Ga源温度对共蒸发三步法制备Cu(In,Ga)Se2太阳电池的影响

利用共蒸发三步法制备了Cu(In,Ga)Se2(CIGS)薄膜,并通过调整制备工艺中的一、三步的金属镓(Ga)的温度,改变Ga含量的梯度分布,研究不同梯度分布对CIGS薄膜及电池性能的影响.从而优化了电池带隙梯度分布,使电池的开路电压Voc在提高的同时,最大程度的减小了Jsc的损失.优化后薄膜表面的结晶情况得到改善,电池的结界面和二极管特性也得到相应的提高.量子效率测试发现,优化后的CIGS太阳电池在较长波段中(520～1100nm)的光子吸收损失大大减小.     

Cu(In,Ga)Se2薄膜太阳电池二极管特性的研究

本文采用线性拟合光态和暗态J-V(电流-电压)曲线的方法计算了不同效率的Cu(In,Ga)Se2(CIGS)薄膜太阳电池的二极管性能参数.在一定范围内,CIGS薄膜电池的二极管品质因子A和反向饱和电流J0值越小,电池的转换效率越高,这说明CIGS电池的复合主要发生在PN结区内.量子效率分析表明,不同效率的CIGS电池在短波区(λ<520 nm)的光谱响应相差不大,而在长波区(520～1100 nm),低效率电池存在很大的吸收,这是由低质量的CIGS吸收层造成的.这进一步验证了光-暗态J-V曲线的分析结果,即高质量的吸收层是制备CIGS电池的关键.     

柠檬酸钠的浓度对电沉积制备Cu(In,Ga)Se2薄膜的影响

本文详细介绍了电沉积制备Cu(In,Ga)Se2(CIGS)薄膜的原理.电解液由CuCl2,InCl3,GaCl3和柠檬酸钠溶液组成.溶流组成通过改变柠檬酸钠的浓度,铟和镓的沉积电位接近或等于铜和硒的沉积电位.Cu(In,Ga)Se2薄膜的性能研究分别采用扫描电镜自带能谱仪(EDS)、X射线衍射(XRD)和扫描电镜分析Cu(In,Ga)Se2薄膜的化学组成、晶体结构和表面形貌.结果表明当柠檬酸钠浓度为1.0M时,所制备的Cu(In,Ga)Se2薄膜为单一的黄铜矿结构,晶粒大小均匀.     

多晶Cu(In,Ga)Se2薄膜太阳电池光强特性的研究

本文系统研究了Cu(In,Ga)Se2(CIGS)薄膜太阳电池在入射光强为10～100 mW/cm2范围内的性能参数.结果表明,随光强的减弱,CIGS电池的转换效率、填充因子、短路电流密度和开路电压等性能参数逐步衰减;电池参数与光强的依赖关系可明显划分为两个阶段:光强高于75 mW/cm2时,电池性能变化不大;当光强低于70 mW/cm2时,电池性能衰减明显.这是由于随着光强的降低,RS(串联电阻)值和RSH(并联电阻)值都在升高.其中,RSH值的增大使得CIGS电池的弱光特性变好,但较小的RSH值并不能弥补RS所导致电池性能的衰退.最后,发现高Ga含量的CIGS薄膜电池(8.7;)比低Ga含量(6.9;)的电池弱光特性好.     

Cu(In,Ga)Se_2薄膜表面镓(Ga)含量分布对太阳电池性能的影响

本文利用三步法共蒸发制备Cu(In,Ga)Se_2多晶薄膜吸收层,通过改变第三步Ga的蒸发温度控制薄膜表面Ga的含量及其分布.随着吸收层表面Ga含量的增大,空间电荷区带隙变宽,电池的开路电压V_(oc)明显增大.同时,Ga的梯度分布有效地扩宽了吸收层的光谱响应范围,减小了由于禁带宽度增大所引起的短路电流J_(sc)的损失,从而有效地提高了电池的转换效率.     

