Centimeter-Sized Single Crystals of Dion-Jacobson Phase Lead-Free Double Perovskite for Efficient X-ray Detection.

2D Dion-Jacobson (DJ) phase hybrid perovskites have shown great promise in the photoelectronic field owing to their outstanding optoelectronic performance and superior structural rigidity. However, DJ phase lead-free double perovskites are still a virgin land with direct X-ray detection. Herein, we have designed and synthesized a new DJ phase lead-free layered double perovskite of (HIS) 2 AgSbBr 8 (1, HIS 2+  = histammonium). Centimeter-sized (18 × 10 × 5 mm 3 ) single crystals of 1 are successfully grown via the temperature cooling technique, exhibiting remarkable semiconductive characteristics such as a high resistivity (2.2 × 10 11  Ω cm), a low trap state density (3.56 × 10 10 cm -3 ), and a large mobility-lifetime product (1.72 × 10 -3 cm 2 V -1 ). Strikingly, its single-crystal-based X-ray detector shows a high sensitivity of 223 µC Gy -1 air cm -2 under 33.3 V mm -1 , a low detection limit (84.2 nGy air s -1 ) and superior anti-fatigue. As far as we know, we firstly demonstrates the potential of 2D DJ phase lead-free hybrid double perovskite in X-ray detection, showing excellent photoelectric response and operational stability. This work will pave a promising pathway to the innovative application of hybrid perovskites for eco-friendly and efficient X-ray detection.