First-principles study of the role of strain and hydrogenation on C3N
First-principles study of the role of strain and hydrogenation on C3N
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应变和氢化对C3N作用的第一性原理研究
DOI：
10.1016/j.carbon.2018.03.068
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发表时间：
2018
期刊：
影响因子：
10.9
通讯作者：
Niu Li
中科院分区：
文献类型：
--
作者：
Wang D;an;Bao Yu;Wu Tongshun;Gan Shiyu;Han Dongxue;Niu Li
最近合成的C3N化合物具有独特的物理化学性质。在这项工作中，我们通过第一性原理计算研究了应变对其电子性质和声子性质的影响，以及对锂原子吸附性质的影响。声子色散分析表明，C3N的晶体结构在拉伸应变高达14%时是动态稳定的。计算结果表明，当拉伸应变为0%~12%时，C3N始终是间接带隙半导体，在应变 = 为9%时，带隙达到最大值。而当应变为13%和14%时，C3N变为金属。Li原子倾向于占据C3N表面的C-C六方晶位，扩散势垒为0.43 eV，不同吸附构型的吸附能随应变的增加而增大。此外，声子色散计算和从头算分子动力学模拟表明，C3N，C3NH3的全氢化延伸有两种稳定的构象，一种是间接半导体，禁带宽度为4.09 eV，另一种是直接禁带宽度为2.88 eV，适合光催化应用。具有不同结构和电学性质的应变和氢化C3N为锂离子电池和光电化学的应用提供了新的前景。
C3N has been synthesized recently and demonstrated to possess specific physical and chemical properties. In this work, we investigated the strain effect on it's electronic and phonon properties and on the adsorption property of Li atom through first-principles calculations. Phonon dispersions demonstrate that the crystal structure of C3N is dynamical stable under tensile strain up to 14%. Calculation results show that C3N is always an indirect gap semiconductor as the applied tensile strain is 0%–12% and the band gap reaches its maximum at strain = 9%. While when strain is 13% and 14%, C3N become metallic. Li atom prefers to occupy the C-C hexagonal sites on C3N surface with a diffusion barrier of 0.43eV and the adsorption energies of different adsorption configurations increase with strain. What's more, phonon dispersion calculations and ab initio molecular dynamics simulations reveal that the fully hydrogenated extension of C3N, C3NH3has two stable conformations, in which one is an indirect semiconductor with band gap of 4.09eV while the other possesses a direct band gap of 2.88eV suitable for photocatalytic application. The strained and hydrogenated C3N with diverse structures and electronic properties provide new prospects in the applications of lithium ion batteries and photoelectrochemistry.