Ma Liang, Jia Yinglu, Ducharme Stephen, Wang Jinlan, Zeng Xiao Cheng
Department of Chemistry, Nebraska Center for Materials and Nanoscience , University of Nebraska-Lincoln , Lincoln , Nebraska 68588 , United States.
School of Physics , Southeast University , Nanjing 211189 , China.
J Am Chem Soc. 2019 Jan 30;141(4):1452-1456. doi: 10.1021/jacs.8b12102. Epub 2019 Jan 14.
In light of their easy processing, light weight and mechanical flexibility, ferroelectric molecular crystal with large spontaneous polarization ( P) is highly desired for many advanced applications. Herein, we report the first theoretical study of two-dimensional (2D) ferroelectric molecular crystals via ab initio calculations. Specifically, we show that diisopropylammonium bromide (DIPAB) based 2D ferroelectric monolayer molecular crystal with large in-plane P of ∼1.5 × 10 μC cm can be achieved by slicing the bulk DIPAB along a specific plane while keeping the space group unchanged. The important roles of hydrogen bonds are also identified. Ab initio molecular dynamics simulations indicate that, with the support of a graphene substrate, the ferroelectric order of 2D DIPAB monolayer can be retained at room temperature. Lastly, we show that several other diisopropylammonium halide molecular crystals can also be used to achieve 2D all-organic ferroelectric monolayer singular molecular crystal with large in-plane P.
鉴于其易于加工、重量轻和机械柔韧性，具有大自发极化（P）的铁电分子晶体在许多先进应用中具有很高的需求。在此，我们通过从头算计算报告了二维（2D）铁电分子晶体的首次理论研究。具体而言，我们表明，通过沿特定平面切割块状二异丙基溴化铵（DIPAB）同时保持空间群不变，可以实现具有约1.5×10 μC cm面内大P的基于二异丙基溴化铵（DIPAB）的二维铁电单层分子晶体。还确定了氢键的重要作用。从头算分子动力学模拟表明，在石墨烯衬底的支持下，二维DIPAB单层的铁电有序在室温下可以保留。最后，我们表明，其他几种二异丙基卤化铵分子晶体也可用于实现具有大面内P的二维全有机铁电单层奇异分子晶体。
