Electronic properties of Cu(In,Ga)Se2 solar cells on stainless steel foils without diffusion barrier
Electronic properties of Cu(In,Ga)Se2 solar cells on stainless steel foils without diffusion barrier
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DOI：
10.1002/pip.1247
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发表时间：
2012-05
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通讯作者：
F. Pianezzi;A. Chirilă;P. Blösch;S. Seyrling;S. Buecheler;L. Kranz;C. Fella;A. N. Tiwari
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作者：
F. Pianezzi;A. Chirilă;P. Blösch;S. Seyrling;S. Buecheler;L. Kranz;C. Fella;A. N. Tiwari
与刚性玻璃相比，在柔性不锈钢（SS）基板上制造Cu（In，Ga）Se2（CIGS）太阳能电池具有降低生产成本的潜力，因为采用了卷对卷工艺。到目前为止，只有当基板涂覆有阻挡层（例如SiOx或Si3N4）以阻止杂质（特别是Fe）扩散到CIGS层中时，才能在SS上实现高效电池。在本文中，这些杂质对器件的电子输运特性的影响进行了研究。使用导纳谱，观察到在约320 meV的深缺陷能级的存在，这恶化了太阳能电池的效率。此外，它示出，在CIGS沉积过程中降低衬底温度是一个有效的替代阻挡层，用于减少有害的Fe杂质扩散到吸收层。通过在低衬底温度下应用CIGS生长工艺进行沉积，在没有额外的金属氧化物或金属氮化物杂质扩散阻挡层的情况下，在Mo/Ti涂覆的SS衬底上实现了17.7%的效率（由弗劳恩霍夫研究所ISE，弗赖堡认证）。版权所有© 2012约翰威利父子有限公司.
Compared with rigid glass, manufacturing of Cu(In,Ga)Se2 (CIGS) solar cells on flexible stainless steel (SS) substrates has potential to reduce production cost because of the application of roll‐to‐roll processing. Up to now, high‐efficiency cells on SS could only be achieved when the substrate is coated with a barrier layer (e.g. SiOx or Si3N4) for hindering the diffusion of impurities, especially Fe, into the CIGS layer. In this paper, the effect of these impurities on the electronic transport properties of the device is investigated. Using admittance spectroscopy, the presence of a deep defect level at around 320 meV is observed, which deteriorates the efficiency of the solar cells. Furthermore, it is shown that reducing substrate temperature during CIGS deposition is an effective alternative to a barrier layer for reducing diffusion of detrimental Fe impurities into the absorber layer. By applying a CIGS growth process for deposition at low substrate temperatures, an efficiency of 17.7%, certified by Fraunhofer Institute ISE, Freiburg, was achieved on Mo/Ti‐coated SS substrate without an additional metal‐oxide or metal‐nitride impurity diffusion barrier layer. Copyright © 2012 John Wiley & Sons, Ltd.