Triiodide Hybrid (n-Propylammonium)₄SbI₆·I₃ Wafers for High-Performance X-ray Detection

A large average atomic number, an excellent mobility-charge carrier lifetime, and high sensitivity are intensely required for a semiconductor material to achieve high-performance x-ray detection. Here, we present a new lead-free organic–inorganic hybrid (n-propylammonium)₄SbI₆·I₃ that is designed and constructed with triiodide ions. The incorporated triiodide component can enhance the proportion of large atomic numbers, thereby improving the average atomic number. Semiconductor performance analysis shows that the triiodide-based hybrid exhibits a narrow bandgap of 1.48 eV and a high resistivity (1.07 × 10¹⁰ Ω·cm). Moreover, the wafer-based x-ray detectors exhibit a large mobility-lifetime product of 1.2 × 10⁻³ cm²/V, a high sensitivity of 2.5 × 10³ μC/(Gy_air·cm²), and a low detection limit of 390 nG_yair/s, as well as excellent material and device stability. This work provides new insights to rationally design lead-free hybrid semiconductors for high-performance radiation detectors.