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

Abstract 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.