Synthesis and Shape Control of CuInS₂ Nanoparticles

Abstract

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.

Optimization of the recipe for the synthesis of CuInS2/ZnS nanocrystals supported by mechanistic considerations

“…In agreement with previous reports, ZnS shell improved the intensity of absorption and emission [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. The dependence of the PL intensity was no more monotonic; for example, it exhibited a maximum at the synthesis time of about 60 min with improved QY of 65.5%.…”

“…CIS or CIS/ZnS QDs with spherical, triangle, rod-like, hexagonal, and spindle shapes were synthesized using different ligands such as TOP, oleylamine (OLA), DDT, DMF, OA, and trioctylphosphic oxide (TOPO) [22][23][24][25][26][27][28][29][30][31][32]. Until now, the PL QYs of CIS/ZnS in the reach stage have been up to more than 80% [24,25,27,33].…”

Effect of Nanoparticles Shape on the Efficiency of Hybrid Solar Cells

“…reaction time and temperature). In the case of CuInS 2 colloidal synthesis, CuInS 2 and oleylamine, trioctylphosphine oxide (TOPO), was injected in a mixture by 1-dodecanethiol, tert-dodecanethiol [11]. This solution was maintained at 240 o C, resulting in the formation of elongated CIS nanoparticles that had approximately uniform size distribution.…”

“…It was observed that 75 seconds after injection, nanoparticles size increased, resulting in a squarelike shape ( Figure 2). After 80 seconds, the CIS particles reached an elongated shape, which then increased along the (002) axis and had an orientations perpendicular to the axis (100) [11]. CIS elongated shape had an optical absorption between 400 nm and 900 nm.…”

Selective Growth of Gold onto Copper Indium Sulfide Selenide Nanoparticles

“…It has been shown by the Banin group [1] that the heterogeneous growth behaviour of gold nanocrystals on nanorods is significantly different for different cadmium chalcogenides, such as CdSe and CdS [1]. We applied CuInS 2 NPs, synthesized according to a method described previously [23], in order to find out, whether a selective growth of gold nanocrystals is also possible on other I-III-VI NPs. In this reaction, the growth behaviour of gold is different.…”