Nature 速遞

2020_Nature_Gram-scale bottom-up flash graphene synthesis

• 擬解決科學問題：石墨烯製備

1. 自上而下：物理法 超聲需大量溶劑和能量

2. 自上而下：化學法 需苛刻的氧化劑並在隨後的還原中留下缺陷

3. 自下而上: 高質量(化學氣相沉積或有機合成) 但是產量小

Bottom-up synthesis of high-quality graphene is often restricted to ultrasmall amounts if performed by chemical vapour deposition or advanced synthetic organic methods, or it provides a defect-ridden structure if carried out in bulk solution

• 材料方法原理及創新點:

1. 用廉價的碳源甚至廢棄的食物,

2. 快速焦耳熱,可在1秒內得到

3. 克級別的石墨烯,具有渦輪狀排序，

4. 無需溶劑和爐子，

5. 產率根據碳源變化，可高達90%，

6. 並且具有高純度,無需純化

7. 低缺陷

8. 低能耗

2020_Nature_Transparent ferroelectric crystals with ultrahigh piezoelectricity

• 擬解決科學問題：

it is challenging to achieve high piezoelectricity and perfect transparency simultaneously because most high-performance piezoelectrics are ferroelectrics that contain high-density light-scattering domain walls.

• 材料方法原理及創新點：

1. 利用交流電場調製疇結構原來不透明的PMN-PT,
2. 得到透明性赫爾高D33 2100 pC/N
3. 機電耦合係數K33 94%
4. 光電係數 220 Pc/V
5. 大籌結構也可實現高D33，顛覆傳統

We find that increasing the domain size leads to a higher d33 value for the [001]-oriented rhombohedral PMN-PT crystals, challenging the conventional wisdom that decreasing the domain size always results in higher piezoelectricity

2020_Nature_Proton-assisted growth of ultra-flat graphene films

• 擬解決科學問題

wrinkles invariably form during CVD growth because of the strong coupling to the substrate, and these limit the large-scale homogeneity of the film

• 材料方法原理及創新點：

質子輔助氣相沉積製備石墨烯，可以在基底上超平鋪展，形成氫鍵，減少褶皺，減小范德華力，形成V型狄拉克錐電子能帶結構，在原子面及深處

2020_Nature_Strain engineering and epitaxial stabilization of halide perovskites

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