离子液体电沉积CuInxGa1-xSe2薄膜

采用循环伏安法(CV)对离子液体Reline中三元CuCl₂+InCl₃+SeCl₄体系和四元CuCl₂+InCl₃+GaCl₃+SeCl₄体系的电化学行为进行了研究。研究表明,In³⁺并入三元CIS(Cu-In-Se)薄膜体系和Ga³⁺并入四元CIGS(Cu-In-Ga-Se)薄膜体系均有两种途径：一是发生共沉积,二是直接还原。利用电感耦合等离子体发射光谱(ICP)和扫描电镜(SEM)对沉积电势、镀液温度和主盐浓度对CIGS薄膜组成、镀层表面形貌的影响进行了测试,结果表明通过工艺参数的选择可以控制Ga/(Ga+In)和CIGS薄膜组成并得到化学计量比为Cu_1.00In_0.78Ga_0.27Se_2.13的薄膜。     

Characteristic material parameters of CIGS solar cell related with device performance

CIGS solar cells with power conversion efficiency (PCE) in the range of 1.82%–12.30% were obtained by using two-step process, and were further analyzed through various measurement techniques. Material parameters showed diverse values and some trends depending on the device performance. The lower performance device showed small integrated PL intensity, short minority life time, larger defect density and lower activation energy, whereas the higher performance device showed opposite values. We investigated relationship between material parameters and PCE of solar cells, and found that some physical parameters such as integrated PL intensity, minority life time, defect density, and difference between band gap and activation energy (E_g-E_a), which all reflect defect states in bulk and at pn interface, are strongly related with PCE and would be used as a good indicator to evaluate device performance quickly.     

使用分子量级前躯体制备CuInSe_2及其合金并应应用用于光伏发电(英文)

黄铜矿铜铟硒化合物CuInSe2及其与硫或嫁的合金CuIn(Se,S)2或CuInGa(Se,S)2,即所说的CIGS,已通过20%的实验室规模器件光电转换效率展示了其地面光伏应用的巨大潜力。为了减少初始资金成本,提高材料利用率,科研工作者们已经尝试了许多努力通过非真空制程沉积CIGS。这些制程包括电镀工艺,基于颗粒(浆或纳米颗粒)的制程和基于分子量级前趋体的制程。原则上,分子量级前趋体可以使组分元素达到充分混合,可以最大程度地实现组份在基板不同区域的均一分布。这对于一个复杂的涉及到五个主要元素的化合物系统尤为重要。从这个角度来看,分子前趋体的方法具有大面积均匀沉积铜铟镓硒的巨大潜力。这篇综述将着重讨论使用分子前趋体沉积铜铟镓硒制程的最新发展。     

Molybdenum thin film deposited by in-line DC magnetron sputtering as a back contact for Cu(In,Ga)Se2 solar cells

In this paper, we reported the effect of the power and the working pressure on the molybdenum (Mo) films deposited using an in-line direct current (DC) magnetron sputtering system. The electrical and the structural properties of Mo film were improved by increasing DC power from 1 to 3 kW. On the other side, the resistivity of the Mo films became higher with the increasing working pressure. However, the adhesion property was improved when the working pressure was higher. In this work, in order to obtain an optimal Mo film as a back metal contact of Cu(In,Ga)Se₂ (CIGS) solar cells, a bilayer Mo film was formed through the different film structures depending on the working pressure. The first layer was formed at a high pressure of 12 mTorr for a better adhesion and the second layer was formed at a low pressure of 3 mTorr for a lower resistivity.     

预制层溅射气压对CIGS薄膜结构及器件的影响

研究了金属预制层制备过程中溅射气压对Cu(In_1-xGa_x)Se₂(CIGS)薄膜及电池器件性能的影响.通过调节溅射气压改变预制层的结晶状态及疏松度与粗糙度,在合适的预制层结构下,活性硒化热处理过程中,可使Ga有效地掺入到薄膜中形成优质的CIGS固溶体.高溅射气压会使预制层过于致密,呈现非晶态趋势.经活性硒化热处理后,CIGS薄膜容易产生CIS与CGS"两相分离"现象,从而导致CIGS薄膜太阳电池的开路电压和填充因子降低,电池转换效率由10.03%降低到5.02%.     

