Fernandez Beatriz, Lobo Lara, Reininghaus Nies, Pereiro Rosario, Sanz-Medel Alfredo
Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Clavería, 8, 33006 Oviedo, Spain.
Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Clavería, 8, 33006 Oviedo, Spain.
Talanta. 2017 Apr 1;165:289-296. doi: 10.1016/j.talanta.2016.12.062. Epub 2016 Dec 25.
Beside low production costs and the use of nontoxic and abundant raw materials, silicon based thin-film solar cells have the advantage to be built up as multi junction devices like tandem or triple junction solar cells. Silicon thin film modules made of tandem cells with hydrogenated amorphous silicon (a-Si:H) top cell and microcrystalline (μc) Si:H bottom cell are available on the market. In this work, the analytical potential of state-of-the art radiofrequency (rf) pulsed glow discharge (PGD) time of flight mass spectrometry (TOFMS) commercial instrumentation is investigated for depth profiling analysis of tandem-junctions solar cells on 2mm thick glass substrate with 1µm thick ZnO:Al. Depth profile characterization of two thin film tandem photovoltaic devices was compared using millisecond and sub-millisecond rf-PGD regimes, as well as the so-called "low mass mode" available in the commercial instrument used. Two procedures for sample preparation, namely using flat or rough cell substrates, were compared and the distribution of dopant elements (phosphorous, boron and germanium) was investigated in both cases. Experimental results obtained by rf-PGD-TOFMS as well as electrical measurements of the samples showed that a worse depth resolution of dopant elements in the silicon layers (e.g. distribution of boron in a thicker region that suggests a diffusion of this dopant in the coating of the sample) found using a rough sample substrate was related to a higher power conversion efficiency.
除了生产成本低以及使用无毒且丰富的原材料外，硅基薄膜太阳能电池还具有可构建为多结器件（如串联或三结太阳能电池）的优势。由氢化非晶硅（a-Si:H）顶电池和微晶硅（μc）Si:H底电池组成的串联电池制成的硅薄膜模块已在市场上有售。在这项工作中，研究了最先进的射频（rf）脉冲辉光放电（PGD）飞行时间质谱（TOFMS）商业仪器对具有1μm厚ZnO:Al的2mm厚玻璃基板上的串联结太阳能电池进行深度剖析分析的分析潜力。使用毫秒和亚毫秒rf-PGD模式以及所用商业仪器中可用的所谓“低质量模式”，比较了两种薄膜串联光伏器件的深度剖面表征。比较了两种样品制备程序，即使用平整或粗糙的电池基板，并研究了两种情况下掺杂元素（磷、硼和锗）的分布。通过rf-PGD-TOFMS获得的实验结果以及样品的电学测量表明，使用粗糙样品基板时，在硅层中发现的掺杂元素深度分辨率较差（例如，硼在较厚区域的分布表明该掺杂剂在样品涂层中扩散）与较高的功率转换效率有关。
