School of Science, Jimei University, Xiamen, 361021, China.
Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
Phys Chem Chem Phys. 2023 May 31;25(21):15052-15061. doi: 10.1039/d3cp00484h.
Structure engineering presents unique opportunities in materials science field, including material design and modification. Herein, we applied structure engineering to double-sublayer hexagonal CP monolayers so as to form two novel non-Janus structures and two new Janus structures. Based on first-principles calculations, the stability, electronic, optical, and photocatalytic properties of the CP monolayers, including the two discovered structures and four new CP monolayers, have been investigated. The results showed that these CP monolayers are highly stable in energetics, dynamics, and thermodynamics. We also found that counterrotating 60° between the top and bottom sublayers could make the CP monolayers become more stable. The calculations of the project band structures indicated that the new CP monolayers were semiconductors with indirect band gaps ranging from 1.02 eV to 2.62 eV. Meanwhile, it was also suggested that the distributions of VBM and CBM in the two Janus CP monolayers were out-of-plane due to their internal electric fields. Moreover, the carrier mobility of the CP monolayers was anisotropic between an armchair and zigzag direction and quite high (reaching 10 cm V s) in the zigzag direction. Additionally, all the CP monolayers had large exciton binding energies (∼1.0 eV) and considerable absorption in the visible-light region. Furthermore, except for the CP-3 monolayer, all the CP monolayers, including CP-1, CP-2, CP-4, CP-5, and CP-6, have great potential for metal-free visible-light photocatalytic water splitting. Our calculations reveal that structure engineering is particularly applicable to multi-sublayer two-dimensional materials for discovering new members and tuning their properties.
结构工程在材料科学领域提供了独特的机会，包括材料设计和改性。在此，我们将结构工程应用于双层六方 CP 单层，以形成两种新型非 Janus 结构和两种新型 Janus 结构。基于第一性原理计算，研究了 CP 单层（包括两种发现的结构和四种新的 CP 单层）的稳定性、电子、光学和光催化性能。结果表明，这些 CP 单层在能量、动力学和热力学上都非常稳定。我们还发现，上下子层之间反旋转 60°可以使 CP 单层更加稳定。能带结构的计算表明，新的 CP 单层是半导体，具有从 1.02eV 到 2.62eV 的间接带隙。同时，还表明两个 Janus CP 单层的 VBM 和 CBM 分布由于内部电场而不在平面内。此外，CP 单层的载流子迁移率在扶手椅和锯齿方向之间具有各向异性，在锯齿方向上相当高（达到 10cmV s）。此外，所有 CP 单层都具有较大的激子结合能（~1.0eV）和在可见光区的可观吸收。此外，除 CP-3 单层外，所有 CP 单层，包括 CP-1、CP-2、CP-4、CP-5 和 CP-6，都具有用于无金属可见光光催化水分解的巨大潜力。我们的计算表明，结构工程特别适用于多层二维材料，用于发现新成员和调整其性质。
