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.

碱性元素在多晶Cu（In，Ga）SE2（CIGS）薄膜太阳能电池中起重要作用。钠（NA）对CIGS太阳能电池性能的积极作用是通过使用苏打石灰玻璃而不是无钠的底物的意外作用。后来的钾（K）似乎是细胞效率的进一步提高。 Currentliy，较重的碱性rubidium（RB）和剖宫产（CS）已被确定为提高性能的进一步候选者。已经进行了许多实验，以找出NA是否主要在晶界或大部分晶粒或两者兼而有之。原子探针断层扫描（APT）的测量表明，Na在晶粒内以及晶界内，在晶粒边界内强烈分离。但是到目前为止，尚不清楚晶界的钝化是否是Na的主导作用，或者是Na在晶粒中掺杂的增加是主要效应。 Na和其他碱元素对CIGS缺陷物理的影响也未知，因为在大多数以前的实验中，在NA存在下生长的CIGS层与没有NA的层进行了比较。因此，NA对CIGS层生长过程中缺陷形成的影响无法与其对光电特性的影响分开。通过在CIGS生长完成后用碱元素的CIGS层的沉积处理，可以清楚地识别出碱对CIGS层和太阳能电池的缺陷物理和光电特性的影响。该项目的目的是更好地了解钠和其他碱金属对CIGS层和太阳能电池性质的积极作用，并研究不同碱元素之间的相互作用。这包括区分晶界，晶粒散装和界面效应的任务。对碱性元素在CIGS中的影响的基本了解可以帮助进一步提高细胞效率。