Ligand-Stabilized Reduced-Dimensionality Perovskites
Ligand-Stabilized Reduced-Dimensionality Perovskites
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DOI：
10.1021/jacs.5b11740
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发表时间：
2016-03-02
影响因子：
15
通讯作者：
Sargent, Edward H.
中科院分区：
文献类型：
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作者：
Quan, Li Na;Yuan, Mingjian;Sargent, Edward H.
金属卤化物钙钛矿具有快速发展的薄膜光伏性能;因此，观察到的材料不稳定性迫切需要解决方案。使用密度泛函理论（DFT），我们表明，低能量的形成，在湿度的存在下加剧，解释了钙钛矿分解回其前体的倾向。我们发现，也使用DFT，钙钛矿层之间的插层苯乙胺引入定量可观的货车德瓦尔斯相互作用。这些驱动增加的地层能量，因此应改善材料稳定性。在这里，我们报告了降维（准2D）钙钛矿薄膜，其表现出更好的稳定性，同时保留了传统三维钙钛矿的高性能。通过材料合成中化学计量的选择，实现了使用物理学研究评估的维度的连续调整。我们在平面钙钛矿太阳能电池中实现了第一个经过认证的无钙钛矿太阳能转换，获得了15.3%的认证PCE，并观察到大大提高的性能寿命。
Metal halide perovskites have rapidly advanced thin-film photovoltaic performance; as a result, the materials observed instabilities urgently require a solution. Using density functional theory (DFT), we show that a low energy of formation, exacerbated in the presence of humidity, explains the propensity of perovskites to decompose back into their precursors. We find, also using DFT, that intercalation of phenylethylammonium between perovskite layers introduces quantitatively appreciable van der Waals interactions. These drive an increased formation energy and should therefore improve material stability. Here we report reduced-dimensionality (quasi-2D) perovskite films that exhibit improved stability while retaining the high performance of conventional three-dimensional perovskites. Continuous tuning of the dimensionality, as assessed using photophysical studies, is achieved by the choice of stoichiometry in materials synthesis. We achieve the first certified hysteresis-free solar power conversion in a planar perovskite solar cell, obtaining a 15.3% certified PCE, and observe greatly improved performance longevity.