Constructing heterostructure solar cells using donor and acceptor semiconductors has attracted global interest owing to their high power conversion efficiency. In this paper, based on density functional theory calculations, we comprehensively evaluated 64 two-dimensional transition metal carbides (MXenes) to explore them as appropriate semiconductors for solar cells by material screening. The results highlight that Zr₂CO₂ (Hf₂CO₂) and Ti₂CO₂ are promising donor and acceptor materials, respectively. Interestingly, the heterostructures have a moderate band gap of 1.22 eV and exhibit a noticeable absorbance coefficient of 10⁵ cm⁻¹ in the visible light region. Moreover, the type-II nature of the heterostructures could induce effective electron–hole separation. Furthermore, the photocurrents of Ti₂CO₂/Zr₂CO₂ and Ti₂CO₂/Hf₂CO₂ heterostructure solar cell devices are competitive with those of silicon devices. In particular, Ti₂CO₂/Zr₂CO₂ and Ti₂CO₂/Hf₂CO₂ heterostructure solar cells deliver a very high power conversion efficiency of 22.74% and 19.56%, respectively. Our present study paves the way for facilitating the potential application of MXenes as photovoltaic materials.

中文翻译：

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MXenes：有望用于高效异质结构太阳能电池的供体和受体材料

使用施主和受主半导体构造异质结构太阳能电池由于其高功率转换效率而引起了全球关注。在本文中，基于密度泛函理论计算，我们对64种二维过渡金属碳化物（MXenes）进行了综合评估，以通过材料筛选将其用作太阳能电池的合适半导体。结果表明，Zr ₂ CO ₂（Hf ₂ CO ₂）和Ti ₂ CO ₂分别是有前途的供体和受体材料。有趣的是，异质结构的中带隙为1.22 eV，并且吸光系数显着为10 ⁵ cm ^-1在可见光区域。此外，异质结构的II型性质可以诱导有效的电子-空穴分离。此外，Ti ₂ CO ₂ / Zr ₂ CO ₂和Ti ₂ CO ₂ / Hf ₂ CO ₂异质结构太阳能电池装置的光电流与硅装置相比具有竞争性。特别地，Ti ₂ CO ₂ / Zr ₂ CO ₂和Ti ₂ CO ₂ / Hf ₂ CO ₂异质结构太阳能电池的功率转换效率非常高，分别为22.74％和19.56％。我们目前的研究为促进MXene作为光伏材料的潜在应用铺平了道路。