Antisolvent-assisted Crystallization of Centimeter-sized Lead-free Bismuth Bromide Hybrid Perovskite Single Crystals with X-ray Sensitive Merits

Hybrid bismuth halides perovskites have emerged as promising candidates for X-ray detection, due to the strong absorptivity of high-energy X-ray photons, high resistivity, large carrier diffusion length and low toxicity. However, the mostly investigated hybrid bismuth iodides single crystals are usually opaque and require a harsh synthesis process. Herein, novel one-dimensional (1D) pentamethylenediamine bismuth bromide (PDA)BiBr₅ single crystals were synthesized via an antisolvent-assisted crystallization method at room temperature. Bulk (PDA)BiBr₅ single crystals have sizes of 10×1.3×1.5 mm³ and high transparency. They are shown to have low density of defects of 2.0×10¹⁰ cm⁻³ and obvious photoconductivity. Moreover, they exhibit large bulk resistivity of 2.13×10¹¹ Ω cm and good X-ray attenuation coefficient. Consequently, the vertical structured (PDA)BiBr₅ single crystal X-ray photoconductor produces a sensitivity of 3.8 μC Gy_air⁻¹ cm⁻². This study provides a facile strategy for synthesizing bulk hybrid bismuth bromides single crystals with potential X-ray detection application.