Charge transport in CdTe solar cells revealed by conductive tomographic atomic force microscopy
Charge transport in CdTe solar cells revealed by conductive tomographic atomic force microscopy
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DOI：
10.1038/nenergy.2016.150
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发表时间：
2016-09-26
期刊：
影响因子：
56.7
通讯作者：
Huey, Bryan D.
中科院分区：
文献类型：
--
作者：
Luria, Justin;Kutes, Yasemin;Huey, Bryan D.
碲化镉的微结构缺陷对器件性能的影响在很大程度上仍然未知。这部分是因为表征技术一直无法以纳米级分辨率对贯穿三维晶粒和晶界的电通路进行成像。在这里，我们采用了导电和断层变化的原子力显微镜研究电荷传输在纳米级的功能薄膜太阳能电池与12.3%的效率。通过器件厚度收集的电流图像揭示了空间依赖的短路和开路性能，并证实晶界是电子传输的优先途径。与和没有氯化镉处理的样品上的结果显示在微观尺度上的晶粒结构的差异不大，没有处理的样品几乎没有光电流在平面缺陷或晶界。我们的研究结果支持一个积极的正交传输系统的晶界和互连的平面缺陷，有助于最佳的太阳能电池的性能，相反的传统智慧的有害作用的平面缺陷的多晶薄膜太阳能电池。
The influence of microstructural defects on the device properties in CdTe remains largely unknown. This is partly because characterization techniques have been unable to image electrical pathways throughout three-dimensional grains and grain boundaries with nanoscale resolution. Here, we employ a conductive and tomographic variation of atomic force microscopy to study charge transport at the nanoscale in a functioning thin-film solar cell with 12.3% efficiency. Images of electric current collected through the device thickness reveal spatially dependent short-circuit and open-circuit performance, and confirm that grain boundaries are preferential pathways for electron transport. Results on samples with and without cadmium chloride treatment reveal little difference in grain structure at the microscale, with samples without treatment showing almost no photocurrent either at planar defects or at grain boundaries. Our results supports an energetically orthogonal transport system of grain boundaries and interconnected planar defects as contributing to optimal solar cell performance, contrary to the conventional wisdom of the deleterious role of planar defects on polycrystalline thin-film solar cells.