Sulfur Atom Manipulated Hard Lattice Rigidity for High‐Performance 2D Perovskite Single‐Crystal X‐ray Detector

Abstract 2D perovskite material shows excellent potential in X‐ray detection due to the advantages such as improved moisture stability, low dark current, and suppressed noise fluctuation. However, the soft lattice structure resulting from the flexible organic molecules significantly contributes to the enhanced electron‐phonon coupling and nonradiative recombination of carriers, thereby hindering the charge carrier transport and limiting the X‐ray detection performance of 2D perovskite. Herein, a sulfur atom‐introduced 2‐thiopheneethylamine lead iodide (TEA 2 PbI 4 ) perovskite single‐crystal is reported. The S atom‐induced π–π interactions facilitate a more tightly ordered arrangement of organic molecules within the perovskite, leading to reduced distortion of the inorganic octahedra, which enhances the lattice rigidity and suppresses non‐radiative recombination compared to other perovskites. Thus, the TEA 2 PbI 4 perovskite single‐crystal exhibits a high sensitivity of 2.45 × 10 4 µC·Gy air −1 ·cm −2 under 80 kV X‐ray irradiation. The X‐ray detection efficiency of TEA 2 PbI 4 can reach 85%, and the noise‐equivalent dose is as low as 82 pGy air , demonstrating its high signal/noise resolution capability.