Centimeter-Sized Molecular Perovskite Crystal for Efficient X-Ray Detection

Molecular perovskites have demonstrated great potential for ferroelectrics and nonlinear optics; however, their charge transport properties for optoelectronics have rarely been explored. Here, understanding of charge transport behavior of molecular perovskite under X-ray excitation based on centimeter-scale TMCM-CdCl₃ (TMCM⁺, trimethylchloromethyl ammonium) single crystal is demonstrated. The crystal is fabricated from an aqueous solution and exhibits a large bandgap of 5.51 eV, with the valence band maximum mainly dominated by the Cl-p/Cd-d states and the conduction band minimum primarily by Cd-s/Cl-p states. Charge mobility exceeding 40 cm² V⁻¹ s⁻¹ and mobility–lifetime (µτ) product on the order of 10⁻⁴ cm² V⁻¹ for the crystal are observed. These excellent optoelectronic properties translate to an efficient photoresponse under X-ray excitation, with the sensitivity reaching 128.9 ± 4.64 µC Gy_air⁻¹ cm⁻² [fivefold higher than that of the commercialized amorphous selenium (α-Se)] and a low detection limit of 1.06 μC Gy_air⁻¹ s⁻¹ (10 V bias). This work pioneers a superior metal-based molecular perovskite single-crystal based paradigm for optoelectronic investigation, which may lead to the discovery of a new generation of X-ray detection and imaging materials.