掺Na制备柔性聚酰亚胺衬底CIGS薄膜太阳电池

研究了Na掺入对低温沉积柔性聚酰亚胺(PI)衬底Cu(In,Ga)Se2(CIGS)薄膜的结构和电学特性影响。研究结果表明:Na元素的掺入使Ga元素的扩散受到了阻滞,但对CIGS薄膜晶粒尺寸没有明显的影响,少量的Na可提高CIGS薄膜的载流子浓度和降低电阻率;Na的掺入可明显提高CIGS薄膜太阳电池的器件特性,通过优化掺Na工艺,制备的柔性PI衬底—CIGS薄膜太阳电池的最高转换效率达到10.4%。     

金属Cr阻挡层对柔性不锈钢衬底Cu(In,Ga)Se2太阳电池性能的影响

研究了Cr扩散阻挡层对柔性不锈钢衬底Cu(InxGa1-x)Se2(CIGS)太阳电池性能的影响.XRD和SEM分析表明,Cr阻挡层能够部分阻挡Fe等杂质从不锈钢衬底热扩散进入CIGS吸收层中,同时可以显著降低CIGS吸收层的粗糙度,提高薄膜结晶质量.从衬底扩散进入吸收层中的Fe元素以FeInSe2的形式存在,并形成FeCu等深能级缺陷,钝化了器件的性能.相同工艺条件下,在玻璃、不锈钢以及不锈钢/Cr阻挡层上所制备电池的(有效面积0.87cm2)转换效率分别为10.7%,7.95%和8.58%,不锈钢衬底电池效率的提高归因于Cr阻挡层的作用.     

联氨对化学水浴沉积ZnS薄膜的影响

在A(ZnSO4、SC(NH2)2、NH4OH)和含有联氨的B(ZnSO4、SC(NH2)2、NH4OH、(NH2)2)两种水溶液中采用化学水浴法沉积ZnS薄膜,研究了联氨对薄膜沉积过程和薄膜性质的影响.结果表明,加入少量联氨以后,薄膜沉积速度明显增加.两种溶液沉积的ZnS都为立方相结构,且含有联氨的B溶液沉积的ZnS薄膜表面附着颗粒较少.在含有联氨的B溶液中沉积的ZnS薄膜结晶度和短波区的透过率均高于A溶液沉积的ZnS薄膜.将两种溶液沉积的ZnS薄膜作为电池缓冲层制备铜铟镓硒(CIGS)薄膜太阳电池,加入联氨沉积的ZnS制备的CIGS电池转换效率达到7.77%,比不加联氨沉积的ZnS制备的CIGS电池转换效率提高了1.3%.     

金属Cr阻挡层对柔性不锈钢衬底Cu(In,Ga)Se2太阳电池性能的影响

研究了Cr扩散阻挡层对柔性不锈钢衬底Cu(InxGa1-x)Se2(CIGS)太阳电池性能的影响.XRD和SEM分析表明,Cr阻挡层能够部分阻挡Fe等杂质从不锈钢衬底热扩散进入CIGS吸收层中,同时可以显著降低CIGS吸收层的粗糙度,提高薄膜结晶质量.从衬底扩散进入吸收层中的Fe元素以FeInSe2的形式存在,并形成FeCu等深能级缺陷,钝化了器件的性能.相同工艺条件下,在玻璃、不锈钢以及不锈钢/Cr阻挡层上所制备电池的(有效面积0.87cm2)转换效率分别为10.7%,7.95%和8.58%,不锈钢衬底电池效率的提高归因于Cr阻挡层的作用.     

