铜铟镓硒（CIGS）四元陶瓷靶材烧结制备及性能研究

发布时间：2018-04-02 11:07

本文选题：铜铟镓硒靶材　切入点：热压烧结　出处：《清华大学》2015年博士论文

【摘要】：Cu(In_1-xGax)Se_2薄膜太阳电池因其优良的性能已成为最具产业化前景的电池之一。采用溅射CIGS四元陶瓷靶材后退火的工艺,可获得大面积均匀且性能稳定的CIGS吸收层和电池。该工艺是一种适合产业化的电池生产工艺方法。该工艺的关键是高质量CIGS靶材的获得。为获得高质量CIGS靶材,本文系统研究烧结工艺条件对靶材性能的影响,并深入分析分层等烧结缺陷的产生机理。在高质量CIGS靶材制备基础上,提出并研究了原位掺Na CIGS靶材的制备工艺;创新性提出一种溅射富Se CIGS靶材加无Se源热处理二步法制备CIGS吸收层和CIGS电池的工艺思想,并研究了富Se CIGS靶材的制备工艺。本文主要研究内容和成果如下:采用热压烧结Cu_2Se、In_2Se_3和Ga2Se3混合粉末的工艺制备CIGS靶材,深入系统地研究了粉末球磨时间、烧结温度、烧结压力和烧结时间等工艺参数对CIGS靶材密实率、成分、相组成和断面形貌等性能参数的影响。通过优化实验工艺,获得最高密实率达96.4%无缺陷的CIGS靶材。针对烧结过程中产生分层、开裂和表面剥落等烧结缺陷的问题,深入分析了烧结缺陷产生的内在机制,并提出烧结缺陷产生的机理模型:烧结过程中产生的低熔点相在烧结压力的作用下沿CIGS晶界发生流动性扩散,当液相通过流动扩散且相互贯连时靶材发生沿晶界的破坏。采用热压烧结Cu_2Se、In_2Se_3、Ga2Se3和NaF混合粉末的工艺实现原位掺Na CIGS靶材的制备。研究发现,Na元素具有提高CIGS靶材结晶性的作用,在NaF添加量为0.1?0.5 mol%的成分范围内获得高密实率的掺Na CIGS靶材,该成分范围覆盖了CIGS吸收层最优Na添加量。制备得到的掺Na CIGS靶材最高密实率达96.4%。分析了过量的Na致CIGS靶材分层的作用机理:Na以Na2Sex形式在CIGS晶界上富集并导致CIGS晶界的弱化,进而使烧结过程中的液相更容易发生流动扩散而诱发靶材分层。通过热压烧结CIGS粉末和Se粉末实现了富Se CIGS靶材的制备。发现Se的加入起到辅助烧结的作用,制备得到的富Se CIGS靶材最高密实率达到98.3%。通过溅射富Se CIGS靶材后在高纯N2气氛中退火的方法实现了无Se气氛条件下制备具有富Se成分和理想电学性能的CIGS吸收层,并制备得到CIGS电池。本文初步研制得到的CIGS电池的最高光电转化效率达8.95%。
[Abstract]:Cu(In_1-xGax)Se_2 thin film solar cells have become one of the most promising batteries due to their excellent properties. A large area uniform and stable CIGS absorbent layer and battery can be obtained. This process is a suitable process for the production of batteries. The key to this process is to obtain high-quality CIGS targets. In this paper, the effects of sintering process conditions on the properties of targets are systematically studied, and the mechanism of sintering defects such as delamination is analyzed. Based on the preparation of high quality CIGS targets, the preparation process of in situ doped Na CIGS targets is proposed and studied. A novel two-step method for fabricating CIGS absorbing layer and CIGS battery by sputtering se rich CIGS target and non se source heat treatment was proposed. The main contents and results of this paper are as follows: the preparation of CIGS targets by hot-pressing sintering of Cu2SeInSe _ 3 and Ga2Se3 mixed powders was studied systematically, and the milling time and sintering temperature of the powders were studied systematically. The effects of sintering pressure and sintering time on the properties of CIGS target, such as compactness, composition, phase composition and section morphology, were studied. The CIGS target with the highest compaction rate of 96.4% was obtained. In view of the problems of sintering defects such as delamination, cracking and surface exfoliation during sintering, the inherent mechanism of sintering defects was deeply analyzed. The mechanism model of sintering defects is put forward: the fluidity diffusion of low melting point phase in sintering process along CIGS grain boundary under the action of sintering pressure. When the liquid phase diffuses through the flow and intersects with each other, the target material is destroyed along the grain boundary. The in situ doped Na CIGS target is prepared by hot pressing sintering Cu2Se2SeIn2Se3Ga2Se3 and NaF mixed powder. It is found that the Na element can improve the crystallinity of the CIGS target. The amount added in NaF is 0. 1? In the range of 0.5 mol%, Na CIGS doped target with high compactness was obtained. The optimum amount of Na in the CIGS absorbent layer is covered by this composition range. The highest density ratio of Na doped CIGS target is 96.40.The mechanism of CIGS target delamination induced by excessive Na is analyzed, which is enriched on the CIGS grain boundary in the form of Na2Sex, which leads to the weakening of CIGS grain boundary. Thus, the liquid phase in the sintering process is more prone to flow diffusion and induce target delamination. The preparation of se rich CIGS target is realized by hot pressing sintering CIGS powder and se powder. It is found that the addition of se plays an auxiliary role in sintering. The highest compactness of the prepared se rich CIGS target is up to 98.3. By sputtering the se rich CIGS target and annealing in high purity N 2 atmosphere, the CIGS absorbing layer with rich se composition and ideal electrical properties can be prepared under the condition of no se atmosphere. The CIGS battery was prepared and the maximum photoelectric conversion efficiency of the CIGS battery was 8.95%.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TQ174.1

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