The organic–inorganic hybrid quasi-two-dimensional (quasi-2D) perovskites have attracted increasing attention for solar cell applications due to their improved moisture stability and excellent optoelectronic properties. To achieve a profound understanding and delicate control on the component of perovskite, it is indispensable to know how different spacer cations affect their intrinsic properties. Here, we synthesized a series of quasi-2D perovskite single crystals with different organic spacer cations and conducted a systematic investigation to correlate the optoelectronic behaviors to the spacer cations. We revealed the coupling effect between the π-electron (PEA⁺) and p orbital of I^– from the inorganic framework, which changed the electronic configuration of resultant crystals leading to different band gap and carrier behavior. In particular, the anisotropic carrier mobility was probed quantitatively by space-charge limited current (SCLC) measurement, where PEA₂MA₂Pb₃I₁₀ exhibited the highest in-plane mobility due to the reduced exciton binding energy and the lowest out-of-plane mobility because of the widest organic barrier.

中文翻译：

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具有可变间隔阳离子的准2D钙钛矿单晶的电子可调性和迁移率各向异性。

有机-无机杂化准二维（准2D）钙钛矿因其改善的水分稳定性和出色的光电性能而吸引了越来越多的关注，用于太阳能电池。为了深刻理解钙钛矿的成分并对其进行精细控制，必须知道不同的间隔物阳离子如何影响其固有性质。在这里，我们合成了一系列具有不同有机间隔基阳离子的准2D钙钛矿单晶，并进行了系统的研究，以使光电行为与间隔基阳离子相关。我们揭示了I ^–的π电子（PEA ⁺）与p轨道之间的耦合效应。无机骨架，改变了最终晶体的电子结构，导致不同的带隙和载流子行为。特别是，各向异性载流子迁移率是通过空间电荷限制电流（SCLC）测量进行定量探测的，其中PEA ₂ MA ₂ Pb ₃ I ₁₀由于激子结合能的降低和最低的外向迁移率而具有最高的面内迁移率。平面移动性是由于最宽的有机屏障。