CIGS薄膜太阳能电池结构分析

阐述了影响铜铟镓硒(CIGS)薄膜太阳能电池性能和效率的技术因素,包括CIGS半导体材料的晶体结构、电池的结构组成、衬底材料的选择以及CIGS薄膜的Na掺杂等。分析了多元共蒸发法、硒化法沉积CIGS吸收层以及化学水浴法沉积Cd S缓冲层的具体工艺和特征,介绍了柔性CIGS薄膜太阳能电池的卷对卷技术,最后就CIGS薄膜太阳能电池的研发与商业化生产中遇到的挑战及解决方法进行了分析与归纳。     

PI衬底柔性透明硅薄膜太阳能电池的制备及性能

利用硬质玻璃为载板,采用传统硅薄膜太阳能电池生产设备,在聚酰亚胺(PI)塑料薄膜衬底上沉积了B掺杂的ZnO(BZO)薄膜,并以此作为前电极制备了单节电池结构及多节串联一体结构的非晶硅(a-Si)太阳能电池;研究了PI衬底上BZO薄膜的光学及电学性能。结果表明,PI衬底上沉积BZO薄膜后在300~1 200 nm波长范围的透光率为76.63%,方块电阻19.7?/□。所制备的单节和多节串联一体结构的a-Si薄膜太阳能电池的转化效率分别达到6.45%和5.1%,封装后电池组件具有一定的透光性,透光率约达到30.2%。     

共蒸发三步法制备CIGS薄膜的性质

采用PID温度控制器控制共蒸发设备中蒸发源及衬底加热的温度,以三步法工艺制备CIGS(Cu(In,Ga)Se2)薄膜,通过恒功率加热衬底测试温度的变化,可实现在线组分监测,得到CIGS薄膜的组成重现性很好.CIGS薄膜的表面光洁,粗糙度多数小于10nm.但是组成相同的CIGS薄膜,其结晶择优取向可能不同,主要有(112)和(220)/(204)两种;其结晶形貌也有很大的不同,晶粒粗大且成柱状的薄膜电池效率高,虽然从Cu/(In+Ga)＜1的组成可以认为CIGS薄膜为贫Cu结构,但Hall测试多数CIGS薄膜呈p型,少数呈n型.     

共蒸发三步法制备CIGS薄膜的性质

采用PID温度控制器控制共蒸发设备中蒸发源及衬底加热的温度,以三步法工艺制备CIGS(Cu(In,Ga)Se2)薄膜,通过恒功率加热衬底测试温度的变化,可实现在线组分监测,得到CIGS薄膜的组成重现性很好.CIGS薄膜的表面光洁,粗糙度多数小于10nm.但是组成相同的CIGS薄膜,其结晶择优取向可能不同,主要有(112)和(220)/(204)两种;其结晶形貌也有很大的不同,晶粒粗大且成柱状的薄膜电池效率高,虽然从Cu/(In Ga)＜1的组成可以认为CIGS薄膜为贫Cu结构,但Hall测试多数CIGS薄膜呈p型,少数呈n型.     

玻璃衬底上RF磁控溅射CIGS薄膜的研究

采用射频磁控溅射的工艺,在玻璃衬底上制备得到了铜铟镓硒(CIGS)薄膜。讨论了衬底温度、溅射气压、退火与否对CIGS薄膜与衬底结合力、显微形貌、晶化程度及电阻率的影响。通过能谱(EDS)测试证明了溅射的CIGS薄膜Ga组分比符合高效吸收层的要求,通过X射线衍射(XRD)与扫描电子显微镜(SEM)测试,证明了衬底加热溅射、溅射后450℃空气退火可以有效提高CIGS薄膜与衬底的结合并提高晶化程度。通过四探针法电阻率测试证明了低气压条件下溅射、溅射后退火可以有效降低CIGS的电阻率,通过透射光谱分析证明了CIGS薄膜对可见光有高吸收效率,适合作为太阳电池的高效吸收层。     

新型CIGS阻挡层多横向界面Mo的特性及对器件性能的影响

采用磁控溅射方法,在不锈钢箔上制备多横向界 面Mo(M-Mo,multi-transverse interface Mo)和单横向界面Mo(S-Mo)薄 膜,并利用共蒸发三步法分别在M-Mo和S-Mo薄膜上制备Cu(In,Ga)Se₂(CIGS)薄膜及 器件。通过二次离子质谱仪(SIMS)、X射线衍射仪(XRD)和扫描电子显微镜(SEM)研究了不同 结构的Mo薄膜对CIGS影响。通过I-V测试,表征M-Mo和S -Mo作为背电极的CIGS电池电学性能。XRD结果显示,M-Mo和S-Mo 薄膜均以(110)为择优取向。SEM结果显示,M-Mo薄膜相对 于S-Mo,薄膜晶粒 较小,粗糙度较大。J-V测试结果显示,M-Mo薄膜作为背 电极的电池的开路电压Voc、短路电流J sc和填充因子(FF)均有所提高。     

