Analysis of laser scribes at CIGS thin-film solar cells by localized electrical and optical measurements
Analysis of laser scribes at CIGS thin-film solar cells by localized electrical and optical measurements
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DOI：
10.1016/j.optlastec.2012.01.009
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发表时间：
2012-09
影响因子：
5
通讯作者：
A. Wehrmann;S. Puttnins;Lars Hartmann;M. Ehrhardt;P. Lorenz;K. Zimmer
中科院分区：
文献类型：
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作者：
A. Wehrmann;S. Puttnins;Lars Hartmann;M. Ehrhardt;P. Lorenz;K. Zimmer
薄膜太阳能电池的激光图案化是实现组件应用的外部串联和集成单片互连所必需的，近年来受到越来越多的关注。然而，目前的研究表明，由于超短激光脉冲的激光划片，薄膜Cu(In，Ga)Se2(CIGS)组件的效率降低。因此，为了研究激光诱导材料改性的原因，用飞秒和皮秒激光脉冲对薄膜CIGS太阳电池进行了激光刻划，采用不同的刻划程序和激光加工参数。除了标准的电流电压(I-V)测量外，还进行了其他的电学和光学分析，如激光感应电流(LBIC)、暗锁定热成像(DLIT)和电致发光(EL)测量，以表征和定位由于划线板上的材料移除/修改而导致的影响太阳能电池性能的电损耗。激光划线边缘既有局部分流，也有分布分流，但激光光斑强度分布影响分流的形成。低于TCO薄膜烧蚀阈值的激光辐照已经引起薄膜太阳电池叠层内部的材料修饰，导致TCO/CIGS界面附近的材料熔化而形成分流，这可能导致pn结的损伤。
Laser patterning of thin-film solar cells is essential to perform external serial and integrated monolithic interconnections for module application and has recently received increasing attention. Current investigations show, however, that the efficiency of thin-film Cu(In,Ga)Se2(CIGS) modules is reduced due to laser scribing also with ultrashort laser pulses. Hence, to investigate the reasons of the laser-induced material modifications, thin-film CIGS solar cells were laser-scribed with femto- and picosecond laser pulses using different scribing procedures and laser processing parameters. Besides standard electrical current voltage (I–V) measurements, additional electrical and optical analysis were performed such as laser beam-induced current (LBIC), dark lock-in thermography (DLIT), and electroluminescence (EL) measurements to characterize and localize electrical losses due to material removal/modifications at the scribes that effecting the electrical solar cell properties. Both localized as well as distributed shunts were found at laser scribe edges whereas the laser spot intensity distribution affecting the shunt formation. Already laser irradiation below the ablation threshold of the TCO film causes material modification inside the thin film solar cell stack resulting in shunt formation as a result of materials melting near the TCO/CIGS interface that probably induces the damage of the pn-junction.