Center for Physical Sciences and Technology, Savanoriu Ave. 231, LT-02300, Vilnius, Lithuania.
Laboratory for Thin Films and Photovoltaics, Swiss Federal Laboratories for Materials Science and Technology EMPA, Ueberlandstrasse 129, CH-8600 Duebendorf, Switzerland.
Sci Rep. 2017 Jan 13;7:40502. doi: 10.1038/srep40502.
In this paper, we investigate the laser processing of the CIGS thin-film solar cells in the case of the high-speed regime. The modern ultra-short pulsed laser was used exhibiting the pulse repetition rate of 1 MHz. Two main P3 scribing approaches were investigated - ablation of the full layer stack to expose the molybdenum back-contact, and removal of the front-contact only. The scribe quality was evaluated by SEM together with EDS spectrometer followed by electrical measurements. We also modelled the electrical behavior of a device at the mini-module scale taking into account the laser-induced damage. We demonstrated, that high-speed process at high laser pulse repetition rate induced thermal damage to the cell. However, the top-contact layer lift-off processing enabled us to reach 1.7 m/s scribing speed with a minimal device degradation. Also, we demonstrated the P3 processing in the ultra-high speed regime, where the scribing speed of 50 m/s was obtained. Finally, selected laser processes were tested in the case of mini-module scribing. Overall, we conclude, that the top-contact layer lift-off processing is the only reliable solution for high-speed P3 laser scribing, which can be implemented in the future terawatt-scale photovoltaic production facilities.
本文研究了在高速条件下 CIGS 薄膜太阳能电池的激光加工。使用了现代超短脉冲激光器，其脉冲重复率为 1MHz。研究了两种主要的 P3 划线方法——完全层叠的烧蚀以暴露钼背接触，以及仅去除前接触。通过 SEM 以及 EDS 光谱仪进行划线质量评估，随后进行电测量。我们还考虑激光诱导损伤，对器件在微型模块尺度上的电行为进行建模。我们证明，在高激光脉冲重复率下的高速过程会对电池造成热损伤。然而，顶接触层的剥离处理使我们能够以最小的器件退化达到 1.7m/s 的划线速度。此外，我们还在超高速度下进行了 P3 处理，获得了 50m/s 的划线速度。最后，在微型模块划线的情况下测试了选定的激光工艺。总的来说，我们得出结论，顶接触层剥离处理是高速 P3 激光划线的唯一可靠解决方案，可在未来的太瓦级光伏生产设施中实施。
