Electron-Phonon Coupling Suppression by Enhanced Lattice Rigidity in 2D Perovskite Single Crystals for High-Performance X-Ray Detection.

Zhang, Bobo; Zheng, Tao; You, Jiaxue; Ma, Chuang; Liu, Yucheng; Zhang, Lu; Xi, Jun; Dong, Guohua et al. · Adv Mater · 2023

basic_science · Level V

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Abstract

2D Dion-Jacobson (DJ) perovskite single crystals (PSCs) usually demonstrate better X-ray detection performance than Ruddlesden-Popper (RP) PSCs. However, the mechanism of the improved performance is still elusive. Here, by the aid of strong interactions between dimethylbiguanide (DGA) and PbI<sub>2</sub> , a novel DJ-perovskitoid (DGA)PbI<sub>4</sub> is designed. From the comparison of (DGA)PbI<sub>4</sub> to other 2D PSCs, it is discovered that the tiniest lattice distortion and increased hydrogen bonds in the atom-scaled analysis strengthen lattice rigidity and weaken electron-phonon coupling to suppress disordered scattering of carriers, resulting in significantly improved carrier transport and stability. Therefore, high carrier mobility (78.1 cm<sup>2</sup> V<sup>-1</sup> s<sup>-1</sup> ) and a pronounced sensitivity of 4869.0 µC Gy<sub>air</sub> <sup>-1</sup> cm<sup>-2</sup> are achieved using (DGA)PbI<sub>4</sub> , which are the best in 2D Pb-based PSC devices to date. Finally, the (DGA)PbI<sub>4</sub> devices exhibit good spatial resolution in X-ray imaging and excellent long-term stability to work as a promising candidate for medical diagnostics and nondestructive determination.