Eliminating S-Kink To Maximize the Performance of MgZnO/CdTe Solar Cells
Eliminating S-Kink To Maximize the Performance of MgZnO/CdTe Solar Cells
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DOI：
10.1021/acsaem.9b00233
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发表时间：
2019-04-01
影响因子：
6.4
通讯作者：
Yano, Yanfa
中科院分区：
文献类型：
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作者：
Li, Deng-Bing;Song, Zhaoning;Yano, Yanfa
与传统的CdS缓冲层相比，锌镁氧化物（ZMO）为CdTe基薄膜太阳能电池提供了以下优点：它引入了导带偏移尖峰，这减少了有利于增加开路电压（V-OC）的界面复合，并减少了有利于增加短路电流（J（SC））的缓冲层的寄生光吸收。然而，ZMO/CdTe薄膜太阳能电池在其电流-电压曲线中经常显示出所谓的S-扭结行为，使得难以再现预期的益处。在这里，我们表明，S-扭结可以成功地消除，并改善V-OC和J（SC）可以同时实现，如果氯化镉处理过程中进行无氧气氛。结果，器件效率从9.2%提高到16.1%。我们的器件表征和模拟表明，足够高的ZMO缓冲层的电子密度是消除S-扭结的关键，这是通过无氧CdCl 2处理实现的。
Comparing to the traditional CdS buffer layer, zinc magnesium oxide (ZMO) offers the following advantages for CdTe-based thin-film solar cells: it introduces a spike to conduction band offset, which reduces interface recombination that is beneficial for increasing open-circuit voltage (V-OC) and decreases parasitic optical absorption of the buffer layer that is favorable for enhancing short-circuit current (J(SC)). However, ZMO/CdTe thin-film solar cells often show the so-called S-kink behavior in their current-voltage curves, making it difficult to reproduce the expected benefits. Here, we show that S-kink can be successfully eliminated, and improved V-OC and J(SC) can be simultaneously achieved if the CdCl2 treatment process is conducted in oxygen-free atmosphere. As a result, the device efficiencies increased from 9.2% to 16.1%. Our device characterizations and simulations reveal that a sufficiently high electron density of the ZMO buffer layer is critical to eliminate the S-kink, which is achievable through an oxygen-free CdCl2 treatment.