CdS薄膜的结构特性及其对Cu(In,Ga)Se2(CIGS)薄膜太阳电池的影响

报道了CdS薄膜的CBD法沉积及其结构特性,其中的水浴溶液包括硫脲、乙酸镉、乙酸铵和氨水溶液.研究了水浴溶液的pH值、温度、各反应物溶液的浓度和滴定硫脲与倾倒硫脲等基本工艺参数对CdS薄膜结构特性的影响.其中,溶液的pH值对CdS薄膜的特性起着关键的作用.XRD图显示了随着溶液pH值的变化,薄膜的晶相由六方相向立方相转变.CdS薄膜的这两种晶相对CIGS薄膜太阳电池性能的影响不相同.c-CdS(立方相的CdS)与CIGS之间的晶格失配和界面态密度分别为1.419%和8.507×1012cm-2,而h-CdS(六方相的CdS)与CIGS之间的晶格失配和界面态密度则分别为32.297%和2.792×1012cm-2.高效CIGS薄膜太阳电池需要的是立方相CdS薄膜.     

Morphology of CIGS thin films deposited by single-stage process and three-stage process at low temperature

Cu（In,Ga）Se2 （CIGS） thin films are prepared by a single-stage process and a three-stage process at low temperature in the co-evaporation equipment. The quite different morphologies of CIGS thin films deposited by two methods are characterized by scanning electron microscopy （SEM）. The orientation of CIGS thin films is identified by X-ray dif- fraction （XRD） and Raman spectrum, respectively. Through analyzing the film-forming mechanisms of two prepara- tion processes, we consider the cause of such differences is that the films deposited by three-stage process at low tem- perature evolve from Cu-poor to Cu-rich ones and then back to Cu-poor ones. The three-stage process at low tempera- ture results in the CIGS thin films with the （220）/（204） preferred orientation, and the ordered vacancy compound （OVC） layer is formed on the surface of the film. This study has great significance to large-scale industrial production.     

Preferred orientation of Cu(In,Ga)Se2 thin film deposited on stainless steel substrate

The influences of process parameters and Fe diffusing into Cu(In,Ga)Se₂ (CIGS) films on the orientation of CIGS absorbers grown on the stainless steel (SS) foils are investigated. The structural properties, morphology, and elemental profiles are characterized using X‐ray diffraction, scanning electron microscopy, and second ion mass spectroscopy, respectively. The orientation of CIGS thin films on the SS substrates strongly depends on the texture of the (In,Ga)₂Se₃ precursor, determined by the substrate temperature at the first stage (Ts1) and the flux ratio of Se to (In + Ga). Among these factors, Ts1 is the prerequisite to achieve [300]‐oriented IGS layer, which will yield [200]‐oriented CIGS thin film in the later process. The results indicate that through the comparison of CIGS thin films on the Mo/SS substrates and on the Mo/ZnO/SS substrates and combined with simply calculation, Fe diffusing into the CIGS layer will hinder the growth of the CIGS grains along [112] orientation. The grazing‐incidence X‐ray diffraction results suggest that the surface of the [220]‐textured CIGS thin film on the SS substrate still has [220] predominance, whereas the surface texture of the [220]‐texture CIGS thin film on the Mo/soda‐lime glass substrate became [112] predominant, which is due to the different compensation ability between Fe and Na elements. Finally, the relations between the device parameters and the degrees of the preferred orientation of CIGS absorbers are investigated. Copyright © 2012 John Wiley & Sons, Ltd.     

