Controlled Reduction of Sn in the Complex Iodide CsSnI with Metallic Gallium.

Metal gallium as a low-melting solid was applied in a mixture with elemental iodine to substitute tin(IV) in a promising light-harvesting phase of CsSnI by a reactive sintering method. The reducing power of gallium was applied to influence the optoelectronic properties of the CsSnI phase via partial reduction of tin(IV) and, very likely, substitute partially Sn by Ga. The reduction of Sn to Sn in the CsSnI phase contributes to the switching from -type conductivity to n-type, thereby improving the total concentration and mobility of negative-charge carriers.

Indium Doping of Lead-Free Perovskite CsSnI.

Structure and properties of an inorganic perovskite CsSnI demonstrated its potential as a light-harvester or electron-hole transport material; however, its optoelectronic properties are poorer than those of lead-based perovskites. Here, we report the way of light tuning of absorption and transport properties of cesium iodostannate(IV) CsSnI via partial heterovalent substitution of tin for indium. Light absorption and optical bandgaps of materials have been investigated by UV-vis absorption and photoluminescent spectroscopies.