Tuning Phase Stability and Band Gap in Vacancy-Ordered Double Perovskites Rb CsSnI Through Variations in A-Site Cation.

Tetravalent Sn-iodide-based ASnI vacancy-ordered double perovskites have received extensive attention in the recent past. Their phase instabilities, triggered by temperature or compositional changes, offer a pathway to control structure and functional properties. Here, we report the solution synthesis of RbSnI, RbCsSnI, and CsSnI, and their phase transition study using variable temperature powder X-ray diffraction (PXRD).

Vacancy Ordered Double Perovskites [N(CH)]SnX (X=Cl, Br, I): Thermal Phase Transition and Wide Range Optical Absorption.

(TMA)SnX (TMA=tetramethylammonium; X=Cl, Br, I) compounds form vacancy-ordered halide double perovskites (VODPs) with TMA cation in the A-site, Sn cation in the M-site and X anion in the halide site. This study reports the synthesis and the structural phase transition of (TMA)₂SnCl₆, (TMA)SnClBr, (TMA)₂SnBr₆, and (TMA)₂SnI₆. All four halides crystallize in a cubic Fd c symmetry at room temperature.

Longitudinal strain enhancement and bending deformations in piezoceramics.

Piezoelectric materials directly convert between electrical and mechanical energies. They are used as transducers in applications such as nano-positioning and ultrasound imaging. Improving the properties of these devices requires piezoelectric materials capable of delivering a large longitudinal strain on the application of an electric field.