Marta Kruszynska

Synthesis and Shape Control of CuInS2 Nanoparticles

Cu(2)S-CuInS(2) hybrid nanostructures as well as pure CuInS(2) (CIS) nanocrystals were synthesized by methods of colloidal chemistry. The structure, the shape and the composition of these nanomaterials were investigated with transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDX). By changing the reaction conditions, CuInS(2) nanorods with different aspect ratio, dimeric nanorods as well as hexagonal discs and P-shaped particles could be synthesized. Under our reaction conditions, CIS nanoparticles crystallize in the hexagonal wurtzite structure, as confirmed by Rietveld analysis of the X-ray diffraction patterns. The formation of Cu(2)S-CuInS(2) hybrid nanostructures turned out to be an essential intermediate step in the growth of CIS nanoparticles, the copper sulphide part of the hybrid material playing an important role in the shape control of the CIS nanocrystals. By a treatment of Cu(2)S-CuInS(2) with 1,10-phenanthroline, Cu(2)S parts of the hybrid nanostructures could be removed, and pure CIS nanoparticles with shapes not accessible with other methods can be obtained. Our synthetic procedure turned out to be suitable to synthesize also other compounds, like CuInS(2)-ZnS alloys, and to modify, in this way, the optical properties of the nanocrystals.

Size and shape control of colloidal copper(I) sulfide nanorods.

Many physical and chemical properties of semiconducting nanocrystals strongly depend on their spatial dimensions and crystallographic structure. For these reasons, achieving a high degree of size and shape control plays an important role with respect to their application potential. In this report we present a facile route for the direct colloidal synthesis of copper(I) sulfide nanorods. A high reactivity of the starting materials is essential to obtain nanorods. We achieve this by using a thiol that thermally decomposes easily and serves as the sulfur source. The thiol is mixed in a noncoordinating solvent, which acts as the reaction medium. Adjustment of the nucleation temperature makes it possible to tailor uniform nanorods with lengths from 10 to 100 nm. The nanorods are single crystalline, and the growth direction is shown to occur along the a-axis of djurleite. The growth process and character of the nanorods were investigated through UV-vis and NIR absorption spectroscopy, transmission electron microscopy, and powder X-ray diffraction measurements.

Influence of particle size in hybrid solar cells composed of CdSe nanocrystals and poly(3-hexylthiophene)

Inorganic semiconductor nanoparticles, such as CdSe quantum dots, are considered to be a promising alternative to fullerene derivates for application as electron acceptors in polymer-based bulk heterojunction solar cells. The main potential advantage is the strong light absorption of CdSe nanoparticles with a spectral bandwidth, which can even be tuned, due to the quantum size effect. However, the impact of the particle size on the performance of polymer/CdSe solar cells has remained largely unexplored so far. Therefore, the influence of particle size in hybrid solar cells using a blend of poly(3-hexylthiophene) (P3HT) and quasi-spherical CdSe nanoparticles on relevant cell parameters and the overall solar cell performance is systematically studied in the present work. As the most important result, an increase of the open-circuit voltage (VOC) can be found for smaller nanoparticles and can be explained by an “effective bandgap” model. In contrast, no significant changes of the short-circuit current densit...

Synthesis and Shape Control of Copper Tin Sulphide Nanocrystals and Formation of Gold–Copper Tin Sulphide Hybrid Nanostructures

Hexagonal prismatic Cu3SnS4 nanoparticles and nanorods were synthesized by a hot-injection procedure. Changing the reaction conditions leads to the formation of different shapes. When oleylamine is used as a solvent, hexagonal prismatic particles are obtained, while a reaction in octadecene results in the formation of nanorods. The growth process of copper tin sulphide starts with the formation of djurleite copper sulphide seeds. Their reaction with Sn4+ ions leads to the formation of Cu3SnS4. These Cu3SnS4 nanocrystals form Au-Cu3SnS4 hybrid nanostructures by reaction with gold seeds