Synthesis, structure, optoelectronic properties and stability of the lead-free tin-based organic-inorganic hybrid material

Organic-inorganic hybrid metal halides have emerged as promising materials, benefiting from their affordable production, synthetic simplicity, and superior optoelectronic properties. In this study, diisopropylamine was selected as the A-site organic ligand to construct tin-based halide organic–inorganic hybrid crystals, and synthesized two tin-based organic-inorganic hybrid single crystals, (C 6 H 16 N) 2 SnCl 6 and (C 6 H 16 N) 2 SnBr 6 , using the solvent evaporation method. A series of characterizations, including single-crystal and powder X-ray diffraction, Raman and IR spectroscopy, thermogravimetric analysis, and UV–Vis diffuse reflectance spectroscopy, were conducted on both single crystals. The test results show that (C 6 H 16 N) 2 SnCl 6 belongs to P2 1 /n in the monoclinic system, and (C 6 H 16 N) 2 SnBr 6 belongs to the Pca2 1 space group in the orthorhombic system. The cations of both crystals were [C 6 H 16 N] + , and the anions were [SnCl 6 ] 2− and [SnBr 6 ] 2− respectively. Both belong to the zero-dimensional perovskite single crystals with octahedral coordination. Infrared and Raman spectroscopy studies indicated the presence of [C 6 H 16 N] + , [SnCl 6 ] 2− and [SnBr 6 ] 2− . The good thermal stabilities of the two crystals are 180 °C and 190 °C respectively. The band gap of (C 6 H 16 N) 2 SnCl 6 was 3.98 eV, and that of (C 6 H 16 N) 2 SnBr 6 was approximately 2.78 eV. Both belong to wide band gap semiconductor materials. This research contributes to the advancement of environmentally benign, thermally stable organic-inorganic hybrid materials.