Synthesis, Resistivity, and Thermal Properties of the Cubic Perovskite NH2CH=NH2SnI3and Related Systems

✍ Scribed by D.B. Mitzi; K. Liang

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 273 KB
• Volume: 134
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1997.7593

✦ Synopsis

Combining concentrated hydriodic acid solutions of tin(II) iodide and formamidine acetate in an inert atmosphere results in the precipitation of a new conducting organic-inorganic compound, NH 2 CH‫؍‬NH 2 SnI 3 , which at room temperature adopts a cubic perovskite structure. The lattice constant for NH 2 CH‫؍‬NH 2 SnI 3 is found to be a ‫؍‬ 6.316(1) A s , which is approximately 1.2% larger than that for the isostructural compound CH 3 NH 3 SnI 3 . The electrical resistivity of a pressed pellet of the new compound exhibits semimetallic temperature dependence from 10 to 300 K, with evidence of a structural transition at approximately 75 K. NH 2 CH‫؍‬NH 2 SnI 3 begins to slowly decompose in an inert atmosphere at temperatures as low as 200°°C, with bulk decomposition / melting occurring above 300°°C. The properties of the formamidinium-based perovskite are compared with those of the related cubic (at room temperature) perovskite CH 3 NH 3 SnI 3 and the mixed-cation system (CH 3 NH 3 ) 1؊x (NH 2 CH‫؍‬NH 2 ) x SnI 3 .