Cu(In,Ga)Se2太阳电池缓冲层ZnS薄膜性质及应用

在含有ZnSO4,SC(NH2)2,NH4OH的水溶液中采用CBD法沉积ZnS薄膜,XRF和热处理前后的XRD测试表明,ZnS沉积薄膜为立方相结构,薄膜含有非晶态的Zn(OH)2.光学透射谱测试表明,制备的薄膜透过率(λ＞500nm)约为90%,薄膜的禁带宽度约为3.51eV.ZnS薄膜沉积时间对Cu(In,Ga)Se2太阳电池影响显著,当薄膜沉积时间在25～35min时,电池的综合性能最好.对比了不同缓冲层的电池性能,采用CBD-CdS为缓冲层的电池转换效率、填充因子、开路电压稍高于CBD-ZnS为缓冲层的无镉电池,但无镉电池的短路电流密度高于前者,两者转换效率相差2%左右.ZnS可以作为CIGS电池的缓冲层,替代CdS,实现电池的无镉化.     

Fabrication of CIGS Films by Electrodeposition Method for Photovoltaic Cells

Cu(InGa)Se₂ (CIGS) thin films were fabricated by electrochemical deposition in a single bath containing Cu, In, Ga, and Se ions. The electrolyte was prepared by dissolving CuCl₂, InCl₃, GaCl₃, H₂SeO₃, and LiCl in deionized water. The potentiostatic deposition process was achieved by applying a voltage ranging from ?0.5?V to ?0.8?V versus Ag/AgCl. The effects of different chemical bath concentrations on the film composition and morphology were investigated. Stoichiometric CIGS film composition could be achieved by controlling the chemical compositions of the bath and the voltage. Gelatin was added to the solution to improve the surface and microstructures of the CIGS film. The as-deposited films were annealed at 500°C in Ar atmosphere for crystallization. The structural, morphological, and compositional properties of the CIGS thin films before and after annealing were examined by x-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. This study showed that the composition of the CIGS films is dependent on the bath concentration, whereas the applied potential had relatively less effect on the CIGS film composition. In addition, the use of gelatin helped in the fabrication of crack-free CIGS thin films with greatly improved surface morphology.     

铜含量变化对Cu(In,Ga)Se2薄膜微结构的影响

报道了不同的铜含量(Cu/(Ga+In)=0.748~0.982)对Cu(In,Ga)Se2 (CIGS)薄膜微结构的影响.文章中的CIGS薄膜采用磁控溅射金属预置层后硒化的方法制备, 其X射线衍射谱(XRD)中一系列黄铜矿结构CIGS(CH-CIGS)相的衍射峰确认了CH-CIGS相的存在.对CIGS薄膜拉曼光谱的分析表明, 随着铜含量的上升, CIGS薄膜经历了CH-CIGS和有序缺陷化合物(OVC)混合相、CH-CIGS单相、CH-CIGS和CuxSe混合相三种状态.进一步的分析显示, CIGS薄膜拉曼峰的半高宽随铜含量变化, 并在Cu/(Ga+In)=0.9附近时达到最小值, 这说明此时CIGS薄膜具有更好的结晶度和更少的无序性.此外还得到了CIGS薄膜拉曼峰半高宽与铜含量的经验关系公式.这些研究表明拉曼光谱能比XRD更加灵敏地探测CIGS薄膜的微结构, 可望作为一种无损和快速测量方法, 用于对CIGS薄膜晶相和铜含量的初步估计.     

Modification of deposition process for Cu(In, Ga)Se2 thin film solar cells on polyimide substrate at low temperature

We fabricate polycrystalline Cu(In, Ga)Se₂ (CIGS) film solar cells on polyimide (PI) substrate at temperature of 450 °C with single-stage process, and obtain a poor crystallization of CIGS films with several secondary phases in it. For improving it further, the two-stage process is adopted instead of the single-stage one. An extra Cu-rich CIGS layer with the thickness from 100 nm to 200 nm is grown on the substrate, and then another Cu-poor CIGS film with thickness of 1.5–2.0 μm is deposited on it. With the modification of the evaporation process, the grain size of absorber layer is increased, and the additional secondary phases almost disappear. Accordingly, the overall device performance is improved, and the conversion efficiency is enhanced by about 20%.