空间高效硅太阳电池减反射膜设计与数值分析

结合AM0太阳光谱特性对空间硅太阳电池的减反射膜进行了设计分析,得到了最小反射时的最佳膜厚.分别讨论了单、双、三层减反射膜厚度变化对反射率的影响,并对有钝化层的SiO2(94nm)/TiO2(60nm)双层减反射膜进行了优化设计,优化后硅太阳电池的短路电流和效率分别提高了2.1%和1.4%.     

色散效应对钝化硅太阳电池减反射膜系设计的影响

在考虑折射率色散效应基础上,以加权平均反射率作为评价函数,通过智能优化算法对空间硅太阳电池减反射膜进行优化设计,得到了最佳的膜厚参数,并与不考虑色散下设计的减反射膜进行了比较。对MgF2/TiO2,SiO2/TiO2双层减反射膜,与不考虑色散情形相比,考虑色散下优化后的最小加权平均反射率分别减小了36.6%和37.6%;对具有厚度为15 nm的SiO2钝化层的硅太阳电池的MgF2/TiO2,SiO2/TiO2减反射膜重新优化设计,与不考虑色散情形相比,考虑色散下优化后的最小加权平均反射率分别减小了43.9%和33.7%;对具有不同厚度钝化层的空间硅太阳电池,在考虑色散下进行了减反射膜的优化设计。结果发现,随着钝化层厚度的增加,所得减反射膜的最小加权平均反射率也随之增大,减反射效果越来越弱。最后,在考虑与未考虑色散情形下,将钝化层膜厚也作为反演参量后重新设计。结果表明:在色散情形下所设计的减反射膜更佳,对于MgF2/TiO2/SiO2（钝化层）膜系,最佳膜厚参量为d1（MgF2）=97.6 nm,d2（TiO2）=40.2 nm,d3（SiO2）=4.9 nm;对于SiO2/TiO2/SiO2（钝化层）,最佳膜厚参量为d1（SiO2）=85.1 nm,d2（TiO2）=43.4 nm,d3（SiO2）=1.8 nm。     

高效硅太阳能电池减反射膜系折射率分布

基于多层减反射膜的等效分析原理,结合遗传算法的全局寻优的特性,对硅太阳电池的减反射膜进行了遗传算法优化设计,并对双层减反射膜各层膜折射率的分布对膜系减反射效果的影响进行了进一步的数值分析,得到最优的膜系折射率分布规律,并推广到多层减反射膜.分别设计优化了常规材料和新型纳米材料三层减反射膜,并进行进一步论证,最终发现,高...     

多孔硅层湿法腐蚀现象的研究

阳极氧化法制备的多孔硅层分别经 1% HF、 1% NH3 / H2 O2 和 0 .0 5 % Na OH三种溶液在室温下进行湿法腐蚀 ,并用傅里叶变换红外光谱 (FTIR)和扫描电子显微镜 (SEM)对其变化进行了研究。腐蚀后多孔硅的表面形貌出现明显的刻蚀现象。红外吸收光谱表明 ,在用 1% NH3 / H2 O2 溶液腐蚀时 ,多孔硅层中 Si- O键和 Si- H键的强度增加 ,H- O键的强度下降 ;用 1% HF溶液和 0 .0 5 % Na OH溶液的腐蚀结果正好相反。 0 .0 5 %Na OH溶液对多孔硅层的腐蚀现象类似于强碱性溶液对单晶硅腐蚀表现出的各向异性 ,对多孔硅层厚度的腐蚀速度比 1% HF溶液的高     

高效率MINP硅太阳电池的研制

用扩散法制作MINP硅太阳电池的轻掺杂N区,用PECVD方法淀积的Si_3N_4作其减反射膜,在电阻率为1.5±0.5Ω·cm的P型硅衬底上制取了转换效率为16.5%的MINP太阳电池(有效面积AM1.5、100mw/cm~2、25℃)。本文分析Si_3N_4作MINP电池减反射膜的优点,并对限制MINP太阳电池性能进一步提高的因素进行讨论。     

