薄膜厚度对ZnO∶Ga透明导电膜性能的影响

采用射频磁控溅射法在玻璃衬底上低温制备出镓掺杂氧化锌(ZnO∶Ga)透明导电膜,研究了薄膜的结构、电学和光学性质随薄膜厚度的变化关系。制备的ZnO∶Ga是具有六角纤锌矿结构的多晶薄膜,最佳择优取向为(002)方向。随着薄膜厚度的增加,衍射峰明显增强,晶粒增大。薄膜的最低电阻率为 3.9×10-4Ω·cm,在可见光范围内平均透过率达到了85%以上。     

四苯硼钠添加剂对背钝化太阳能电池铝电极性能的影响

采用不同含量的四苯硼钠(C_(24)H_(20)BNa)添加剂制备背钝化太阳能电池(PERC)用铝浆,将铝浆丝网印刷于背钝化太阳能电池硅片上,经过烧结后测试电性能。通过扫描电镜(SEM)和能谱分析(EDS)对局部背表面区域(LBSF)进行微观形貌观察。结果表明,在四苯硼钠用量为0.5%(wt,质量分数)条件下,背钝化太阳能电池片的开路电压为656mV,填充因子为79%,电阻值为81Ω,光电平均转化率最高达到20.3%。     

复合背接触层与背电极的匹配对CdTe太阳电池性能的影响

本文研究Ni和Au两种背电极在有、无ZnTe/ZnTeCu背接触层时对碲化镉太阳电池性能的影响及其机理.试验结果表明,在没有ZnTe/ZrTeCu复合背接触层时,Ni和Au相比,输入特性的填充因子(FF)较差,短路电流密度(Jsc)较大,转换效率(η)较低;在有zrTe复合背接触层时,Ni和Au相比,FF相差较小,而η因Jsc较大而较高.通过暗特性的测试,可以看到,在有了ZnTe复合背接触层以后,Ni作背电极的碲化镉太阳电池,其二极管因子(A)、暗饱和电流(Jo)和旁路电阻(Rsh)等三个参数降低的幅度都比Au作背电极的大.这和ZnTe复合背接触层使Ni背电极碲化镉太阳电池效率有更大提高是吻合的.分析表明,这主要是由于光生电流的增大导致了Jsc的增大.这样用Ni代替Au作背电极会带来降低成本和效率提高的双重改进.     

薄膜厚度和溅射功率对有机衬底上ZnO∶Ga薄膜应力的影响

在室温(RT)下,采用直流(DC)磁控溅射在聚碳酸酯(PC)衬底上制备Ga掺杂ZnO(GZO)薄膜。通过X射线衍射(XRD)与基片曲率方法研究薄膜的残余应力。提出并讨论了厚度和溅射功率对GZO薄膜的应力影响并证实所有薄膜的应力均是压缩应力。研究表明随着薄膜厚度的增加,外应力可以得到充分释放。而溅射功率的变化可以改变GZO薄膜的应力和晶粒尺寸。研究表明溅射功率在140W的条件下制备的厚度225nm薄膜具有最大的晶粒尺寸和最小的压缩应力。结果表明改变溅射参数,比如溅射功率和薄膜厚度,GZO薄膜能够有效地释放应力。     

功率和退火对磁控溅射生长ZnO∶Ga薄膜的影响

采用射频磁控溅射法在玻璃衬底上制备了ZnO∶Ga透明导电薄膜(GZO)。通过X射线衍射(XRD)、四探针电导率测试、紫外可见分光光度等表征方法研究了溅射功率对薄膜结晶特性及光电性能的影响。结果表明:当溅射功率180W时制备的GZO薄膜光电性能最优,方块电阻为9.8Ω/sq,电阻率为8.6×10-4Ω·cm,霍尔迁移率为12.5cm2/V·s,载流子浓度为5.8×1020cm-3,可见光透过率超过92%。另外,研究了最优制备条件下的GZO薄膜的高温稳定性,在氩气、氧气和真空气氛下分别对薄膜进行退火处理。结果表明,氩气退火的薄膜电学性能显著提高,是显著改善GZO薄膜性能的有效方法之一;氧气退火不利于薄膜的导电性;真空退火介于两者之间。     

