Unprecedented Mixed Low-Dimensional Metal Halide Double Perovskite for Stable and Efficient X-Ray Detection

Double perovskites have shown great promise for direct X-ray detection due to their nontoxic nature and excellent phase stability. However, mixed low-dimensional double perovskites are still a virgin land with direct X-ray detection. Here, a millimeter-scale mixed low-dimensional double perovskite (4-AP)5AgBi3Br20 (1, 4-AP = 4-amidinopyridine) is successfully synthesized with a coexistence of 1D-0D structural motifs. Noteworthily, the 0D motif is isolated {BiBr6} octahedra and the 1D unit is the infinite chain ({AgBi2Br14}infinity). This is the first reported mixed low-dimensional (1D-0D) structure in Ag-Bi double perovskite. The unique 1D-0D architecture incorporates N & horbar;H<middle dot><middle dot><middle dot>Br hydrogen bonding and pi-pi interactions, which enhances material stability, restricts ion migration, and raises the ionic mobility activation energy (Ea) to 0.87 eV in the parallel direction (parallel to). Furthermore, 1 single crystal detector exhibits high sensitivity (1567.0 mu C Gy-1 cm-2, parallel to), and an ultra-low detection limit (38.1 nGy s-1, parallel to) which is more than 100 times lower than the conventional medical diagnostic value of 5.5 mu Gy s-1. In addition, 1 detector further achieves ultralow dark current drift (3.42 x 10-9 nA cm-1 s-1 V-1, at 100 V, parallel to). This study knocks on the door of novel mixed low-dimensional double perovskite with stable and efficient X-ray detection performances.