Department of Chemical Engineering, University of Virginia, Charlottesville, VA, 22904, USA.
Department of Physics, University of Virginia, Charlottesville, VA, 22904, USA.
Nat Commun. 2018 Apr 6;9(1):1336. doi: 10.1038/s41467-018-03757-0.
Thin films based on two-dimensional metal halide perovskites have achieved exceptional performance and stability in numerous optoelectronic device applications. Simple solution processing of the 2D perovskite provides opportunities for manufacturing devices at drastically lower cost compared to current commercial technologies. A key to high device performance is to align the 2D perovskite layers, during the solution processing, vertical to the electrodes to achieve efficient charge transport. However, it is yet to be understood how the counter-intuitive vertical orientations of 2D perovskite layers on substrates can be obtained. Here we report a formation mechanism of such vertically orientated 2D perovskite in which the nucleation and growth arise from the liquid-air interface. As a consequence, choice of substrates can be liberal from polymers to metal oxides depending on targeted application. We also demonstrate control over the degree of preferential orientation of the 2D perovskite layers and its drastic impact on device performance.
基于二维金属卤化物钙钛矿的薄膜在众多光电设备应用中展现出了非凡的性能和稳定性。与当前的商业技术相比，二维钙钛矿的简单溶液处理为以更低的成本制造设备提供了机会。实现器件高性能的关键在于在溶液处理过程中使二维钙钛矿层垂直于电极排列，以实现有效的电荷传输。然而，目前还不清楚如何获得二维钙钛矿层在衬底上这种违背直觉的垂直取向。在这里，我们报告了一种这样的垂直取向二维钙钛矿的形成机制，其中成核和生长源于液-气界面。因此，根据目标应用，衬底的选择可以从聚合物扩展到金属氧化物。我们还证明了对二维钙钛矿层的优先取向程度的控制及其对器件性能的巨大影响。
