The Limited Relevance of SWE Dangling Bonds to Degradation in High-Quality a-Si:H Solar Cells
The Limited Relevance of SWE Dangling Bonds to Degradation in High-Quality a-Si:H Solar Cells
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SWE 悬挂键与高质量 a-Si:H 太阳能电池退化的有限相关性
DOI：
10.1109/jphotov.2014.2311498
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发表时间：
2014
影响因子：
3
通讯作者：
X. Niu
中科院分区：
文献类型：
--
作者：
C. Wronski;X. Niu
对于i层原晶a-Si：H以很低的速率沉积的高质量p-i-n太阳电池，建立了不同的光致缺陷态对太阳电池退化的贡献，其纳米结构以氢钝化双空位为主。从薄膜的光电流和相应的太阳电池的Shockley-Reed-Hall载流子复合电流表征了不同光致能带态的性质及其作为电子和空穴复合中心的作用。实验结果与三个光致发光态直接相关，根据亚能隙吸收，“A”和“B”在0.2 eV以内，而“C”在0.4 eV以下。A态和B态是有效电子，而C态是非常有效的空穴复合中心。在1太阳光照下，前者主导电子寿命，而后者是太阳能电池运行的关键，其产生与VOC和1太阳填充因子(Ff)的退化直接相关。结果还表明，早先发现的电池Ff和电子寿命之间的明显相关性是由于光诱导的B、t和C态变化的相同的长期退化动力学。
Contributions of different light-induced defect states to degradation of solar cells have been established for high-quality p-i-n solar cells with i layers of protocrystalline a-Si:H deposited at very low rates, whose nanostructure is dominated by hydrogen-passivated divacancies. Nature of the different light-induced gap states and their respective roles as electron and hole recombination centers were characterized in the thin films from their photocurrents, and in corresponding solar cells from their Shockley-Reed-Hall carrier recombination currents. The results were directly related to three light-induced states, with “A” and “B” within 0.2 eV and “C” 0.4 eV below midgap, identified from subgap absorption. The A and B states are efficient electron, while the C states are very efficient hole recombination centers. Under 1-sun illumination, the former dominate the electron lifetimes, while the latter are key to solar cell operation as is confirmed by the direct correlation of their creation with the degradation of VOC and 1-sun fill factor (FF). It is also shown that the apparent correlation found earlier between the cell FF and electron lifetimes is due to the same long-term degradation kinetics of the light-induced changes in the B t and C states.