Synthesis and Characterization of New Hybrid Organic-Inorganic Metal Halides [(CH 3 ) 3 SO]M 2 I 3 (M = Cu and Ag).

Recently, all-inorganic copper(I) metal halides have emerged as promising optical materials due to their high light emission efficiencies. This work details the crystal structure of the two hybrid organic-inorganic metal halides [(CH 3 ) 3 SO]M 2 I 3 (M = Cu and Ag) and their alloyed derivatives [(CH 3 ) 3 SO]Cu 2- x Ag x I 3 ( x = 0.2; 1.25), which were obtained by incorporating trimethylsulfoxonium organic cation (CH 3 ) 3 SO + in place of Cs + in the yellow-emitting all-inorganic CsCu 2 I 3 . These compounds are isostructural and centrosymmetric with the space group Pnma , featuring one-dimensional edge-sharing [M 2 I 3 ] - anionic double chains separated by rows of (CH 3 ) 3 SO + cations. Based on density functional theory calculations, the highest occupied molecular orbitals (HOMOs) of [(CH 3 ) 3 SO]M 2 I 3 (M = Cu and Ag) are dominated by the Cu or Ag d and I p orbitals, while the lowest unoccupied molecular orbitals (LUMOs) are Cu or Ag s and I p orbitals. [(CH 3 ) 3 SO]Cu 2 I 3 single crystals exhibit a semiconductor resistivity of 9.94 × 10 9 Ω·cm. Furthermore, a prototype [(CH 3 ) 3 SO]Cu 2 I 3 single-crystal-based X-ray detector with a detection sensitivity of 200.54 uCGy -1 cm -2 (at electrical field E = 41.67 V/mm) was fabricated, indicating the potential use of [(CH 3 ) 3 SO]Cu 2 I 3 for radiation detection applications.