Multiple non-covalent interactions synergistically construct room-temperature photoferroelectric semiconductor (Cl-PA)2PbCl4

Non-covalent interactions play an indispensable role in the construction of molecular ferroelectrics, as they can regulate the relative orientation and stacking mode between molecules. However, the difficulty and challenge lie in precisely designing and regulating the weak intermolecular interactions, ultimately generating macroscopically reversible spontaneous polarization through synergistic effects, thereby achieving ferroelectricity. Herein, we introduced halogenated ammonium Cl-PA + (Cl-PA + is 3-chloropropylaminium) to regulate non-covalent interactions in the structure of hybrid perovskite, and constructed a photoferroelectric semiconductor (Cl-PA) 2 PbCl 4 with large piezoelectric coefficient ( d 33 = 27.4 pC/N) and high Curie temperature ( T c = 353 K) through the synergistic effect of hydrogen bonding and halogen-halogen interactions. Compared with non-ferroelectric (PA) 2 PbCl 4 (PA + is n -propylaminium), the severe distortion of PbCl 6 octahedra, weakened N–H···Cl hydrogen bond between organic cations and inorganic frameworks, enhanced C–H···Cl hydrogen bond between cations, and the additional Cl···Cl interaction in the structure synergistically induce the ferroelectricity of (Cl-PA) 2 PbCl 4 . In addition, the large dipole moment of Cl-PA is also beneficial for constructing molecular ferroelectrics, and the synergetic effect of non-covalent interactions in (Cl-PA) 2 PbCl 4 provides the possibility for dipole flipping and symmetry breaking. Therefore, constructing molecular ferroelectrics through the synergistic effect of non-covalent interactions essentially utilizes dynamic coupling and precise equilibrium of multiple weak interactions to achieve the formation, stability, and external field flipping of spontaneous polarization. Through this collaborative design, ferroelectrics with high spontaneous polarization ( P s ), low coercive field, and wide temperature range can be achieved, which opens up new directions for flexible electronics and energy storage.