非晶硅太阳电池减反射膜的设计

基于非晶硅太阳电池的工作原理,对其减反射膜进行研究．根据四分之一波长作用原理得到反射率最小时的厚度优化参数．单层减反射膜选用ITO（m=2．0,d=75nm）,加权平均反射率为5．91％．双层膜选用MgF2／ITO,厚度分别为111nm和75nm,加权平均反射率为3．72％．此外,还作出反射率随波长的变化曲线,并通过计算仿真结果进行比较说明如何选材：对于单层减反射膜,采用折射率小的材料能取得更好的效果,而对于双层减反射膜,采用折射率上低下高形式,能取得更好的效果．     

色散效应对GaAs太阳电池双层减反射膜的影响

考虑双层减反射膜材料的折射率色散效应,采用光学干涉矩阵法计算了SiO2/ZnSe和SiO2/ZnS两种GaAs太阳电池双层减反射膜的反射率与波长的函数曲线,以及加权平均反射率随着顶层减反射膜SiO2厚度变化的函数曲线,并与未考虑色散效应的情况进行了对比.计算结果表明,色散效应对双层减反射膜的反射率有较大的影响,特别是对300～500nm波长范围的影响更大,且对不同材料的减反射膜的影响也是不同的.与未考虑色散效应的情况相比,考虑色散效应后,SiO2/ZnSe双层减反射膜的最小加权平均反射率从1.14%增加到1.55%,而SiO2/ZnS双层减反射膜的最小加权平均反射率却从1.49%减小到1.46%.     

单晶硅太阳电池纳米减反射膜的研究

报道了用热喷涂工艺制备单晶硅太阳电池纳米减反射膜的研究结果 ,讨论了衬底温度对 Ti Ox 纳米减反射膜结构及折射率的影响 ,优化了热喷涂的工艺条件 ,并研究了 Ti Ox 纳米减反射膜对单体太阳电池效率的贡献。实验证明 ,用热喷涂工艺制备的纳米 Ti Ox 减反射膜可使 1 0 0 mm× 1 0 0 mm单体太阳电池的平均光电转换效率增加 8%～ 9%。     

色散效应对GaAs太阳电池双层减反射膜的影响

考虑双层减反射膜材料的折射率色散效应,采用光学干涉矩阵法计算了SiO2/ZnSe和SiO2/ZnS两种GaAs太阳电池双层减反射膜的反射率与波长的函数曲线,以及加权平均反射率随着顶层减反射膜SiO2厚度变化的函数曲线,并与未考虑色散效应的情况进行了对比.计算结果表明,色散效应对双层减反射膜的反射率有较大的影响,特别是对300～500nm波长范围的影响更大,且对不同材料的减反射膜的影响也是不同的.与未考虑色散效应的情况相比,考虑色散效应后,SiO2/ZnSe双层减反射膜的最小加权平均反射率从1.14%增加到1.55%,而SiO2/ZnS双层减反射膜的最小加权平均反射率却从1.49%减小到1.46%.     

Pt纳米粒子辅助化学刻蚀制备硅减反射层

制备高效硅太阳能电池,需要在整个太阳光谱范围内进行有效陷光和保持低反射率.基于贵金属粒子湿法辅助刻蚀方法,在P型(100)单晶硅表面溅射了一层厚度为1～5 nm的非连续分布Pt粒子层作为催化剂,浸入HF/H2O2的水溶液中进行湿法刻蚀,制备的减反射层在300～800 nm入射光波段范围的平均减反射率低于7%,减反射效果明显优于传统的热碱溶液刻蚀单晶硅所得的织构.通过进一步优化工艺参数,并增镀SiNx等减反射膜,陷光效果将会进一步提高.研究结果为高效太阳能电池的设计提供了新思路.     

Double layer antireflection coating for high-efficiency passivatedemitter silicon solar cells

Recent high-efficiency silicon solar cells employ high-quality oxides both for surface passivation and as a rudimentary antireflection coating. This gives over 3% reflection at the cell front surface, even though the surface is microstructured. A double layer antireflection coating applied to cells with reduced SiO₂ thickness reduces the cell reflection. However, although reflection is minimized by reducing the oxide thickness to values below 100 Å, a rapid falloff in both open-circuit voltage and short-circuit current is observed experimentally once this thickness is reduced below 200 Å. The best compromise is found when oxide thickness is 250 Å which allows improved short-circuit current density without appreciable loss in open-circuit voltage     

Influence of window layer thickness on double layer antireflection coating for triple junction solar cells

The optimization of a SiO₂/TiO₂,SiO₂/ZnS double layer antireflection coating（ARC）on Ga_0.5In_0.5P/In_0.02Ga_0.98As/Ge solar cells for terrestrial application is discussed.The Al_0.5In_0.5P window layer thickness is also taken into consideration.It is shown that the optimal parameters of double layer ARC vary with the thickness of the window layer.     

