Charge Transport Affected by Energy Level Alignment in Perovskite Solar Cells
Charge Transport Affected by Energy Level Alignment in Perovskite Solar Cells
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DOI：
10.1063/5.0073635
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发表时间：
2021-11
影响因子：
2.5
通讯作者：
Qiqi Zhang;Kira Williams;J. Tatum;F. Han;Xianchun Zhu;Qilin Dai
中科院分区：
文献类型：
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作者：
Qiqi Zhang;Kira Williams;J. Tatum;F. Han;Xianchun Zhu;Qilin Dai
在钙钛矿太阳能电池中，电子传输层对器件性能非常关键。在这项工作中，我们使用溶液处理的方法来制备均匀的Zn2SnO4，SnO2和ZnO薄膜，使用非常相似的实验条件。制备并比较了基于不同电子传输层的超导太阳能电池。三个不同的能级排列所产生的Zn2SnO4，SnO2，和ZnO的实现相应的带隙结构。同时，三种材料引起的能量损失和驱动力是影响电荷输运的两个重要因素。我们使用这个系统来测试哪个因素是占主导地位的电荷传输和器件性能。基于Zn2SnO4的PSC的最佳效率为16.9%，远高于通过类似方法制备的SnO2（13.4%）和ZnO（5.9%）。因此，我们将高效率归因于从钙钛矿层到Zn2SnO4的电荷转移期间的能量损失减少。基于SnO2和ZnO的PSC的大驱动力不能实现高效率。因此，在存在驱动力的情况下，能量损失是主导因素。这项工作提出了一个理解的有效的电荷转移在器件中，这提出了一个方向，以优化电荷转移在光电器件朝着高效率。
The electron transport layer is very critical to the device performance in perovskite solar cells. In this work, we use a solution-processed method to prepare uniform Zn2SnO4, SnO2, and ZnO thin films using very similar experimental conditions. Perovskite solar cells (PSCs) based on different electron transporting layers are fabricated and compared. Three different energy level alignments produced by Zn2SnO4, SnO2, and ZnO are realized by the corresponding bandgap structures. Meanwhile, energy loss and driving force caused by the three materials are two important factors that affect charge transport. We use this system to test which factor is dominant in terms of charge transport and device performance. The optimal efficiency of PSCs based on Zn2SnO4 is 16.9%, which is much higher than SnO2 (13.4%) and ZnO (5.9%) prepared by a similar method. Therefore, we attribute the high efficiency to the reduced energy loss during charge transfer from the perovskite layer to Zn2SnO4. The large driving force of the PSC based on SnO2 and ZnO cannot achieve high efficiency. Therefore, energy loss is a dominant factor in the presence of a driving force. This work presents an understanding of the efficient charge transfer in the devices, which proposes a direction to optimize charge transfer in optoelectronic devices toward high efficiency.