Directed Assembly of Ordered Mixed‐Spacer Quasi‐2D Halide Perovskites through Homomeric Chains of Intermolecular Bonds

Abstract

AbstractTwo‐dimensional (2D) halide perovskites (HPs) are of significant interest to researchers because of their natural structural frameworks and intriguing optoelectronic properties. However, the direct fabrication of ordered mixed‐spacer quasi‐2D HPs remains challenging. Herein, a synthetic strategy inspired by the principle of supramolecular synthons is employed for the self‐assembly of a series of ordered mixed‐spacer bilayered HPs. The key innovation involves the introduction of intermolecular hydrogen bonds using a bifunctional 3‐aminopropionitrile cation. Three homogeneous n = 2 structures are obtained, with a subtly ordered perovskite connected by two distinct types of organic cation layers, resulting in a recurrent ABABʹ stacking sequence. These three compounds exhibit attractive semiconducting properties. Moderate bandgaps in the range of 2.70 to 2.76 eV with an absorption wavelength range of 448–459 nm exhibit excellent photoelectric response. Moreover, the ordered structures facilitate excellent polarization‐sensitive photodetection, with an impressive on/off ratio of 103. The response speed ranged from 298 to 381 µs, and the out‐of‐plane polarization‐related dichroism ratio is determined to be 1.19. Such ordered mixed‐spacer bilayered perovskites have not been reported. These results enrich the HPs system and play a significant role in the direct assembly of novel perovskites with ordered structures.