Enhancing interlayer hydrogen bonds of 2D Ruddlesden-Popper perovskite toward stable polarization-sensitive photodetection

2D Ruddlesden-Popper (RP) polar perovskite, displaying the intrinsic optical anisotropy and structural polarity, has a fantastic application perspective in self-powered polarized light detection. However, the weak van der Waals interaction between the organic spacing bilayers is insufficient to preserve the stability of RP-type materials. Hence, it is of great significance to explore new stable 2D RP-phase candidates. In this work, we have successfully constructed a highly-stable polar 2D perovskite, (t-ACH)₂PbI₄ (1, where t-ACH⁺ is HOOC₈H₁₂NH₃⁺), by adopting a hydrophobic carboxylate trans-isomer of tranexamic acid as the spacing component. Strikingly, strong O-H···O hydrogen bonds between t-ACH⁺organic bilayers compose the dimer, thus decreasing van der Waals gap and enhancing structural stability. Besides, such orientational hydrogen bonds contribute to the formation of structural polarity and generate an obvious bulk photovoltaic effect in 1, which facilitates its self-powered photodetection. As predicted, the combination of inherent anisotropy and polarity leads to self-powered polarized-light detection with a high ratio of around ∼5.3, superior to those of inorganic 2D counterparts. This work paves a potential way to design highly-stable 2D perovskites for high-performance optoelectronic devices.