Constructing van der Waals (vdW) heterojunctions via stacking different two-dimensional materials is an effective approach to obtain desirable properties. By using the first-principles calculation, we explore the vdW heterojunction based on the Janus structure of the 1T-PtTe2 for the potential application in the excitonic solar cell. The SePtTe/InS vdW heterojunction is found to be an appropriate material with direct bandgap, high carrier mobility, high optical absorption, and staggered type-II band alignment. The donor bandgap is 1.08 eV in the Heyd–Scuseria–Ernzerhof (HSE) level. The optoelectronic properties are effectively modulated by both external electric field and vertical strain because inducing the redistribution of charge density in the interlayer. Within the HSE hybrid density functional, the donor bandgap can be tunable up to 1.38 eV. The high power conversion efficiency is tunable to 24.91%, while the flux of absorbed photons keeps beyond 4.41 mA/cm2. Our results indicate the potential application of the SePtTe/InS heterojunction in solar cell utilization.

中文翻译：

---

II型SePtTe/InS范德华异质结的光电特性

通过堆叠不同的二维材料构建范德华 (vdW) 异质结是获得理想特性的有效方法。通过使用第一性原理计算，我们探索了基于 1T-PtTe2 的 Janus 结构的 vdW 异质结在激子太阳能电池中的潜在应用。发现 SePtTe/InS vdW 异质结是一种合适的材料，具有直接带隙、高载流子迁移率、高光吸收和交错的 II 型能带排列。Heyd-Scuseria-Ernzerhof (HSE) 水平的供体带隙为 1.08 eV。由于诱导夹层中电荷密度的重新分布，因此外部电场和垂直应变都有效地调节了光电特性。在 HSE 混合密度泛函中，供体带隙可调至 1.38 eV。高功率转换效率可调至24.91%，同时吸收光子通量保持在4.41 mA/cm2以上。我们的结果表明 SePtTe/InS 异质结在太阳能电池利用中的潜在应用。