Condensed Matter and Interphases
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Condensed Matter and Interphases. 2021;23(2): 236–244 ISSN 1606-867Х (Print) ISSN 2687-0711 (Online) Condensed Matter and Interphases Kondensirovannye Sredy i Mezhfaznye Granitsy https://journals.vsu.ru/kcmf/ Original articles Research article https://doi.org/10.17308/kcmf.2021.23/3435 Phase relations in the CuI-SbSI-SbI3 composition range of the Cu–Sb–S–I quaternary system P. R. Mammadli1,2, V. A. Gasymov2, G. B. Dashdiyeva3, D. M. Babanly1,2* 1Azerbaijan State Oil and Industry University, French - Azerbaijani University, 183 Nizami str., Baku AZ-1010, Azerbaijan 2Institute of Catalysis and Inorganic Chemistry of the Azerbaijan National Academy of Sciences, 113 H. Javid ave., Baku AZ-1143, Azerbaijan 3Baku Engineering University, 120 Hasan Aliyev str., Baku AZ-0102, Azerbaijan Abstract The phase equilibria in the Cu-Sb-S-I quaternary system were studied by differential thermal analysis and X-ray phase analysis methods in the CuI-SbSI-SbI3 concentration intervals. The boundary quasi-binary section CuI-SbSI, 2 internal polythermal sections of the phase diagram, as well as, the projection of the liquidus surface were constructed. Primary crystallisation areas of phases, types, and coordinates of non- and monovariant equilibria were determined. Limited areas of solid solutions based on the SbSI (b-phase) and high-temperature modifications of the CuI (a1- and a2- phases) were revealed in the system. The formation of the a1 and a2 phases is accompanied by a decrease in the temperatures of the polymorphic transitions of CuI and the establishment of metatectic (3750C) and eutectoid (2800C) reactions. It was also shown, that the system is characterised by the presence of a wide immiscibility region that covers a significant part of the liquidus surface of the CuI and SbSI based phases. Keywords: Copper (I) iodide, Antimony iodide, Antimony sulfoiodide, Cu-Sb-S-I system, Phase diagram, Solid solutions Acknowledgements: the work has been partially supported by the Science Development Foundation under the President of the Republic of Azerbaijan, a grant № EİF-BGM-4-RFTF-1/2017-21/11/4-M-12. For citation: Mammadli P. R., Gasymov V. A., Dashdiyeva G. B., Babanly D. M. Phase relations in the CuI-SbSI-SbI3 composition range of the Cu-Sb-S-I quaternary system. Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases. 2021;23(2): 236–244. https://doi.org/10.17308/kcmf.2021.23/3435 Для цитирования: Маммадли П. Р., Гасымов В. А., Дашдиева Д. Б., Бабанлы Д. М. Фазовые равновесия в области составов CuI–SbSI–SbI3 системы Cu–Sb–S–I. Конденсированные среды и межфазные границы. 2021;23(2): 236–244. https://doi.org/10.17308/kcmf.2021.23/3435 Parvin Rovshan Mammadli, e-mail: [email protected] © Mammadli P. R., Gasymov V. A., Dashdiyeva G. B., Babanly D. M., 2021 The content is available under Creative Commons Attribution 4.0 License. 236 Condensed Matter and Interphases / Конденсированные среды и межфазные границы 2021;23(2): 236–244 P. R. Mammadli et al. Original article 1. Introduction have been studied in detail. Copper (I) iodide Copper-antimony chalcogenides and phases CuI is a non-poisonous, wide-gap semiconductor based on them are considered to be potential possessing stable p-type electrical conductivity at candidates for the preparation of environmentally room temperature, fast-ionic conductivity at high friendly, low-cost functional materials possessing temperatures, an unusually large temperature novel desired characteristics [1–3]. The majority of dependency, negative spin-orbit splitting, ternary Cu–Sb-sulphides are naturally occurring etc [14–16]. It has wide application in light- minerals that have been widely explored as emitting diodes, solid-state dye-sensitised valuable electronic materials displaying high solar cells, high-performance thermoelectric photoelectric, photovoltaic, radiation detector, elements, etc [17, 18]. Antimony triiodide thermoelectric, etc. properties. Earth abundance SbI3 has been intensively studied as a dopant and environmental compatibility of these in thermoelectric materials, as a potential substances highlight the recent advances of material for radiation detectors, as cathodes in investigations on these materials [4–7]. solid-state batteries, in high-resolution image As it is known, one of the ways to increase microrecording, information storage, etc. [19– the efficiency of thermoelectric materials is 21]. SbSI exhibits important ferroelectricity, to complicate their composition and crystal piezoelectricity, photoconduction, dielectric structure [8]. In this regard, Cu-Sb chalcohalides polarisation properties and is widely used in the could be considered promising research objects fabrication of nanogenerators and nanosensors in terms of the search and design of new eco- [22–25]. friendly functional materials. However, we could CuI melts at 606 °C without decomposition not find literary information about the phase and has 3 