Spacer Conformation Induced Multiple Hydrogen Bonds in 2D Perovskite toward Highly Efficient Optoelectronic Devices

Abstract Two‐dimensional (2D) Dion–Jacobson (DJ) perovskites typically outperform Ruddlesden–Popper (RP) analogs in terms of photodetection (PD). However, the mechanism behind this enhanced performance remains elusive. Theoretical calculations for elucidating interlayer spacer conformation‐induced multiple hydrogen bonds in 2D perovskite are presented, along with the synthesis of DPAPbBr 4 (DPB) single crystals (SCs) and their PD properties under X‐ray/ultraviolet (UV) excitation. The high‐quality DPB SC enhances PD with exceptional photoresponse attributes, including a high on/off ratio (4.89 × 10 4 ), high responsivity (2.44 A W⁻ 1 ), along with large dynamic linear range (154 dB) and low detection limit (7.1 nW cm⁻ 2 ), which are currently the best results among 2D perovskite SC detectors, respectively. Importantly, high‐resolution images are obtained under UV illumination with weak light levels. The SC X‐ray detector exhibits a high sensitivity of 663 µC Gy air ⁻ 1 cm –2 at 10 V and a detection limit of 1.44 µGy air s⁻ 1 . This study explores 2D DJ perovskites for efficient and innovative optoelectronic applications.