Tailored Engineering of an Unusual (C₄H₉NH₃)₂(CH₃NH₃)₂Pb₃Br₁₀ Two‐Dimensional Multilayered Perovskite Ferroelectric for a High‐Performance Photodetector

Abstract

Two-dimensional (2D) layered hybrid perovskites have shown great potential in optoelectronics, owing to their unique physical attributes. However, 2D hybrid perovskite ferroelectrics remain rare. The first hybrid ferroelectric with unusual 2D multilayered perovskite framework, (C₄ H₉ NH₃ )₂ (CH₃ NH₃ )₂ Pb₃ Br₁₀ (1), has been constructed by tailored alloying of the mixed organic cations into 3D prototype of CH₃ NH₃ PbBr₃ . Ferroelectricity is created through molecular reorientation and synergic ordering of organic moieties, which are unprecedented for the known 2D multilayered hybrid perovskites. Single-crystal photodetectors of 1 exhibit fascinating performances, including extremely low dark currents (ca. 10^-12 A), large on/off current ratios (ca. 2.5×10³ ), and very fast response rate (ca. 150 μs). These merits are superior to integrated detectors of other 2D perovskites, and compete with the most active CH₃ NH₃ PbI₃ .