CIGS薄膜太阳电池异质结的结构初析

本论文通过实验制备得到CuIn0.7Ga0.3Se2(CIGS)、CdS、ZnO三种半导体材料,然后根据这三种半导体的相关材料参数和实验数据,得出了它们形成异质结前后的能带图,并计算它们的能带边失调值ΔEC、ΔEV.其中,CdS/CIGS的导带边失调值ΔEc对高效率CIGS薄膜太阳电池的影响作用最大,为-0.298eV(高效电池的理想值范围为0～0.4eV),说明这对电池整体性能不是很好.     

镓(Ga)的含量及分布对CIGS薄膜电池量子效率的影响

采用两步法制备CuGaxIn1-xSe2薄膜,Cu-In-Ga金属预制层采用铜镓合金靶及铟靶通过磁控溅射方法沉积而成,采用固态源硒化法在硒蒸气密闭环境中硒化,通过调整镓(Ga)比例及分布控制CIGS薄膜的带隙,采用镓元素梯度分布,使CIGS薄膜带隙呈现抛物线状分布,电池的量子效率得到明显提高,制备出的CIGS薄膜电池开路电压与转换效率都得到很大程度的改善,电池最高转换效率已达9.4;.     

单质靶溅射制备CZTS薄膜及太阳电池

采用单质靶磁控溅射制备Cu2ZnSnS4 (CZTS)薄膜,研究了薄膜的元素组分、升温速率、硫化温度对薄膜表面平整性以及晶粒尺寸的影响.通过SEM与AFM表征薄膜的表面形貌与表面粗糙度,用EDS检测薄膜的元素组分.所制备的样品的Cu/(Zn+ Sn)、Zn/Sn处于最优范围.通过XRD及Raman检测薄膜的结晶情况以及薄膜中的二次相,经上述测试分析判定CZTS薄膜品质良好.最终制备出以CZTS为吸收层的薄膜太阳电池,并用Ⅰ～V特性检验了CZTS电池性能参数,得到效率为0.83;的CZTS薄膜太阳电池,并通过改进硫化退火工艺将效率提高至1.58;.     

CIGS薄膜太阳电池产业化的最新进展及发展趋势

Cu(In,Ga)Se2(CIGS)薄膜太阳电池已经进入产业化快速发展阶段,显示出良好的发展趋势。本文就近年来CIGS薄膜太阳电池基础研究和产业化技术所取得重大突破性进展及产业化现状进行了概述。在基础研究方面,共蒸发法制备的小面积电池效率达到20.3%,非真空低成本涂覆法制备的电池效率达到17.1%。在产业化方面,商品化组件效率与小面积电池效率差距大幅度缩小,30 cm×30 cm电池组件效率达到17.8%,160 cm×66 cm大面积组件效率达到15.7%,产量和产能大幅增长。CIGS太阳电池产业化的技术路线很多,发展的重点各不相同,但最终也许会有一种解决方案集中所有技术的优点,成为产业化的主流,为未来世界能源供应和制造工业做出巨大贡献。     

卷对卷技术制备大面积柔性CIGS薄膜太阳电池吸收层

以轻质柔性聚酰亚胺(PI)材料为衬底,采用低温共蒸发"一步法"工艺制备四元化合物Cu(In,Ga)Se2(CIGS)薄膜.本文采用卷对卷(roll-to-roll)技术,在衬底幅宽300 mm的方向上实现了良好的成膜均匀性.利用XRD和XRF分别分析了所制备薄膜的晶相、组分和厚度,SEM分析了薄膜的表面形貌,讨论了不同衬底温度下制备的CIGS薄膜的性能.     

Relationship of Morphological Types of Dynamic Forms of Crystals

Crystallography Reports - The relationship of morphological spectra (sets of data on the morphological types of real polyhedral crystals and their probabilities under current physicochemical...     

Development of Pauling's concepts of geometric characteristics of atoms

The evolution of the geometric characteristics introduced by Pauling and their dependence on the specific features of the structure and chemical bonds have been considered. The values of the covalent and van der Waals radii are given as well as their relationships and mutual transitions.     