具有亚表面损伤层基底表面的激光减反膜设计

光学材料的亚表面损伤层（SSD）是激光光学领域内的研究热点之一。亚表面损伤层的存在将导致其表面薄膜特性发生变化,尤其是在高精度低损耗激光薄膜的设计与制造中亚表面损伤层必须给予考虑。文中研究了亚表面损伤层的物理特性,并借助于椭圆偏振仪测量基底表面的椭偏光谱,反演计算出SSD 的物理厚度和折射率梯度。通过计算得到了亚表面的深度和梯度对激光减反膜反射率光谱的影响,证明了亚表面深度对反射率的影响具有周期效应。在考虑亚表面损伤层的深度和梯度存在的基础上,对激光减反膜的设计进行了理论修正,数值实验结果证明通过膜系的修正可以实现633 nm 处的零反射。     

Effect of antireflection coatings and coverglasses on silicon solar cell performance

The high reflectivity of the polished silicon surface of the newer N⁺/P silicon solar cells has emphasized the need for properly designed antireflection coatings to obtain improved solar cell performance. The problem is complicated by the facts that solar cells are generally tested in air, but are for their final application covered with a glass or quartz slide which is adhesive-bonded to the cell surface, and further, that solar cells operating in a nuclear particle radiation environment change their spectral response and are frequently optimized for performance at the end of design-life. Experiments have been performed to explore the antireflection characteristics of thin films of silicon monoxide which have been evaporated on the solar cell surface. The effect of the antireflection coating thickness on cell response as a function of wavelength has been determined and the improvement in cell short circuit current for Air Mass Zero space sunlight evaluated. Included in this study was the evaluation of the antireflection characteristics after the application of a coverglass with adhesive over the antireflection coating. For comparison, coverglasses were also applied to bare cells with no antireflection coating present. In all cases the various coating comparisons were based on the cell short-circuit current performance in Air Mass Zero sunlight.     

基于反射光谱的单层抗反射膜的非在位膜厚精确控制

提出一种基于反射光谱分析的非在位膜厚控制技术,首先利用椭圆偏振光谱仪确定波长300～1 700 nm范围内的薄膜折射率,由此确定对应于特定波长(如1 550 nm)的最佳抗反射(AR)镀膜沉积条件。然后计算最佳AR镀膜厚度所对应的反射谱,得到相应的CIE标准色谱坐标。通过对比实测镀膜颜色和计算得到的最佳颜色,可以实现小尺寸器件端面上AR镀膜厚度的优化控制。利用这一方法,由等离子体增强化学气相沉积(PECVD)制备的SiNx单层AR镀膜,获得了4.4×10-4的反射率。     

窗口层对三结电池双层减反膜的影响

窗口层的厚度对高效三层太阳能电池具有重要影响。本文针对太阳能电池的地面应用,优化了三节电池（Ga0.5In0.5P/In0.02Ga0.98As/Ge）的双层反射膜（SiO2/TiO2, SiO2/ZnS）。同时讨论了在双层减反膜优化结构下,变化Al0.5In0.5P窗口层厚度引起反射率的变化。     

Performance enhancement of multicrystalline silicon solar cells and modules using double‐layered SiNx:H antireflection coatings