薄膜厚度对ZnO:Ga透明导电膜性能的影响

采用射频磁控溅射法在玻璃衬底上低温制备出镓掺杂氧化锌(ZnOGa)透明导电膜,研究了薄膜的结构、电学和光学性质随薄膜厚度的变化关系.制备的ZnOGa是具有六角纤锌矿结构的多晶薄膜,最佳择优取向为(002)方向.随着薄膜厚度的增加,衍射峰明显增强,晶粒增大.薄膜的最低电阻率为3.9×10-4Ω·cm,在可见光范围内平均透过率达到了85%以上.     

溅射气压对磁控溅射Mo背电极层形貌与结构的影响

采用直流磁控溅射法在溅射气压为0.1~1.0Pa下制备了金属Mo膜。用扫描电子显微镜(SEM)和原子力显微镜(AFM)对单层Mo膜的表面、断面形貌和粗糙度进行了分析与表征;用X射线衍射(XRD)研究了气压对Mo膜晶粒尺寸和薄膜应力应变的影响;用SEM观察了双层和三层Mo背电极层的表面形貌。结果表明,溅射气压升高,表面颗粒由细长变得圆润,均方根粗糙度升高,其值介于1.32~4.81nm之间;Mo膜的晶粒尺寸随气压的升高而降低,其值介于27.2~11.7nm之间;溅射气压为0.2Pa和0.3Pa时制备的Mo膜显现为张应力;将双层Mo背电极表面制备0.7Pa的Mo层后,表面更加圆润,孔隙增多。     

锂离子电池多层复合电极结构研究进展

随着电动汽车的快速发展,人们对动力电池的能量密度和寿命等电化学性能有了更高的要求.正负极活性材料的改性和修饰、新型导电剂和黏结剂的应用以及电极组分的优化设计,能够有效提升锂离子电池的循环性能和倍率性能.然而,传统电极因其单层结构本身存在的活性涂层表面结构不稳定,内部存在极化现象等问题,在一定程度上限制了高负载电极在锂离子电池中性能的发挥.因此改善传统电极中的单层结构,是锂离子电池研究的重要方向.本文通过归纳分析多层复合电极结构的相关研究,总结出解决单层电极结构本身问题的三种方案,分别为增加电极表面结构稳定性,增加电极表面导电性以及调整电极内部组分分布增加电极内部结构稳定性.这三种方案分别具备各自的优势,通过整合分析其特点,本文对目前多层复合电极结构的研究现状进行了总结,为锂离子电池及其他体系电池的电极设计提供了新的方向和思路.     

光伏电池用背电极银浆的制备与性能研究

通过化学还原法制备了粒径均一的高分散超细球形银粉,粒径1～2μm,并研究了影响银粉制备的因素。以此银粉为基础,选择合适的组分,制备晶硅光伏电池用背电极银浆,并改善了配制工艺,节省了制备步骤。经过印刷、烧结后,测试了银浆的焊接拉力、电阻率及与铝浆的复合性,达到了工业生产应用的要求。     

修饰ZnO对钙钛矿电池性能的影响

ZnO表面的羟基会与CH₃NH₃PbI₃分子中的甲铵离子发生路易斯酸碱反应,因此本工作将针对ZnO对钙钛矿太阳能电池性能的影响及如何抑制CH₃NH₃PbI₃的分解进行研究。结果表明:Sn元素的掺杂能够有效减少ZnO表面羟基的量,从而抑制钙钛矿层的分解,起到保护作用。通过石墨烯对ZnO的包覆,减少了外露羟基的数量,避免其表面的羟基与CH₃NH₃PbI₃直接接触,从而减少路易斯酸碱反应的发生,起到保护钙钛矿层的作用。     

