3 between precursor and polymer, making these nanocomposites particularly suitable for optoelectronic and solar energy conversion applications.

The effect of alumina content on the structural properties of ZrO2-Al2O3 unstabilized composite nanopowders

“…CO +2 -doped CdS/ polyvinyl pyrolidone composite was synthesized by chemical precipitation method [44]. Spin-coating technique was used to prepare thin films of CdS/poly[2-methoxy-5-(2′ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) nanocomposite [45]. Several other CdS/polymer nano composites such as CdS/polyamidoamine dendrimer [46], CdS/ poly[4-(n-acryloyloxyalkoxy)benzoic acid] [47], and many more [48,49] were also investigated.…”

Sodium-alginate biopolymer as a template for the synthesis of nontoxic red emitting Mn2+-doped CdS nanoparticles

“…17 This polysaccharide was already used as an environment for controlled growth of II-VI semiconductors, 18 Co, Ni, and CoNi nanoparticles, 19 iron oxide nanostructures 20 as well as antimicrobial ZnO nanoparticles 21,22 and hybrid ZnO/Ag nanocubes. 23 However, to the best of our knowledge, alginates were not used for the preparation of diluted magnetic semiconductor nanoparticles such as the CdS:Mn described in the present work. In this study, we used an in situ chemical synthesis for the preparation of CdS:Mnalginate nanocomposites in which the nanoparticles were formed directly within the biopolymer matrix.…”

Direct Synthesis of P3Ht/Cds Nanocomposites with End-Functionalized P3Ht as the Template

“…MEH-PPV/ PbS composites were prepared by Watt et al 9 via directly growing PbS nanocrystals in MEH-PPV solution without surfactants; they showed that the polymer chains could act as templates to stabilize nanocrystal growth in solution. The growth of well-dispersed CdS nanocrystals in MEH-PPV was reported by Laera et al 16 via a soluble cadmium complex [Cd(SBz) 2 ] 2 •MI used as starting reagent in an in-situ thermolytic process. To further enhance the photoelectric conversion efficiency of the product, we synthesized a phosphonic ester end-functionalized P3HT, which could afford more intimate contact with the nanocomposites by ionic bonds, which is a powerful chemical bond, between Cd 2+ ions and phosphate.…”

“…However, the presence of surfactants severely reduces the device efficiency by impeding the transfer of charge between nanocrystals and polymer, as well as the transport of electrons between adjacent nanocrystals 15 . Recently, there have been some reports 4,9,16 of the direct synthesis of semiconductor nanocrystal/ conjugated polymer composites with the connection of covalent bond. By such a new approach, the negative effects of the surfactants to charge transfer are no need to consider.…”