Sun Muhua, Stolte Nore, Wang Jianlin, Wei Jiake, Chen Pan, Xu Zhi, Wang Wenlong, Pan Ding, Bai Xuedong
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
Department of Physics, Hong Kong University of Science and Technology, Hong Kong, 999077, China.
Small. 2021 Aug;17(32):e2101641. doi: 10.1002/smll.202101641. Epub 2021 Jul 1.
As the lightest solid element and also the simplest metal, lithium (Li) is one of the best representations of quasi-free electron model in both bulk form and the reduced dimensions. Herein, the controlled growth of 2D ultrathin Li nanosheets is demonstrated by utilizing an in situ electrochemical platform built inside transmission electron microscope (TEM). The as-grown freestanding 2D Li nanosheets have strong structure-anisotropy with large lateral dimensions up to several hundreds of nanometers and thickness limited to just a few nanometers. The nanoscale dynamics of nanosheets growth are unraveled by in situ TEM imaging in real-time. Further density-functional theory calculations indicate that oxygen molecules play an important role in directing the anisotropic 2D growth of Li nanosheets through controlling the growth kinetics by their facet-specific capping. The plasmonic optical properties of the as-grown Li nanosheets are probed by cathodoluminescence spectroscopy equipped within TEM, and a broadband visible emission is observed that contains contributions of both in-plane and out-of-plane plasmon resonance modes.
作为最轻的固体元素以及最简单的金属，锂（Li）无论是在块状形式还是在低维形式下，都是准自由电子模型的最佳代表之一。在此，通过利用透射电子显微镜（TEM）内部构建的原位电化学平台，展示了二维超薄锂纳米片的可控生长。所生长的独立二维锂纳米片具有很强的结构各向异性，横向尺寸可达数百纳米，而厚度仅限制在几纳米。通过原位TEM实时成像揭示了纳米片生长的纳米级动力学。进一步的密度泛函理论计算表明，氧分子通过其特定晶面封端控制生长动力学，在引导锂纳米片的各向异性二维生长中起着重要作用。通过TEM配备的阴极发光光谱探测所生长的锂纳米片的等离子体光学性质，观察到宽带可见发射，其中包含面内和面外等离子体共振模式的贡献。
