用电致发光(EL)技术检测P型常规单晶硅太阳电池,发现角部发黑问题.研究其与电池制造工艺或单晶硅材料的相关性,测试正常和黑角电池片的电性能参数发现黑角电池光电转换效率低于19.90％.经腐蚀剥离电池分析基底单晶硅材料,发现黑角处材料的少子寿命比中心位置处低约50μs以上.用Schimmel A择优腐蚀液剥离黑角电池,在黑角位置的硅材料明显出现位错缺陷,且缺陷数量高于中心区域.经多项实验检测分析,初步得出EL测试出现黑角边问题的单晶硅电池与基底硅材料的原生缺陷有关.

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2 cm×2 cm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460～1 000 nm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.

SiN x /SiO x passivation and double side P-diffusion gettering treatment have been used for the fabrication of c-Si solar cells. The solar cells fabricated have high open circuit voltage and short circuit current after the double P-diffusion treatment. In addition to better surface passivation effect, SiN x /SiO x layer has lower reflectivity in long wavelength range than conventional SiN x film. As a consequence, such solar cells exhibit higher conversion efficiency and better internal quantum efficiency, compared with conventional c-Si solar cells.

作为制备昌体硅太阳电池的核心技术,扩散后方块电阻的均匀性显得非常重要.通过对现有晶体硅太阳电池扩散工艺进行改进,提出一种间断性变温磷扩散工艺.此工艺应用于物理冶金多晶硅太阳电池制备中,所形成的p-n结表面杂质浓度低,杂质分布均匀,提高了硅片少子寿命和方块电阻的均匀性,有利于电子的收集,减少了太阳电池因复合造成的效率损失,从而提高电池片最终光电转换效率.与现有工艺相比,减少了三氯氧磷、干氧的使用量,缩短了工艺时间,节约了生产成本.

PC1D simulation software was used to simulate SiO2/SiNx/SiNx stack-layer passivation antireflection structure of p-type metallurgical grade silicon solar cells. The simulation results show that it can significantly improve external quantum efficiency and surface antireflection of the cell when a SiO2 passivation layer is introduced in the SiNx/SiNx double-layer antireflection structure, and ultimately improve the cell conversion efficiency. With the increasing of SiO2 film thickness, the surface reflectance of the cell increases at first and then decreases, while the external quantum efficiency and conversion efficiency of the cell show an opposite trend. There is little change on the efficiency of the cell when the thickness of SiO2 passivation film ranges from 2 nm to 8 nm, while the cell’s efficiency significantly decreases when the thickness of silicon dioxide layer is greater than 8 nm. Maximum efficiency (18.04%) appears when the thickness of silicon dioxide layer in the SiO2/SiNx/SiNx stack-layer passivation antireflection structure is 6 nm.

In recent years, N-type crystalline silicon solar cells have attracted much attention in the field of high efficiency and low cost solar cell due to its great advantages, such as long minority carrier lifetime, low light-in?duced degradation and good low-light response. PC1D simulation is used to analyze the back emitter N-type crystal?line silicon solar cells. The results show that back emitter doping concentration, junction depth, back surface recom?bination velocity, front surface field doping concentration and front surface recombination velocity have a greater im?pact on the cell conversion efficiency, and especially the front and back surface recombination velocity are the most. But the front surface field doping depth has less affect on the performance of the cell. For the front surface recombi?nation, when the surface recombination velocity is less than 1×103 cm/s, there is a small affect on the performance of the cell, but when the surface recombination velocity is greater than 1×103 cm/s, the conversion efficiency of the cell decreases rapidly. The effects of back surface recombination on cell efficiency is even more obvious when the back surface recombination velocity is greater than 1 × 104 cm/s, the conversion efficiency of the cell arises a sharp de?cline. As the back surface recombination velocity increases to 1 × 106 cm/s, the efficiency of the cell drops to less than 5%. In a low back surface recombination velocity range (10~103 cm/s), the cell can obtain high conversion effi?ciency.

The high pure Cu, In, S powder was mixed by the ratio of 1:0.1:1.2, followed by vacuum evaporated on the glass slide. The optimum heat-treatment condition for the conductive type conversion of the thin films was studied. The effects of different heat-treatment process on the properties of thin films, including the structure, surface morphology inner chemical composition and optical properties, were also studied. Experimental results show that optimized heat treatment condition is critical for the conductive type conversion of CuInS2 thin films. The CuInS2 thin film prepared with heat-treatment for 30mins at 360℃ presents N-type chalcopyrite structure, and the thin film is flat slightly with graininess and compactness. The intrinsic absorption edge is 1.46eV, and the direct optical band gap is 1.38eV. The CuInS2 thin film prepared with heat-treatment for 20 mins at 370℃ is also N-type chalcopyrite structure, but contains a small amount of CuS2 component, the compactness is better, yet the roughness is increased. The intrinsic absorption edge of the thin film is 1.42eV, showing red shift, and the direct optical band gap is 1.40eV. The CuInS2 thin film prepared with heat-treatment for 30 mins at 370 ℃ is P-type chalcopyrite structure, with the direct optical band gap of 1. 37 eV. The photoabsorption coefficients of the three kinds of thin films are all over 104 order of magnitudes. The In and Cu contents in the CuInS2 thin films play a decisive role in the conductive thpe conversion, while the S and In contents directly depend on the heat treatment conditions.