“Ag2HgI4” a thermochromic compound with superionic conducting properties: Synthesis, characterization and investigation of graphene-based nanocomposites

• Published in: Journal of molecular liquids Vol. 252; pp. 112 - 120
• Main Authors: Soofivand, Faezeh, Salavati-Niasari, Masoud
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2018
• Subjects: Ag2HgI4; Graphene; Nanostructures; Phase transition; Superionic conductor; Thermochromic compound; Nanostructures; Graphene; Ag2HgI4; Superionic conductor; Thermochromic compound; Phase transition
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2017.12.129

In this work, silver tetraiodomercurate (Ag2HgI4) nanoparticles as a compound with two properties: thermochromism with performance as sensor and superionic conducting with solid electrolytic application were synthesized by simple co-precipitation method. According to the results, it was found that decreasing the size to nano-scale increases transition temperature and conductivity of Ag2HgI4. Also, the investigation showed that frequency can be effective on conductivity so that increasing it increases the conductivity. Besides, the effect of graphene as a substrate with unique properties on conductivity, phase transition temperature and optical properties of Ag2HgI4 was studied. As expected, the transition temperature and energy of optical absorption of nanocomposites were lower than the pure nanoparticles that is due to high thermal conductivity of graphene. On the other sides, the conductivity of nanocomposites increased by creating the new conductance channel for moving the mobile ions. The findings confirmed that the properties of thermochromic compounds and superionic conductors can be changed by impurities, size and component. [Display omitted] •Pure Ag2HgI4 as a thermochromic compound with superionic properties in nano-scale was synthesized.•Investigation of the effect of size on phase transition temperature of this compound was studied.•Decreasing the thermal conductivity is due to scattering the phonons at the grain boundaries of them.•The finding showed that the presence of graphene can be effective on conductivity.•High surface area of graphene provides the new channel for mobile ions.