Zhang Zhuolei, Li Peng-Fei, Tang Yuan-Yuan, Wilson Andrew J, Willets Katherine, Wuttig Manfred, Xiong Ren-Gen, Ren Shenqiang
Department of Mechanical Engineering and Temple Materials Institute, Temple University, Philadelphia, PA 19122, USA.
Ordered Matter Science Research Center, Southeast University, Nanjing 211189, P. R. China.
Sci Adv. 2017 Aug 30;3(8):e1701008. doi: 10.1126/sciadv.1701008. eCollection 2017 Aug.
Recent progress in molecular ferroelectrics (MOFEs) has been overshadowed by the lack of high-quality thin films for device integration. We report a water-based air-processable technique to prepare large-area MOFE thin films, controlled by supersaturation growth at the liquid-air interface under a temperature gradient and external water partial pressure. We used this technique to fabricate ImClO thin films and found a large, tunable room temperature electroresistance: a 20-fold resistance variation upon polarization switching. The as-grown films are transparent and consist of a bamboo-like structure of (2,[Formula: see text],0) and (1,0,[Formula: see text]) structural variants of 3 symmetry with a reversible polarization of 6.7 μC/cm. The resulting ferroelectric domain structure leads to a reversible electromechanical response of = 38.8 pm/V. Polarization switching results in a change of the refractive index, , of single domains, [Formula: see text]. The remarkable combination of these characteristics renders MOFEs a prime candidate material for new nanoelectronic devices. The information that we present in this work will open a new area of MOFE thin-film technologies.
分子铁电体（MOFEs）的近期进展因缺乏用于器件集成的高质量薄膜而黯然失色。我们报道了一种基于水的可在空气中加工的技术，用于制备大面积的MOFE薄膜，该技术通过在温度梯度和外部水蒸气压下的液 - 气界面处的过饱和生长来控制。我们使用该技术制备了ImClO薄膜，并发现了大的、可调节的室温电阻：极化切换时电阻变化20倍。生长的薄膜是透明的，由具有3对称性的（2，[公式：见原文]，0）和（1，0，[公式：见原文]）结构变体的竹状结构组成，可逆极化强度为6.7 μC/cm²。由此产生的铁电畴结构导致可逆机电响应系数为38.8 pm/V。极化切换导致单畴的折射率[公式：见原文]发生变化。这些特性的显著组合使MOFEs成为新型纳米电子器件的主要候选材料。我们在这项工作中展示的信息将开启MOFE薄膜技术的新领域。