Effects of nanostructured back reflectors on the external quantum efficiency in thin film solar cells

Hydrogenated amorphous Si ( α-Si:H) is a promising material for photovoltaic applications due to its low cost, high abundance, long lifetime, and non-toxicity. We demonstrate a device designed to investigate the effect of nanostructured back reflectors on quantum efficiency in photovoltaic devices. We adopt a superstrate configuration so that we may use conventional industrial light trapping strategies for thin film solar cells as a reference for comparison. We controlled the nanostructure parameters via a wafer-scale self-assembly technique and systematically studied the relation between nanostructure size and photocurrent generation. The gain/loss transition at short wavelengths showed red-shifts with decreasing nanostructure scale. In the infrared region the nanostructured back reflector shows large photocurrent enhancement with a modified feature scale. This device geometry is a useful archetype for investigating absorption enhancement by nanostructures.     

Cr层厚度对Pd/Cr/Co多层膜光学性质的影响

本文利用磁控溅射的方法生长不同Cr插层厚度的Pd/Cr/Co多层膜,并利用椭偏仪对多层膜的光学常数进行测量.得到了入射光波长在250nm-850nm范围内多层膜的折射率、反射率、吸收系数以及复介电常数的曲线,在此数据的基础上分析了Cr插层厚度对多层膜光学参数的影响.     

Influence of working pressure on ZnO:Al films from tube targets for silicon thin film solar cells

Mid-frequency magnetron sputtering of aluminum doped zinc oxide films (ZnO:Al) from tube ceramic targets has been investigated for silicon based thin film solar cell applications. The influence of working pressure on structural, electrical, and optical properties of sputtered ZnO:Al films was studied. ZnO:Al thin films with a minimum resistivity of 3.4 × 10⁻⁴ Ω cm, high mobility of 50 cm²/Vs, and high optical transmission close to 90% in visible spectrum region were achieved. The surface texture of ZnO:Al films after a chemical etching step was investigated. A gradual increase in feature sizes (diameter and depth) was observed with increasing sputter pressure. Silicon based thin film solar cells were prepared using the etched ZnO:Al films as front contacts. Energy conversion efficiencies of up to 10.2% were obtained for amorphous/microcrystalline silicon tandem solar cells.     

The structure and photoluminescence properties of ZnO/SiC multilayer film on Si substrate

ZnO/SiC multilayer film has been fabricated on a Si (111) substrate with a silicon carbide (SiC) buffer layer using the RF (radio frequency)-magnetron technique with targets of a ceramic polycrystalline zinc oxide (ZnO) and a composite target of pure C plate with attached Si chips on the surface. The as-deposited films were annealed at a temperature range of 600–1000°C under nitrogen atmosphere. The structure and photoluminescence (PL) properties of the samples were measured using X-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy and PL spectrophotometry. By increasing the annealing temperature to 800°C, it is found that all the ZnO peaks have the strongest intensities, and the crystallinity of ZnO is more consistent on the SiC buffer layer. Further increase of the annealing temperature allows the ZnO and SiC layers to penetrate one another, which makes the interface between ZnO and SiC layer become more and more complicated, thus reduces the crystallinities of ZnO and SiC. The PL properties of a ZnO/SiC multilayer are investigated in detail. It is discovered that the PL intensities of these bands reach their maximum after being annealed at 800°C. The PL peaks shift with an increase in the annealing temperature, which is due to the ZnO and SiC layers penetrating reciprocally. This makes the interface more impacted and complicated, which induces band structure deformation resulting from lattice deformation.     

Texturing of the back reflector for light trapping enhancement in micromorph thin film solar cells

The effects of textured back reflectors on light trapping in a-Si:H/μc-Si:H tandem cells are investigated with textured ZnO:Ga (GZO) back contacts obtained by surface wet etching. It is observed that rough back reflectors in fabricated tandem solar cells increase the short circuit current density of the bottom cells by 8%, which is attributed to light-trapping improvement. It is shown that enhanced longer wavelength light trapping is mainly attributable to improved light scattering at the back side by comparing identical a-Si:H/μc-Si:H tandem solar cells, both with a GZO back reflector but only one with a textured back reflector. The effectiveness of the textured GZO back reflector is also demonstrated in a textured a-Si:H/μc-Si:H tandem cell with a bottom cell thickness of 2 μm, which showed higher conversion efficiency than the reference cell.     

