Well-Defined Nanostructured, Single Crystalline TiO2 Electron Transport Layer for Efficient Planar Perovskite Solar Cells
Well-Defined Nanostructured, Single Crystalline TiO2 Electron Transport Layer for Efficient Planar Perovskite Solar Cells
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DOI：
10.1021/acsnano.6b01575
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发表时间：
2016-06-01
期刊：
影响因子：
17.1
通讯作者：
Park, Taiho
中科院分区：
文献类型：
--
作者：
Choi, Jongmin;Song, Seulki;Park, Taiho
电子传输层（ETL）在从钙钛矿层提取电子和阻止氟掺杂的氧化锡（FTO）中的电子与钙钛矿层中的空穴之间的复合中起重要作用，特别是在平面钙钛矿太阳能电池中。通过溶液处理旋涂方法（S-TiO 2）制备的致密TiO 2 ETL由于其易于制造而主要用于器件中。在此，我们发现，由于粗糙的FTO表面，包括不规则的膜厚度，不连续的区域，和S-TiO 2和FTO层之间的物理接触差，在S-TiO 2界面处的致命的形态缺陷是不可避免的，并降低了通过平面钙钛矿太阳能电池的电荷传输性能。在这项工作中，使用溅射和阳极氧化产生的TiO 2 ETL的形态缺陷的影响得到缓解。该方法产生了具有优异的透射率、单晶性质、均匀的膜厚度、大的有效面积和与粗糙衬底的无缺陷物理接触的良好限定的纳米结构的TiO 2 ETL，其在平面钙钛矿太阳能电池中提供了出色的电子提取和空穴阻挡。在平面钙钛矿器件中，阳极氧化的TiO 2 ETL（A-TiO 2）与S-TiO 2相比，功率转换效率提高了22%（从12.5%提高到15.2%），稳定的最大功率输出效率提高了44%（从8.9%提高到12.8%）。这项工作突出了ETL几何形状的重要性，最大限度地提高设备性能，并提供了实现理想的ETL形态，弥补了传统的旋涂ETL中观察到的缺点的见解。
An electron transporting layer (ETL) plays an important role in extracting electrons from a perovskite layer and blocking recombination between electrons in the fluorine-doped tin oxide (FTO) and holes in the perovskite layers, especially in planar perovskite solar cells. Dense TiO2 ETLs prepared by a solution processed spin-coating method (S-TiO2) are mainly used in devices due to their ease of fabrication. Herein, we found that fatal morphological defects at the S-TiO2 interface due to a rough FTO surface, including an irregular film thickness, discontinuous areas, and poor physical contact between the S-TiO2 and the FTO layers, were inevitable and lowered the charge transport properties through the planar perovskite solar cells. The effects of the morphological defects were mitigated in this work using a TiO2 ETL produced from sputtering and anodization. This method produced a well-defined nanostructured TiO2 ETL with an excellent transmittance, single-crystalline properties, a uniform film thickness, a large effective area, and defect-free physical contact with a rough substrate that provided outstanding electron extraction and hole blocking in a planar perovskite solar cell. In planar perovskite devices, anodized TiO2 ETL (A-TiO2) increased the power conversion efficiency by 22% (from 12.5 to 15.2%), and the stabilized maximum power output efficiency increased by 44% (from 8.9 to 12.8%) compared with S-TiO2. This work highlights the importance of the ETL geometry for maximizing device performance and provides insights into achieving ideal ETL morphologies that remedy the drawbacks observed in conventional spin-coated ETLs.