A review of measurement of thermophysical properties of silicon melt

Measurements of thermophysical properties of Si melt and supplementary study of X-ray scattering/diffraction by the authors' group were reviewed. The values obtained differed variously from those of literature. Density was 2–3% larger, surface tension 20–30% smaller, viscosity up to 40% larger, electrical conductivity 8% smaller, spectral emissivity more or less in good agreement with literature values, and thermal diffusivity a few percent larger. An anomalous density jump was found near the melting point. Surface tension and viscosity also showed anomaly. A strange time-dependent change of density was observed over 3 h after melting. X-ray analyses suggested a slight change in local atom ordering, but showed no sign of cluster formation. An addition of 0.1 at% gallium caused the density jump to disappear, while that of boron caused no change. An EXAFS study of the former melt indicated a strong interaction between Ga and Si atoms as if molecules of GaSi₃ existed. The implications of the measured properties are a possibility of soft-turbulence in an Si melt in a relatively large crucible, a more complicated manner of intake of oxygen depleted molten Si from the free surface region to underneath the growing crystal, and a relaxation of the melt after melting arising from trapped gas species.     

Generation of crystal structures of heteromolecular compounds by the method of discrete modeling of packings

Within the method of discrete modeling of packings, an algorithm of generation of possible crystal structures of heteromolecular compounds containing two or three molecules in the primitive unit cell, one of which has an arbitrary shape and the other (two others) has a shape close to spherical, is proposed. On the basis of this algorithm, a software package for personal computers is developed. This package has been approved for a number of compounds, investigated previously by X-ray diffraction analysis. The results of generation of structures of five compounds—four organic salts (with one or two spherical anions) and one solvate—are represented.     

Investigation of the Mechanism of Influence of Stress Corrosion on the Development of Macroplastic Instabilities of Aluminum–Magnesium Alloy

Crystallography Reports - Macroscopic jumps of plastic deformation (few percent in amplitude) on creep curves of aluminum–magnesium alloy, caused by a local effect of concentrated solution of...     

Comparative analysis of two methods of calculation of the orientation of domain walls in ferroelastics

Two types of domain-wall equations are analyzed: the equations derived by the Sapriel method and the equations obtained by interface matching of the thermal-expansion tensor. It is shown that, for W-type domain walls, these methods yield the same equations. For W′-type domain walls, the equations obtained by different methods coincide for proper ferroelastics and differ for improper ferroelastics.     

Dependence of the parameters of equations of viscous flow on chemical composition of silicate melts

The temperature dependence of viscosity of silicate melts is discussed in the framework of the Avramov–Milchev (AM) equation. The composition is described by means of two parameters: the molar fraction, x, and the “lubricant fraction”, l. The molar fraction is the sum of the molar parts x_i of all oxides dissolved in SiO₂, the molar fraction of the latter being 1 ? x. It is shown that, with sufficient precision, two of the parameters of the AM equation can be presented as unique functions of the molar fraction. On the other hand, x is not sufficient to determine properly the reference temperature T_r , at which viscosity is η_r = 10¹³ [dPa.s]. Therefore, additional parameter, “lubricant fraction” l, is introduced. For each of the components, l_i is a product of molar part x_i and a specific dimensionless coefficient 0 ≤ k_i ≤ 1 accounting for the specific contribution of this component to the increased mobility of the system. It is demonstrated that, for l > 0, the reference temperature is related to the “lubricant fraction” l through the reference temperature T_r,SiO2 of pure SiO₂.     

Mechanism of thermal expansion of structural modifications of zinc pyrovanadate

Crystal chemical characteristics of the α and β modifications of Zn₂V₂O₇ are calculated based on in situ high-temperature X-ray measurements. The expansion of the structure is found to be strongly anisotropic up to the negative volumetric thermal expansion of the α-Zn₂V₂O₇ unit cell in the temperature range of 300–600°С, α _V =–17.94 × 10^–6 1/K. The transformations of the “hard” and “soft” sublattices with an increase temperature and at the phase transition are considered in detail. It is shown that the negative volumetric thermal expansion of α-Zn₂V₂O₇ is due to the degeneracy of the zigzag-like shape of zinc–oxygen columns at constant distances between their vertices.     

A SAXS study of kinetics of aggregation of silica sols

SAXS in situ experiments on the evolution of TMOS solutions during hydrolysis and polycondensation lead to power laws with scaling exponents ≈ 2. It is suggested that this could be the result of the polydispersity of the samples and that only an apparent fractal dimension can be obtained in this way. Kinetic studies tend to indicate that agglomeration in the sol is the result of a diffusion-controlled process.