太阳能电池背膜发展现状

太阳能作为一种绿色能源,得到了各国科学家的重视,并在太阳能电池领域得到了商业化和产业化。太阳能电池背膜是太阳能电池的重要组件,本文从目前中国的太阳能电池背膜技术现状出发,探索了中国的太阳能电池背膜发展之路。     

层数变化对ZnO/In2 O3多层膜微观结构及光电性能的影响

用直流磁控溅射和热氧化法在玻璃衬底上制备ZnO/In2O3透明导电多层膜,当总厚度一定时,调节溅射沉积的层数与相应各层膜的厚度,研究该多层膜微观结构、光学性能和电学性能的变化.XRD和SEM分析表明:随着溅射沉积层数的增加,In2O3衍射峰的强度不断地减弱,ZnO衍射峰出现了不同的晶面择优取向;多层膜表面的ZnO晶粒粒径变小,光洁度增加.四探针法方块电阻测试表明:低温热氧化时,ZnO/In2O3多层膜的方块电阻随层数的增加而上升;高温氧化时,ZnO/In2O3多层膜的方块电阻随层数的增加而下降.可见光光谱分析表明:随着溅射沉积层数的增加,ZnO/In2O3多薄膜在可见光区的平均透过率增大,透过率的峰值向短波方向偏移.     

磁控溅射制备染料敏化太阳能电池氮掺杂碳膜对电极

采用双极脉冲磁控溅射法制备氮掺杂碳膜并作为对电极应用在染料敏化太阳能电池(DSSC)中。研究了氮掺杂对碳膜的结构与性能的影响。用X射线光电子能谱(XPS)对氮掺杂碳膜进行薄膜表面元素分析,用四探针测试仪对氮掺杂碳膜的方块电阻进行测试,用扫描电镜对氮掺杂碳膜表面形貌进行分析。组装电池,用太阳光模拟器测试电池的光电转化率。研究结果表明,经过氮掺杂的碳膜,表面形貌致密,当N2的体积分数为30%时,薄膜中N元素含量为15.21%,薄膜的方块电阻为9.4Ω/□,电池的光电转化率为1.16%。     

Nano-structural properties of ZnO films for Si based heterojunction solar cells

Properties and structure of ZnO and ZnO:Al films deposited on c-Si, a-Si:H/Si and glass substrates are studied by various methods. The transmittance of the ZnO:Al was found to be higher when compared to ZnO, and the refractive index lower. X-ray photoelectron spectroscopy (XPS) shows that the screening efficiency in the presence of core holes is enhanced in the Al doped ZnO. The roughness of the ZnO:Al surfaces is strongly substrate dependent. With transmission electron microscopy (TEM) a 2-3 nm thick amorphous interfacial layer was observed independently of substrate and doping. Deposition of ZnO on a-Si:H substrate results in crystallization of the a-Si:H layer independently of Al doping.     

AlN/WAlN/W太阳能选择性吸收多层薄膜研究

采用全封闭磁场的非平衡态磁控溅射系统,以纯金属为靶材,制备了AlN/WAlN(多层)/W薄膜。X射线掠射(GID)、扫描电镜(SEM)以及分光光度计等测试手段分析薄膜的相结构、表面形貌以及吸收光谱等特性。结果表明,薄膜沉积设备性能稳定,W、Al靶材溅射率高。获得AlN/WAlN(多层)/W薄膜中各层薄膜表面质地都较均匀,且为多晶态或纳米晶薄膜。该结构膜系对波长在200～2000nm范围内的光波有较高的吸收效果,平均吸收率可达96%以上,吸收性能优异。