热裂解活化硒对CIGS太阳电池开路电压的影响

考察了通过自主研发的高温热裂解辅助硒化装置所产生的高活性硒对CIGS薄膜结构和器件性能的影响.通过调节高温裂解系统的温度可以有效调节不同的硒活性.研究发现, 第一台阶HC-Se气氛可以提高CIGS薄膜表面的Ga含量, 使得CIGS薄膜内的Ga分布更加平缓, 进而提高CIGS薄膜表面禁带宽度.而且HC-Se气氛可以消除CIGS"两相分离"现象.两种因素的共同作用使得CIGS薄膜太阳电池的开路电压提高了34.6%.电池转换效率从6.02%提升至8.76%, 增长了45.5%.     

直流磁控溅射厚度对Cu(Inx,Ga1-x)Se2背接触Mo薄膜性能的影响

采用直流磁控溅射工艺, 在一定条件下通过控制溅射时间, 在钠钙玻璃上制备了不同厚度的用于Cu(In_x, Ga_1-x)Se₂薄膜太阳电池背接触材料的Mo薄膜, 并利用X射线衍射 (XRD)、场发射扫描电子显微镜 (SEM)、四探针测试仪、台阶仪研究了厚度对溅射时间、薄膜微结构、电学性能及力学性能的交互影响. Mo薄膜的厚度与溅射时间呈线性递增关系; 随厚度的增大, Mo薄膜 (110) 和 (211) 面峰强均逐渐增大, 择优生长从(110)方向逐渐向 (211)方向转变, 方块电阻值只随 (110) 方向上的生长而急剧减小直到一特定值约2 Ω/⇑, 电导率随薄膜的 (110) 择优取向程度的降低而线性减小直到一特定值约0.96×10^-4 Ω·cm; Mo薄膜内部是一种多孔的长形簇状颗粒和颗粒间隙交织的结构, 并处于拉应力态, 其内部应变随薄膜厚度的增大而减小. 关键词： Mo薄膜 CIGS背接触 厚度 微结构     

Crystallization and surface segregation in CuIn0.7Ga0.3Se2 thin films on Cu foils grown by pulsed laser deposition

This work reports unexpected crystallization and segregation behavior of CuIn_0.7Ga_0.3Se₂ (CIGS) thin films deposited on flexible Cu foils by pulsed laser deposition. A composite-type microstructure containing nanometer-scaled CIGS crystallites embedded in amorphous Cu-rich matrix is observed even at the high temperature of 500 °C. The findings are attributed to very fast condensation of the ablated species and random nucleation induced from the amorphous matrix. Cu-rich particulates tend to precipitate on the film surface, and their average size, shape, number density and composition exhibit a strong dependence on the substrate temperature up to 500 °C. The similar crystallization properties of the films on Cu foils and glass substrates are noticeable to the use of Cu foils for flexible solar cells.     

Photovoltaic performance of flexible Cu(In,Ga)Se2 thin-film solar cells with varying Cr impurity barrier thickness

We report the effect of Cr impurity barrier on Cu(In,Ga)Se₂ (CIGS) thin-film solar cells prepared on flexible substrates. The Cr films with varying the thickness (t_Cr) were deposited on stainless steel substrates using direct-current magnetron sputtering. The solar cell performance was improved by increasing t_Cr since the diffusion of Fe impurities from the substrate to CIGS was suppressed. Although the elemental composition, grain size, and strain of CIGS film showed little change with varying Fe content, the fill factor and the short-circuit current density increased as decreasing Fe. The Fe increased the series resistance, shunt paths, and saturation current density. The reduction of Fe caused a steeper bandgap grading in CIGS which enhances current collection due to higher electric fields in bulk CIGS. CIGS solar cells with 1000 nm-thick Cr barrier showed the best conversion efficiency of 9.05%.