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Tunable Structural, Electronic, and Optical Properties of Layered Two-Dimensional C2N and MoS2 van der Waals Heterostructure as Photovoltaic Material

Guan, Zhaoyong, Lian, Chao-Sheng, Hu, Shuanglin, Ni, Shuang, Li, Jia, Duan, Wenhui
The Journal of Physical Chemistry C 2017 v.121 no.6 pp. 3654-3660
absorption, electrons, optical properties, photovoltaic cells, solar energy, van der Waals forces
The nitrogenated porous two-dimensional (2D) material C₂N has been successfully synthesized using a simple wet-chemical reaction, which provides a high-performance way to produce such 2D materials with novel electronic and optical properties. In this work, density functional theory (DFT) calculations were performed to investigate the structural, electronic, and optical properties of the layered C₂N/MoS₂ van der Waals (vdW) heterojunction. The C₂N/MoS₂ heterojunction was found to have a direct band gap of 1.30 eV and to present the typical type-II heterojunction feature, facilitating the effective separation of photogenerated electrons and holes. The calculated band alignment and enhanced optical absorption suggest that the C₂N/MoS₂ heterojunction should exhibit good light-harvesting properties. The vertical strain can effectively tune the electronic properties and optical absorption of the C₂N/MoS₂ heterojunction by changing the interaction between the pz orbital of C₂N and the dz₂ orbital of MoS₂. The moderate band gap, well-separated photogenerated electrons and holes, and enhanced visible-light absorption indicate that the C₂N/MoS₂ heterojunction is a potential photovoltaic structure for solar energy.