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

Two-dimensional (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 PbI2 , we design a novel DJ-perovskitoid (DGA)PbI4 . From the comparison of (DGA)PbI4 to other 2D PSCs, we 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 cm2 V-1 s-1 ) and a pronounced sensitivity of 4869.0 μC Gyair -1 cm-2 are achieved using (DGA)PbI4 , which are the best in 2D Pb-based PSC devices to date. Finally, the (DGA)PbI4 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. This article is protected by copyright. All rights reserved.