modifications [26, 27]. The low- equilibria of the Cu–Sb–S–I quaternary system. temperature g-modification transforms to the There is a literary report about the formation, b-phase at 369 °C. The b-CuI phase exists in a crystal structure, and conductivity of the small temperature range (~ 10 K) and transforms into a-phase at 407 °C. SbI melts at 172 °C [28] Cu5SbS3I2 compound [9]. Cu5SbS3I2 crystallises in 3 the orthorhombic system, space group Pnnm with and crystallises to rhombohedral lattice [29]. the following lattice parameters a = 10.488(2), SbSI melts congruently at 300 °C [22,30]. Three b = 12.619(2), c =7.316(1) Å, and Z = 4 [9]. Electric phases of SbSI have been reported: ferroelectric conductivity and dielectric parameters of the (T < 20 °C), antiferroelectric (20 °C < T <140 °C) Cu–Sb–S–I glasses have been investigated in and paraelectric (T < 140 °C) [31]. Both in the order to evaluate their practical importance in paraelectric and ferroelectric phases, SbSI memory switching, electrical threshold, optical crystallises in the orthorhombic structure [32, 33]. switching devices, and so forth [10]. Crystallographic parameters of the constituent The search and design of new complex func- compounds of the system A are represented in tional materials require investigation of the re- Table 1. spective phase diagrams. The information accu- CuI–SbI3 and SbSI–SbI3 boundary mulated in phase diagrams of the corresponding quasi-binary sections of the quasi-ternary systems is always helpful in materials science for CuI–SbSI–SbI3 system have been investigated the development of advanced materials [11–13]. by [35–37], respectively. CuI–SbI3 system Considering above mentioned facts, in terms forms a monotectic phase diagram. At the of the search for new multicomponent phases, monotectic equilibrium temperature (~ 220 °C) the immiscibility region ranges within ~15– the concentration plane Cu2S–CuI–SbI3–Sb2S3 of the Cu–Sb–S–I quaternary system is of great 93 mol% SbI3 concentration interval [35]. interest. The present contribution is dedicated SbSI–SbI3 quasi-binary section is characterised to the study of physicochemical interaction in by a eutectic equilibrium at 160 °C [12, 30]. the CuI–SbSI–SbI (A) concentration area of the 3 2. Experimental part above-mentioned concentration plane. A CuI binary compound, as well as, antimony Primary compounds of the system (A) and iodine elementary components of the Alfa possessing interesting functional properties 237 Condensed Matter and Interphases / Конденсированные среды и межфазные границы 2021;23(2): 236–244 P. R. Mammadli et al. Original article Table 1. Crystal lattice types and parameters of the CuI, SbI3, and SbSI compound Compound, Crystal lattice type and parameter, Å modification LT–CuI Cubic lattice; SpGr. F; a = 6.05844(3) Å [27] Trigonal: SpGr. P3; a = 4.279±0.002; c = 7.168±0.007 (673 K) [34] HT1–CuI Triqonal: SpGr. R-3; a = 4.29863(11); c = 21.4712(6) (603 K) [26] Triqonal: SpGr. R-3 a = 4.30571 (12); c = 21.4465(7) (608 K) [26] HT2–CuI Cubic: SpGr. F a = 6.16866(6) [27] SbI3 Rhombohedral: SpGr. ; a = 7.48; c = 20,90; Z = 6 [29] Orthorhombic: SpGr. Pnam; a = 8.556(3); b = 10.186(4); c = 4.111(2); z = 4 [32] SbSI Orthorhombic: SpGr. Pna21; a = 8.53; b = 10.14; c = 4.10 [33] The symbols HT2, HT1, and LT indicate high, intermediate, and low-temperature modifications of CuI, respectively. Aesar German brand (99.999 % purity) were used out at room temperature on the Bruker D2 in the course of experimental studies. PHASER diffractometer with CuKa1 radiation. Binary SbI3 and ternary SbSI compounds were The diffraction patterns were indexed using the synthesised from the elemental components in Topas 4.2 Software (Bruker). –2 evacuated (~10 Pa) silica ampoules followed by a 3. Results and discussion specially designed method taking into account the high volatility of iodine and sulphur. The synthe- A co-analysis of experimental results together sis was performed in an inclined two-zone furnace, with the literature data regarding boundary binary systems helped us to obtain the full with the hot zone kept at a temperature 20–30 °C description of phase equilibria in the CuI-SbSI- higher than the corresponding melting point of the SbI concentration triangle. synthesised compound, whereas the temperature 3 of the cold zone was kept at about 130 °C. After the 3.1. CuI–SbSI boundary quasi-binary system main portion of iodine and sulphur had reacted, The powder X-ray diffraction patterns of the the ampoules were relocated such that the pro- thermally treated CuI–SbSI alloys are given in ducts could melt at 230 °C (SbI3) and 450 °C (SbSI). Fig. 1. As can be seen, diffraction patterns of After stirring the homogeneous liquid at this tem- samples in the full composition range consist perature, the furnace gradually cooled. The puri- of the diffraction peaks of the SbSI and low- ty and individuality of the obtained products were temperature modification of CuI. monitored using DTA and PXRD methods.