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

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, a novel DJ-perovskitoid (DGA)PbI4 is designed. From the comparison of (DGA)PbI4 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(2) V-1 s(-1)) and a pronounced sensitivity of 4869.0 mu C Gy(air)(-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.

Automated summary

A novel DJ-perovskitoid (DGA)PbI4 is designed by utilizing strong interactions between dimethylbiguanide (DGA) and PbI2, which exhibits better X-ray detection performance compared to other 2D PSCs. The improved performance is attributed to the minimized lattice distortion and increased hydrogen bonds, leading to enhanced lattice rigidity, weakened electron-phonon coupling, and suppressed disordered scattering of carriers. The (DGA)PbI4 devices achieve high carrier mobility (78.1 cm(2) V-1 s(-1)) and pronounced sensitivity (4869.0 mu C Gy(air)(-1)cm(-2)), making them the best 2D Pb-based PSC devices to date. They also demonstrate good spatial resolution in X-ray imaging and excellent long-term stability, showing promise for medical diagnostics and nondestructive determination.