Superior ferroelectricity and nonlinear optical response in a hybrid germanium iodide hexagonal perovskite.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37208340.
- Also identified by DOI 10.1038/s41467-023-38590-7 and PMC identifier 10199078.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Abundant chemical diversity and structural tunability make organic-inorganic hybrid perovskites (OIHPs) a rich ore for ferroelectrics. However, compared with their inorganic counterparts such as BaTiO<sub>3</sub>, their ferroelectric key properties, including large spontaneous polarization (P<sub>s</sub>), low coercive field (E<sub>c</sub>), and strong second harmonic generation (SHG) response, have long been great challenges, which hinder their commercial applications. Here, a quasi-one-dimensional OIHP DMAGeI<sub>3</sub> (DMA = Dimethylamine) is reported, with notable ferroelectric attributes at room temperature: a large P<sub>s</sub> of 24.14 μC/cm<sup>2</sup> (on a par with BaTiO<sub>3</sub>), a low E<sub>c</sub> below 2.2 kV/cm, and the strongest SHG intensity in OIHP family (about 12 times of KH<sub>2</sub>PO<sub>4</sub> (KDP)). Revealed by the first-principles calculations, its large P<sub>s</sub> originates from the synergistic effects of the stereochemically active 4s<sup>2</sup> lone pair of Ge<sup>2+</sup> and the ordering of organic cations, and its low kinetic energy barrier of small DMA cations results in a low E<sub>c</sub>. Our work brings the comprehensive ferroelectric performances of OIHPs to a comparable level with commercial inorganic ferroelectric perovskites.