School of Electronic Engineering, XI'AN University of Posts and Telecommunications, Xi'an 710121, China.
Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
Phys Chem Chem Phys. 2023 Jul 5;25(26):17360-17369. doi: 10.1039/d3cp01290e.
Constructing van der Waals (vdW) heterostructures provides an effective and feasible method for 2D materials to improve their properties and extend their possible applications. Using first-principles calculations, we explored the atomic and electronic structures of Janus InSeX (X = S or Te) and revealed the existence of a vertical internal intrinsic electric field in these Janus monolayers. Then, we stacked the pristine InSe and Janus InSeX (X = S or Te) with black phosphorus (BP) vertically to construct vdW heterostructures with a mismatch of less than 5% and systematically investigated their interface atomic structures and possible applications in photovoltaics. The calculation results reveal that the constructed vdW heterostructures can be synthesized experimentally, and the type-II band alignment can be found in all vdW heterostructures, which is independent of the internal electric field of Janus monolayers, the built-in dipole at the interface between two domains, and the number of layers. In addition, the vdW heterostructures show stronger light absorption compared to monolayer individuals, and the type-II band alignment can help the photo-excited carriers to separate and achieve an excellent photovoltaic power conversion efficiency of up to about 21% in these heterostructures. These extraordinary results suggest that these vdW heterostructures have great potential for more efficient solar photovoltaic applications.
构建范德华（vdW）异质结构为二维材料提供了一种有效且可行的方法，可改善其性能并扩展其可能的应用。我们使用第一性原理计算，研究了 Janus InSeX（X=S 或 Te）的原子和电子结构，并揭示了这些 Janus 单层中存在垂直内部本征电场。然后，我们将原始 InSe 和 Janus InSeX（X=S 或 Te）与黑磷（BP）垂直堆叠，构建层错小于 5%的 vdW 异质结构，并系统研究了它们在光伏中的界面原子结构和潜在应用。计算结果表明，所构建的 vdW 异质结构可以通过实验合成，所有 vdW 异质结构中都可以找到 II 型能带排列，这与 Janus 单层的内电场、两个畴之间界面的内置偶极子以及层数无关。此外，与单层个体相比，vdW 异质结构表现出更强的光吸收，II 型能带排列有助于光激发载流子分离，并在这些异质结构中实现高达约 21%的优异光伏功率转换效率。这些非凡的结果表明，这些 vdW 异质结构在更高效的太阳能光伏应用中具有巨大的潜力。
