AlkaCIGS - Effects of Alkali elements in Cu(In,Ga)Se2 thin films and solar cells

AlkaCIGS - 碱金属元素对 Cu(In,Ga)Se2 薄膜和太阳能电池的影响

• 批准号: 381204229
• 负责人: Dr. Roland Würz
• 金额: --
• 依托单位: Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/381204229?language=en
• 关键词: AlkaCIGS; Effects; Alkali; elements; Cu

Alkali elements play an important role in polycrystalline Cu(In,Ga)Se2 (CIGS) thin-film solar cells. The positive effect of sodium (Na) on CIGS solar cell performance was found by accident by using soda lime glass instead of sodium free substrates. Later potassium (K) appeared as a further booster for cell efficiency. Currentliy, the heavier alkali elements rubidium (Rb) and cesium (Cs) have been identified as further candidates to increase the performance. Many experiments have been done to find out if Na mainly acts at the grain boundaries or in the bulk of the grains or both. Atomic Probe Tomography (APT) measurements revealed that Na is inside the grains as well as in the grain boundaries, where it strongly segregates. But so far it is unclear whether passivation of grain boundaries is the dominating effect of Na or if the increase of p doping in the grain bulk by Na is the main effect. The effect of Na and other alkali elements on the defect physics of CIGS is also unknown, since in most former experiments CIGS layers grown in the presence of Na were compared to layers grown without Na. Therefore, the effect of Na on the formation of defects during the CIGS layer growth could not be separated from its effect on opto-electronic properties. By post deposition treatment of CIGS layers with alkali elements after CIGS growth is finished, as to be realized in this project, the effect of alkalis on defect physics and opto-electronic properties of CIGS layers and solar cells can be clearly identified. The aim of the project is to better understand the positive effect of sodium and other alkali metals on the CIGS layer and solar cell properties and to investigate the interaction between the different alkali elements. This includes a task to distinguish between grain boundary, grain bulk and interface effects. The better fundamental understanding of the effects of alkali elements in CIGS could help to further improve cell efficiency.

碱元素在多晶Cu(in,Ga)Se2 （CIGS）薄膜太阳能电池中起着重要的作用。钠（Na）对CIGS太阳能电池性能的积极影响是偶然发现的，用钠石灰玻璃代替无钠衬底。后来钾(K)作为细胞效率的进一步助推器出现。目前，较重的碱元素铷（Rb）和铯（Cs）已被确定为进一步提高性能的候选元素。为了弄清钠离子是主要作用于晶界，还是主要作用于晶界，或者两者兼而有之，已经做了许多实验。原子探针断层扫描（APT）测量显示，Na在晶粒内部和晶界中，在那里它强烈偏析。但目前还不清楚晶界钝化是Na的主要作用还是Na增加了晶体中p的掺杂是主要作用。Na和其他碱元素对CIGS缺陷物理的影响也是未知的，因为在大多数先前的实验中，在Na存在下生长的CIGS层与没有Na生长的CIGS层进行了比较。因此，在CIGS层生长过程中，Na对缺陷形成的影响与其对光电性能的影响是不可分割的。通过在CIGS生长完成后对CIGS层进行碱元素的后沉积处理，本项目将实现碱元素对CIGS层和太阳能电池缺陷物理和光电性能的影响。该项目的目的是为了更好地了解钠和其他碱金属对CIGS层和太阳能电池性能的积极影响，并研究不同碱金属之间的相互作用。这包括一项区分晶界、晶粒体积和界面效应的任务。更好地了解碱元素在CIGS中的作用有助于进一步提高电池效率。