High-Tc Quadratic Nonlinear Optical and Dielectric Switchings in Fe-Based Plastic Crystalline Ferroelectric.

Plastic crystals, as a molecular material with multiple functions, have become a research hotspot in the exploration of new ferroelectric crystal compounds, especially due to their unique solid-solid phase transition properties. Based on this, we synthesized a new 0D organic-inorganic hybrid Fe-based plastic ferroelectric [(CH3)3NCH2CHCH2]FeCl4 (1), which has a high-temperature phase transition point of 393 K, obvious ferroelectric domains, and spontaneous polarization and has been tested by dielectric and piezoelectric power microscopy (PFM) and ultraviolet absorption (UV-vis). At room temperature, it crystallizes in the space group Cmc21 and has an obvious SHG switch. In addition, compound 1 also has an optical narrow band gap of 2.45 eV, indicating that compound 1 is a high-quality semiconductor material. This work advances the development of plastic ferroelectrics and provides an avenue for exploring the frequency-doubling response and optoelectronic properties of high-temperature plastic ferroelectrics.