Silicon nitride coating deposited by the plasma‐enhanced chemical vapor deposition method is the most widely used antireflection coating for crystalline silicon solar cells. In this work, we employed double‐layered silicon nitride coating consisting of a top layer with a lower refractive index and a bottom layer (contacting the silicon wafer) with a higher refractive index for multicrystalline silicon solar cells. An optimization procedure was presented for maximizing the photovoltaic performance of the encapsulated solar cells or modules. The dependence of their photovoltaic properties on the thickness of silicon nitride coatings was carefully analyzed. Desirable thicknesses of the individual silicon nitride layers for the double‐layered coatings were calculated. In order to get statistical conclusions, we fabricated a large number of multicrystalline silicon solar cells using the standard production line for both the double‐layered and single‐layered antireflection coating types. On the cell level, the double‐layered silicon nitride antireflection coating resulted in an increase of 0.21%, absolute for the average conversion efficiency, and 1.8 mV and 0.11 mA/cm² for the average open‐circuit voltage and short‐circuit current density, respectively. On the module level, the cell to module power transfer factor was analyzed, and it was demonstrated that the double‐layered silicon nitride antireflection coating provided a consistent enhancement in the photovoltaic performance for multicrystalline silicon solar cell modules than the single‐layered silicon nitride coating. Copyright © 2015 John Wiley & Sons, Ltd.     

Reflection distributions of textured monocrystalline silicon: implications for silicon solar cells

A common misconception is that alkaline textured silicon solar cell surfaces are characterised by features that are pyramidal and bounded by {111} planes. In preference to the typical approach of observing scanning electron microscope images, we analyse reflection distributions from various pyramidal textures and find that {111} faceted pyramids are a poor approximation to the features on such surfaces. We conclude that features are hillocks, with an octagonal base. Furthermore, the characteristic base angle of the texture depends on the etchant and is closer to 50–52° than the commonly accepted value of 54.74°. Analyses of antireflection, light trapping, photogeneration and surface recombination properties of textured surfaces should take this feature morphology into account. The base angle has a strong influence on the hemispherical reflectance of the textured surface, with higher angles resulting in reduced reflectance. The influence of this reflection enhancement upon device performance is smallest when an optimised antireflection coating is applied; compared with an array of {111} faceted pyramids, a hillock morphology with 50° base angle results in a 0.2% reduction in photogenerated current in a typical cell. Additionally, as base angle is reduced, an encapsulant of increasingly higher refractive index is required to drive internal reflection at the air–glass interface of light initially reflected from the cell surface. The development of texturing processes resulting in higher base angles is encouraged. Copyright © 2012 John Wiley & Sons, Ltd.     

Influence of double- and triple-layer antireflection coatings on the formation of photocurrents in multijunction III–V solar cells

The results of simulation by the transfer-matrix method of TiO₂/SiO₂ double-layer and TiO₂/Si₃N₄/SiO₂ triple-layer antireflection coatings for multijunction InGaP/GaAs/Ge heterostructure solar cells are presented. The TiO₂/SiO₂ double-layer antireflection coating is experimentally developed and optimized. The experimental spectral dependences of the external quantum yield of the InGaP/GaAs/Ge heterostructure solar cell and optical characteristics of antireflection coatings, obtained in the simulation, are used to determine the photogenerated current densities of each subcell in the InGaP/GaAs/Ge solar cell under AM1.5D irradiation conditions (1000 W/m²) and for the case of zero reflection loss. It is shown in the simulation that the optimized TiO₂/Si₃N₄/SiO₂ triple-layer antireflection coating provides a 2.3 mA/cm² gain in the photocurrent density for the Ge subcell under AM1.5D conditions in comparison with the TiO₂/SiO₂ double-layer antireflection coating under consideration. This thereby provides an increase in the fill factor of the current–voltage curve and in the output electric power of the multijunction solar cell.     

界面粗糙度对真空紫外光学薄膜光谱性能影响研究

设计了193 nm窄角度和宽角度入射增透膜以及正入射高反膜,其中增透膜s和p偏振光透射率的最大偏差分别为0.17%和0.44%。结合标量散射理论和等效吸收层近似理论,多层膜间的粗糙界面等效为薄的吸收层,基于薄膜本征传输矩阵计算分析了不同界面粗糙度下的光谱性能。研究发现,薄膜光谱性能随着界面均方根粗糙度的增加而急剧退化,高反膜反射带宽也随之降低,达到4 nm时,宽角度入射增透膜和高反膜光谱性能在193 nm处分别退化2.04%和2.09%。界面粗糙度是影响高光谱性能真空紫外光学薄膜制备的重要因素。