Engineering Elastic Properties of Isostructural Molecular Perovskite Ferroelectrics via B‐Site Substitution

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 17; no. 22; pp. e2006021 - n/a
• Main Authors: An, Lian‐Cai, Li, Kai, Li, Zhi‐Gang, Zhu, Shengli, Li, Qite, Zhang, Zhuo‐Zhen, Ji, Li‐Jun, Li, Wei, Bu, Xian‐He
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.06.2021
• Subjects: Bonding strength; Chemical compounds; Elastic properties; Ferroelectric materials; Ferroelectricity; Ferroelectrics; First principles; high‐pressure behavior; hybrid organic–inorganic perovskites; Hydrogen bonding; metal‐free perovskites; Modulus of elasticity; Nanotechnology; Perovskites; Shear modulus; Synchrotrons; ferroelectrics; metal-free perovskites; hybrid organic-inorganic perovskites; high-pressure behavior; elastic properties
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202006021

Managing elastic properties of ABX3 type molecular perovskite ferroelectrics is critical to their future applications since these parameters determine their service durability and reliability in devices. The abundant structural and chemical viability of these compounds offer a convenient way to manipulate their elastic properties through a facile chemical approach. Here, the elastic properties and high‐pressure behaviors of two isostructural perovskite ferroelectrics, MDABCO‐NH4I3 and MDABCO‐KI3 (MDABCO = N‐methyl‐N′‐diazabicyclo[2.2.2]octonium) is systematically investigated, via the first principles calculations and high‐pressure synchrotron X‐ray diffraction experiments. It is show that the simple replacement of NH4+ by K+ on the B‐site respectively results in up to 48.1%, 52.4%, and 56.3% higher Young's moduli, shear moduli and bulk moduli, which is attributed to the much stronger KI coordination bonding than NH4…I hydrogen bonding. These findings demonstrate that it is possible to tune elastic properties of molecular perovskite ferroelectrics via simply varying the framework assembling interactions. Elastic properties of two isostructural molecular perovskite ferroelectrics are systematically investigated. Strikingly, MDABCO‐KI3 shows much higher moduli than those of MDABCO‐NH4I3 due to the marked different strengths between KI coordination bonds and NH4…I hydrogen interactions. This work demonstrates that it is possible to manage elastic properties of molecular ferroelectrics via facile chemical substitution.