Properties of mechanochemically synthesized nanocrystalline Bi 2 S 3 particles Erika Dutková a,n , María J. Sayagués b , Anna Zorkovská a , Concepcion Real b , Peter Baláž a , Alexander Šatka c , Jaroslav Kováč c a Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 040 00 Košice, Slovakia b Institute of Material Science of Seville (CSIC-US), 410 92 Sevilla, Spain c Institute of Electronics and Photonics, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava, Slovakia article info Keywords: Bismuth sulphide Mechanochemical synthesis Semiconductor abstract Nanocrystalline Bi 2 S 3 particles have been synthesized from Bi and S powders by high- energy milling in a planetary mill. Structural and microstructural characterization of the prepared particles, including phase identification, specific surface area measurement and particle size analysis has been carried out. The optical properties were measured by spectroscopic methods and the structural stability up to 500 1C was studied by thermal analysis. The production of orthorhombic Bi 2 S 3 with crystallite size of about 26 nm was confirmed by X-ray diffraction. The nanocrystals tend to agglomerate due to their large specific surface area. Accordingly, the average hydrodynamic diameter of the mechan- ochemically synthesized particles is 198 nm. EDS analysis shows that the synthesized material is pure Bi 2 S 3 . The band gap of the Bi 2 S 3 nanoparticles is 4.5 eV which is wider than that in bulk materials. The nanoparticles exhibit good luminescent properties with a peak centered at 490 and 390 nm. Differential scanning calorimetry curves exhibit a broad exothermic peak between 200 and 300 1C, suggesting recovery processes. This interpreta- tion is supported by X-ray diffraction measurements that indicate a 10-fold increase of the crystallite size to about 230 nm. The controlled mechanochemical synthesis of Bi 2 S 3 nanoparticles at ambient temperature and atmospheric pressure remains a great chal- lenge. & 2014 Elsevier Ltd. All rights reserved. 1. Introduction The synthesis of one-dimensional (1D) nanostructured metal chalcogenides has been the focus of attention because of their important physical and chemical proper- ties, as well as their applications in semiconductors, pigments, luminescence devices, solar cells, IR detectors, and thermoelectric devices. Bismuth sulphide, Bi 2 S 3 is known to be attractive material for photoelectrochemical applications as it has a reasonably narrow band gap (E g ¼ 1.3 eV) and a reasonable incident photon to electron conversion efficiency. Bi 2 S 3 is also a promising semiconductor material for applications in photovoltaic cells and thermoelectric cooling technolo- gies because of its environmental compatibility. Conventionally, Bi 2 S 3 is prepared by methods such as direct reaction of bulk bismuth with sulphur vapour in a quartz vessel [1] and thermal decomposition of various precursors [2]. In these methods, high temperature is required and the final products always contain some impurities [3]. In the recent years, Bi 2 S 3 nanowires, Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/mssp Materials Science in Semiconductor Processing http://dx.doi.org/10.1016/j.mssp.2014.05.057 1369-8001/& 2014 Elsevier Ltd. All rights reserved. n Corresponding author. E-mail address: dutkova@saske.sk (E. Dutková). Materials Science in Semiconductor Processing 27 (2014) 267–272