材料科学
单层
压电
电场
极化(电化学)
范德瓦尔斯力
铁电性
纳米发生器
凝聚态物理
光电子学
纳米技术
价(化学)
压电系数
化学物理
复合材料
物理
电介质
物理化学
量子力学
有机化学
化学
分子
出处
期刊:Nano Energy
[Elsevier]
日期:2021-05-01
卷期号:83: 105786-105786
被引量:8
标识
DOI:10.1016/j.nanoen.2021.105786
摘要
For the recently emerging two-dimensional van der Waals ferroelectrics, their promising prospects in nanoelectronic applications are hindered by their low vertical polarizations. Despite recent experimental breakthroughs and theoretical high throughput screening of material database, the obtained vertical polarizations of two-dimensional ferroelectrics are still limited. Here we propose a strategy of constructing two-dimensional mixed-valence compounds. We show first-principles evidence that Sn2S3 monolayer can be synthesized via epitaxial growth of SnS on SnS2 monolayer with degenerate mixed-valence bi-states. Such a system possesses a room-temperature robust vertical polarization higher than 10 pC/m, which can be switched via interchange of oxidation states between two layers crossing an energy-saving low barrier, either by applying an electric field or mechanical bending. If such Sn2S3 monolayer is utilized as a nanogenerator, an unprecedented alternating voltage of ~130 V can be generated by applying an oscillating driving force that repeatedly reverses its polarization. Moreover, it possesses multiple metastable phases with distinct electronic properties. The transformations between them are not only strain-tunable, but can also be controlled via external electric field or low frequency linearly polarized light. Due to the small energy difference between polar and nonpolar states with distinct thicknesses, akin to morphotoropic phases, an ultra-high piezoelectric coefficient (> 2700 pm/V) can be obtained in the phase transformation under pressure, which can be further greatly enhanced via critical doping.
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