Solvent Engineering Boosts the Efficiency of Paintable Carbon-Based Perovskite Solar Cells to Beyond 14%
Solvent Engineering Boosts the Efficiency of Paintable Carbon-Based Perovskite Solar Cells to Beyond 14%
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DOI：
10.1002/aenm.201502087
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发表时间：
2016-04-20
影响因子：
27.8
通讯作者：
Yang, Shihe
中科院分区：
文献类型：
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作者：
Chen, Haining;Wei, Zhanhua;Yang, Shihe
无碳基空穴传输材料（HTM）的钙钛矿太阳能电池（PSC）由于其高稳定性和低成本而显示出很大的实际应用前景。然而，与有机HTM基PSC相比，这种PSC的效率仍然相对较低，特别是对于最简单的可涂漆碳基PSC。这可以归因于钙钛矿沉积方法不太适合这种器件。采用基于两步序贯法的溶剂工程策略制备可涂覆碳基PSC的高质量钙钛矿层，其中第二步中用于CH 3 NH3 I（MAI）溶液的溶剂由异丙醇（IPA）改变为IPA/环己烷（CYHEX）的混合溶剂。该混合溶剂不仅加速Pbl（2）向CH（3）NH（3）Pbl（3）的转化，而且抑制奥斯特瓦尔德熟化过程，从而产生高质量的钙钛矿层，例如，纯相、表面均匀、包覆层致密。与纯IPA相比，IPA/CYHEX溶剂制备的可涂覆碳基PSC在光伏性能和性能再现性方面表现出显著的提高，尤其是填充因子（FF），这主要是由于钙钛矿/碳界面接触更好，钙钛矿中陷阱密度更低，光吸收能力更高，钙钛矿层的电荷传输速度更快。结果，获得了14.38%的最高功率转换效率（PCE），这是碳基无HTM PSC的记录值。此外，对于大面积器件（1 cm（2）），实现了高达10%的PCE，也是同类产品中最高的。
Carbon-based hole transport material (HTM)-free perovskite solar cells (PSCs) have shown much promise for practical applications because of their high stability and low cost. However, the efficiencies of this kind of PSCs are still relatively low, especially for the simplest paintable carbon-based PSCs, in comparison with the organic HTM-based PSCs. This can be imputed to the perovskite deposition methods that are not very suitable for this kind of devices. A solvent engineering strategy based on two-step sequential method is exploited to prepare a high-quality perovskite layer for the paintable carbon-based PSCs in which the solvent for CH3NH3I (MAI) solution at the second step is changed from isopropanol (IPA) to a mixed solvent of IPA/Cyclohexane (CYHEX). This mixed solvent not only accelerates the conversion of Pbl(2) to CH(3)NH(3)Pbl(3) but also suppresses the Ostwald ripening process resulting in a high-quality perovskite layer, e.g., pure phase, even surface, and compact capping layer. The paintable carbon-based PSCs fabricated from IPA/CYHEX solvent exhibits a considerable enhancement in photovoltaic performance and performance reproducibility in comparison with that from pure IPA, especially on fill factor (FF), owing mainly to the better contact of perovskite/carbon interface, lower trap density in perovskite, higher light absorption ability, and faster charge transport of perovskite layer. As a result, the highest power conversion efficiency (PCE) of 14.38% is obtained, which is a record value for carbon-based HTM-free PSCs. Furthermore, a PCE of as high as 10% is achieved for the large area device (1 cm(2)), also the highest of its kind.