晶硅太阳电池黑斑分析

Analysis on Black Spot in Boron—Doped p-Type Crystalline Silicon Solar Cells

p型单晶硅太阳电池在EL检测过程中,部分电池片出现黑斑现象。结合X射线能谱分析(EDS),对黑斑片与正常片进行对比分析,发现黑斑片电池与正常电池片大部分表面的成分相同,排除了镀膜及丝网印刷过程中产生黑斑的可能。利用X射线荧光光谱分析(XRF)测试了同一电池片的黑斑区域与正常区域,发现黑斑处Ca含量较大,并出现Sr、Ge和S等杂质元素。将6个档位的电池片制备成2cm×2cm的电池样片,利用光生诱导电流测量了每个电池的外量子效率(EQE)。在460~1 000nm波长范围内,同一电池片黑斑处与正常处的EQE相差较大,说明黑斑的出现与原生硅片缺陷无关,应归结于电池片生产过程中引入的杂质缺陷。给出了杂质引入的原因以及解决途径,从而显著减小了黑斑片产生的几率。

In the process of EL testing of p-type crystalline silicon solar cells,black spot occurs in part of cells.Combining with X-ray energy spectrum analysis（EDS）,contrastive analysis on the black spot cells and normal cells indicates that most of the surface component of the black spot cells and the normal cells is the same,which excludes the possibilities of appearing black spots in the process of coating and screen printing.Tests performed on the shading area and the normal area from the same cell by X-ray fluorescence spectrometry（XRF）show that Ca content is larger in the shading area,even other impurity elements as Sr,Ge or S appearing in the same shading area.External quantum efficiency（EQE）of each cell was teated by measuring the light-induced current,and it showed that there is a big difference between the shading and the normal areas within the wavelength range of 460-1 000 nm,which indicates that not the primary silicon defects but the impurity defects introduced in the production process of solar cells leads to the black spot.The causes of impurities and solutions were given,significantly reducing the production probability of black spot cells.