The intrinsically poor stability of three-dimensional (3D) α-CsPbI₃ perovskites (PVSKs) greatly hinders their application in solar cells and optoelectronics. Here, we propose a new series of compounds, quasi-2D Dion–Jacobson (DJ) CsPbI₃ PVSKs, through density functional theory (DFT) calculation. The material design is based on periodic intercalation of tailored ethylenediamine cations (EDA²⁺) between the inorganic layers. The resultant quasi-2D (EDA)Cs_n−1Pb_nI_3n+1 PVSKs exhibit fundamentally enhanced stability, owing to the strong I–H interaction of diamine cations with a shortened interlayer distance (∼3.5 Å). Their bandgaps can be widely and linearly tailored from 2.150 (n = 1) to 1.476 eV (n = ∞) with the increase of the inorganic layer number (n). In comparison to the conventional 3D counterparts, they have smaller effective masses, lower exciton energies and larger dielectric constants. Furthermore, the highest power conversion efficiency (PCE) is calculated to be 20.9% (n = 50), evidencing that the quasi-2D DJ CsPbI₃ PVSKs could be an excellent candidate for exciting applications in optoelectronic devices.

中文翻译：

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准二维Dion-Jacobsonα-CsPbI3钙钛矿的有机插层工程

的三维（3D）α-CsPbI固有稳定性差_3个钙钛矿（PVSKs）极大地阻碍它们在太阳能电池和光电子应用。在这里，我们通过密度泛函理论（DFT）计算，提出了一系列新化合物，准2D Dion-Jacobson（DJ）CsPbI ₃ PVSK。材料设计基于在无机层之间定期插入特制的乙二胺阳离子（EDA ²⁺）。所得准2D（EDA）Cs _{n -1} Pb _n I _{3 n +1}由于二胺阳离子与I-H的强相互作用以及缩短的层间距离（约3.5Å），PVSK表现出从根本上增强的稳定性。随着无机层数（n）的增加，它们的带隙可以从2.150（n = 1）到1.476 eV（n =∞）广泛地线性调整。与传统的3D副本相比，它们具有更小的有效质量，更低的激子能量和更大的介电常数。此外，最高功率转换效率（PCE）经计算为20.9％（n = 50），这表明准2D DJ CsPbI ₃ PVSK可能是光电子器件中令人兴奋的应用的极佳候选者。