Recently, layered halide double perovskites (A₄M^IM^IIIX₈) have attracted growing interest and provided a wide range of basic building blocks for fabricating vertical and lateral heterostructures (LHs). Here, we take Cs₄AgInI₈ and Cs₄CuBiI₈ as the representative compounds of monolayer double perovskites to design suitable LHs for optoelectronic applications using first-principles calculations. Our results reveal that the constructed (Cs₄CuBiI₈)₃/(Cs₄AgInI₈)₃ LH could possess the desired direct band gap and type-II band alignment. The electronic properties such as band gap and effective mass can be further tuned by applying strain or adjusting components. More importantly, we find that the transition dipole moments between the band edges can be modulated effectively by tensile strain and components, providing new insights for the rational utilization of double perovskites that possess partially forbidden transitions for optoelectronic devices. Our studies propose stable atomic structures for optoelectronic devices based on double perovskite LHs with desired electronic and optical properties.

中文翻译：

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用于光电应用的单层卤化物双钙钛矿的II型横向异质结构

最近，层状卤化物双钙钛矿（A ₄ M ^I M ^III X ₈）引起了越来越多的兴趣，并为制造垂直和横向异质结构（LHs）提供了广泛的基础构件。在这里，我们以Cs ₄ AgInI ₈和Cs ₄ CuBiI ₈为单层双层钙钛矿的代表化合物，以使用第一性原理计算设计适用于光电应用的LH。我们的结果表明，构建的（Cs ₄ CuBiI ₈）₃ /（Cs ₄ AgInI ₈）₃LH可能具有所需的直接带隙和II型带对准。诸如带隙和有效质量之类的电子特性可以通过施加应变或调节成分来进一步调整。更重要的是，我们发现带边缘之间的跃迁偶极矩可以通过拉伸应变和分量有效地进行调制，从而为合理利用具有部分禁止跃迁的光电二极管双钙钛矿提供了新的见解。我们的研究提出了基于具有所需电子和光学性能的双钙钛矿型LHs的光电器件的稳定原子结构。