Crystallization Kinetics and Morphology Control of Formamidinium-Cesium Mixed-Cation Lead Mixed-Halide Perovskite via Tunability of the Colloidal Precursor Solution
Crystallization Kinetics and Morphology Control of Formamidinium-Cesium Mixed-Cation Lead Mixed-Halide Perovskite via Tunability of the Colloidal Precursor Solution
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DOI：
10.1002/adma.201607039
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发表时间：
2017-08-04
影响因子：
29.4
通讯作者：
Snaith, Henry J.
中科院分区：
文献类型：
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作者：
McMeekin, David P.;Wang, Zhiping;Snaith, Henry J.
钙钛矿太阳能电池领域的迅速崛起得益于通过简单的溶液加工方法可以轻松制造各种高质量材料。然而，迄今为止，很少有人致力于了解前体溶液，以及添加剂如氢卤酸对薄膜结晶和最终光电质量的作用。在此，建立了[HC（NH 2）（2）]（0.83）Cs0.17Pb（Br0.2I0.8）（3）前体溶液中存在的胶体浓度与薄膜形成的成核和生长阶段之间的直接联系。使用动态光散射分析，监测由添加氢卤酸引发的胶体在一段时间内的溶解。这些胶体似乎为钙钛矿结晶提供了成核位点，这对形态、晶体质量和光电性能产生了重要影响。通过2D X射线衍射，观察到从具有较低胶体浓度的溶液制备的膜的高度有序和织构化的晶体。这种材料质量的提高使得微应变沿着降低，同时电荷载流子迁移率增加两倍，导致值超过20 cm（2）V-1 s（-1）。使用具有优化的胶体浓度的溶液，制造了达到18.8%的电流-电压测量功率转换效率和17.9%的稳定效率的器件。
The meteoric rise of the field of perovskite solar cells has been fueled by the ease with which a wide range of high-quality materials can be fabricated via simple solution processing methods. However, to date, little effort has been devoted to understanding the precursor solutions, and the role of additives such as hydrohalic acids upon film crystallization and final optoelectronic quality. Here, a direct link between the colloids concentration present in the [HC(NH2)(2)](0.83)Cs0.17Pb(Br0.2I0.8)(3) precursor solution and the nucleation and growth stages of the thin film formation is established. Using dynamic light scattering analysis, the dissolution of colloids over a time span triggered by the addition of hydrohalic acids is monitored. These colloids appear to provide nucleation sites for the perovskite crystallization, which critically impacts morphology, crystal quality, and optoelectronic properties. Via 2D X-ray diffraction, highly ordered and textured crystals for films prepared from solutions with lower colloidal concentrations are observed. This increase in material quality allows for a reduction in microstrain along with a twofold increase in charge-carrier mobilities leading to values exceeding 20 cm(2) V-1 s(-1). Using a solution with an optimized colloidal concentration, devices that reach current-voltage measured power conversion efficiency of 18.8% and stabilized efficiency of 17.9% are fabricated.