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Mechanochemically Synthesized CuFeSe₂ Nanoparticles and Their Properties

100%

Dutková E., Škorvánek I., Sayagués M., Zorkovská A., Kováč J., Baláž P.

Acta Physica Polonica A

2017

vol. 131

issue 4

1156-1158

The mechanochemical synthesis of nanocrystalline CuFeSe₂ particles prepared by high-energy milling in a planetary mill in an argon atmosphere from copper, iron, and selenium for 60 min is reported for the first time. The CuFeSe₂ nanoparticles crystallize in tetragonal structure with mean crystallite size of about 32±1 nm. High resolution transmission electron microscopy measurements confirmed the presence of agglomerates which are formed by small nanocrystalline domains (5-40 nm). The magnetic data revealed that paramagnetic CuFeSe₂ nanoparticles coexist with a small amount of ferromagnetic impurities at room temperature. The magnetic transition towards a weak ferromagnetic or ferrimagnetic behavior occurs in CuFeSe₂ at approximately 79 K. The band gap of the CuFeSe₂ particles is 0.95 eV which is wider than the band gap in bulk materials (0.16 eV), which could be in many aspects of application more beneficial.

Mechanochemical Synthesis and Characterization of II-VI Nanocrystals: Challenge for Cytotoxicity Issues

84%

Baláž P., Jardin R., Dutková E., Sayagués M., Baláž M., Mojžišová G., Mojžiš J., Turianicová E., Fabián M.

Acta Physica Polonica A

2012

vol. 122

issue 1

224-229

CdSe@ZnS nanocrystals have been prepared by a two-step solid state mechanochemical synthesis. CdSe prepared from elements in the first step is mixed with ZnS synthesized from zinc acetate and sodium sulfide in the second step. The crystallite size of the new type CdSe@ZnS nanocrystals determined by X-ray diffraction Rietveld refined method was 35 nm and 10 nm for CdSe and ZnS, respectively. Energy dispersive/transmission electron microscopy/energy dispersive spectroscopy methods show good crystallinity of the nanoparticles and scanning electron microscopy elemental mapping illustrate consistent distribution of Cd, Se, Zn and S elements in the bulk of samples. UV-VIS spectra show an onset at 320 nm with calculated bandgap 3.85 eV. This absorption arises from the vibration modes of Zn-S bonds. The nanocrystals show the blue shift from the bandgap of bulk ZnS (3.66 eV). The synthesized CdSe@ZnS nanocrystals have been tested for dissolution, cytotoxicity and L-cysteine conjugation. The dissolution of Cd was less than 0.05 μg mL^{-1} (in comparison with 0.8 μg mL^{-1} which was evidenced for CdSe alone). The very low cytotoxic activity for selected cancer cell lines has been evidenced. CdSe@ZnS nanocrystals coated with L-cysteine are water-soluble and have a great potential in biomedical engineering as fluorescent labels.

Mechanochemically Synthesized Nanocrystalline Sb_2S_3 Particles

84%

Dutková E., Sayagués M., Real C., Zorkovská A., Baláž P., Šatka A., Kováč J., Ficeriová J.

vol. 126

issue 4

943-946

Nanocrystalline Sb_2S_3 particles have been synthesized from Sb and S powders by high-energy milling in a planetary mill using argon protective atmosphere. X-ray diffraction, particle size analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, electron diffraction, high resolution transmission electron microscopy, UV-VIS, and differential scanning calorimetry methods for characterization of the prepared particles were applied. The powder X-ray diffraction pattern shows that Sb_2S_3 nanocrystals belong to the orthorhombic phase with calculated crystallite size of about 36 nm. The nanocrystalline Sb_2S_3 particles are constituted by randomly distributed crystalline nanodomains (20 nm) and then these particles are forming aggregates. The monomodal distribution of Sb_2S_3 particles with the average hydrodynamic parameter 210 nm was obtained. The quantification of energy dispersive X-ray spectroscopy analysis peaks give an atomic ratio of 2:3 for Sb:S. The optical band gap determined from the absorption spectrum is 4.9 eV, indicating a considerable blue shift relative to the bulk Sb_2S_3. Differential scanning calorimetry curves exhibit a broad exothermic peak between 200 and 300°C, suggesting recovery processes. This interpretation is supported by X-ray diffraction measurements that indicate a 23-fold increase of the crystallite size to about 827 nm as a consequence of application of high temperature process. The controlled mechanochemical synthesis of Sb_2S_3 nanoparticles at ambient temperature and atmospheric pressure remains a great challenge.

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3 Acta Physica Polonica A

1 2017

1 2014

1 2012

3 Baláž P.

3 Dutková E.

3 Sayagués M.

2 Kováč J.

2 Zorkovská A.

1 Baláž M.

1 Fabián M.

1 Ficeriová J.

1 Jardin R.

1 Mojžiš J.

1 Mojžišová G.

1 Real C.

1 Turianicová E.

1 Šatka A.

1 Škorvánek I.

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Mechanochemically Synthesized CuFeSe₂ Nanoparticles and Their Properties

Mechanochemical Synthesis and Characterization of II-VI Nanocrystals: Challenge for Cytotoxicity Issues

Mechanochemically Synthesized Nanocrystalline Sb_2S_3 Particles