Synthesis and characterization of Zn1-xAcxS (0≤x≤0.1) nanocrystalline quantum dots prepared via soft mechanochemical approach

Abstract

Here, we report a first example of nanocrystalline Zn1-xAcxS (0 ≤ x ≤ 0.1) quantum dots prepared via soft mechanochemical approach. The incorporation of up to 10 at.% of Ac ions into the ZnS quantum dots (QDs) allows preservation of the cubic crystal structure as was confirmed by X-ray diffraction and the selected area electron diffraction. The transmission electron microscopy demonstrated that the increase of the Ac ion doping give rise to the increase of the particle size from 4.8 ± 0.3 nm to 17.9 ± 0.3 nm. The energy dispersive X-ray spectroscopy measurements indicated that the Zn1-xAcxS powders are stoichiometric at all Ac ion substitutions. The substitution of Zn ions by Ac ions in the Zn1-xAcxS nanocrystals was also verified by the Raman and FTIR spectroscopy measurements. The incorporation of the Ac ions into the ZnS QDs showed a red shift of the optical absorption and photoluminescence (PL) spectra. An enhancement of the PL intensity and a decrease of the PL spectrum width were observed due to the partial substitution by the Ac ions in the Zn sites of the ZnS nanocrystals. These properties make the Zn1-xAcxS QDs promising candidates for both light emitting and laser diodes applications.