Tailoring Electronic and Optical Properties of MXenes through Forming Solid Solutions
Tailoring Electronic and Optical Properties of MXenes through Forming Solid Solutions
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DOI：
10.1021/jacs.0c07395
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发表时间：
2020-11-11
影响因子：
15
通讯作者：
Gogotsi, Yury
中科院分区：
文献类型：
--
作者：
Han, Meikang;Maleski, Kathleen;Gogotsi, Yury
合金化是一种长期采用的策略，可以针对特定应用定制金属的特性，从而保留或增强主要元素特性，同时提供来自添加元素的额外功能。我们提出了一种类似的方法来控制二维过渡金属碳化物（称为MXenes）的性质。MXene（Mn+1Xn）具有两个组成变化位点：金属（M）和碳/氮（X）位点上的元素取代为定制MXene的化学、光学、电子或机械性质提供了有前途的途径。在本文中，我们系统地研究了三种相互关联的二元固溶体MXene系统，其基于M2 XTx结构中M位处的Ti、Nb和/或V（Ti 2-yNbyCTx、Ti 2-yVyCTx和V2-yNbyCTx，其中T-x代表表面终止），显示了电子和光学性质随组成的变化。所有三种MXene系统都显示出无限的溶解度和金属元素在金属亚晶格中的随机分布。在光学上，MXene系统可以以非线性方式进行调整，吸收峰从紫外到近红外波长。固溶体MXene的宏观电导率在室温下可以可控地变化3个数量级，在10 - 300 K范围内可以可控地变化6个数量级。这项工作大大增加了迄今为止报道的非化学计量的MXene的数量，并为通过M位固溶体控制不同MXene的物理性质开辟了途径，这些MXene具有无限数量的组合物。
Alloying is a long-established strategy to tailor properties of metals for specific applications, thus retaining or enhancing the principal elemental characteristics while offering additional functionality from the added elements. We propose a similar approach to the control of properties of two-dimensional transition metal carbides known as MXenes. MXenes (Mn+1Xn) have two sites for compositional variation: elemental substitution on both the metal (M) and carbon/nitrogen (X) sites presents promising routes for tailoring the chemical, optical, electronic, or mechanical properties of MXenes. Herein, we systematically investigated three interrelated binary solid-solution MXene systems based on Ti, Nb, and/or V at the M-site in a M2XTx structure (Ti2-yNbyCTx, Ti2-yVyCTx, and V2-yNbyCTx where T-x stands for surface terminations) showing the evolution of electronic and optical properties as a function of composition. All three MXene systems show unlimited solubility and random distribution of metal elements in the metal sublattice. Optically, the MXene systems are tailorable in a nonlinear fashion, with absorption peaks from ultraviolet to near-infrared wavelength. The macroscopic electrical conductivity of solid solution MXenes can be controllably varied over 3 orders of magnitude at room temperature and 6 orders of magnitude from 10 to 300 K. This work greatly increases the number of nonstoichiometric MXenes reported to date and opens avenues for controlling physical properties of different MXenes with a limitless number of compositions possible through M-site solid solutions.