Trifunctional Kinetic Regulation Enables Low-Defect Solution Grown Single Crystals for X-Ray Detection

All-inorganic 0D material exhibits excellent stability and shows great potential in the field of X-ray detection. However, their practical performance is limited by intrinsic point defects and solvent incorporation. Herein, we propose a universal trifunctional kinetic regulation strategy utilizing iodoacetic acid (IAA) as a multifunctional additive to dynamically regulate crystal growth. Through a synergistic mechanism, the carboxyl group (-COOH) coordinates with undercoordinated Pb²⁺ to suppress deep-level traps, released iodide ions (I^-) compensate for potential iodine vacancies (V_I), while the bulky -CH₂I group provides steric hindrance against solvent incorporation. This molecular engineering approach yields Cs₄PbI₆ single crystals that exhibit a resistivity of 1.95 × 10¹⁰ Ω cm, and a remarkably enhanced carrier mobility-lifetime product (µτ) of 2.18 × 10^-4 cm² V^-1. X-ray detectors based on these crystals achieve a high sensitivity of 897.4 µC Gy_air cm^-2 and a low detection limit of 29.81 nGy_air s^-1 under an electric field of 1000 V cm^-1 for 80 keV X-ray detection, alongside robust operational and environmental stability. This work provides a molecular-level design strategy for high-performance perovskite single-crystal X-ray detectors.