真空法制备铜锌锡硫硒薄膜太阳电池的研究进展

真空法具有沉积速率快、重复性高以及成膜质量高等优势,有望成为大规模生产铜锌锡硫硒(Cu₂ZnSn(S,Se)₄,CZTSSe)薄膜太阳电池的制备方法。主要介绍了热蒸发法、磁控溅射法和脉冲激光沉积法等三种沉积CZTSSe薄膜的方法,阐述了采用真空法制备CZTSSe薄膜太阳电池的研究进展,同时对各种方法的优化途径(如退火条件优化、掺杂、背接触改善等)进行对比分析。最后,阐明了真空法的潜在优势以及存在的问题,并对未来发展进行展望。     

ZnO纳米颗粒薄膜的制备及其光学特性

采用化学回流法制备了3种不同粒径的ZnO纳米颗粒,然后旋涂在ITO玻璃衬底上,形成样品a、b和c3种ZnO纳米颗粒薄膜.场发射扫描电子显微镜(FESEM)结果显示,3种样品晶粒都呈颗粒形状,形成的薄膜较平整,平均晶粒尺寸分别为(φ)5 nm、(φ)25 nm和(φ)40 nm.X线衍射(XRD)结果表明,ZnO纳米颗粒为多晶六方晶系纤锌矿结构.样品a、b在可见光区有很少的光吸收,在紫外光区有很强的吸收,而由于纳米颗粒的直径较大,样品c在紫外和可见光区都存在很强的吸收.室温下的光致发光谱表明,样品a有一个近带边(NBE)紫外发射峰和蓝光发射峰,样品b、c出现一很宽的深能级缺陷相关的可见光发光带,这说明3种薄膜都存在大量的本征缺陷.     

溶胶-凝胶非硫化法制备铜锌锡硫薄膜

采用溶胶-凝胶非硫化方法制备了表面平整、致密的铜锌锡硫薄膜.XRD及Raman分析表明制备的铜锌锡硫薄膜为锌黄锡矿结构.能谱分析表明所有薄膜均贫铜富锌贫硫.场发射扫描电子显微镜测得薄膜的厚度在0.7 μm左右.透射光谱表明随后退火温度的提高薄膜的光学带隙从2.13 eV减小到1.52 eV.     

垂直靶向脉冲激光沉积制备ZnO纳米薄膜

用一种新颖的制备纳米粒子与薄膜的垂直靶向脉冲激光沉积(VTPLD)方法,在室温及空气气氛下,于玻璃基底上成功地制备出ZnO纳米薄膜.用扫描电子显微镜(SEM)和X射线衍射(XRD)仪对ZnO纳米薄膜的表面形貌和结构进行了表征,用荧光光谱仪对薄膜的光致发光(PL)性能进行了测量.结果表明,当激光功率为13 W时,沉积出的粒子大小较均匀,尺寸在40 nm左右,且粒子排列呈现出一定方向性;当激光功率为21 W时,沉积的ZnO纳米薄膜图呈现出微纳米孔的连续薄膜.在玻璃基底上沉积的ZnO纳米薄膜有一主峰对应的(002)衍射晶面,表明ZnO纳米薄膜具有良好的c轴取向性.不同激光功率下沉积ZnO纳米薄膜经500 ℃热处理后的PL峰,其强度随激光能量而变化,最大发光波长位于412 nm.     

（英）硫代硫酸钠浓度对电沉积制备铜锌锡硫硒薄膜性质的影响

采用后硒化Cu-Zn-Sn-S电沉积预制层的方法制备了铜锌锡硫硒薄膜,其中Cu-Zn-Sn-S预制层是通过含有不同浓度的硫代硫酸钠电解液电沉积而成的.实验发现,硒化前后薄膜的性质与硫代硫酸钠浓度密切相关.SEM,EDS,XRD,Raman和透射光谱分析表明,当硫代硫酸钠的浓度为5 mM时,沉积的薄膜形貌平整,晶粒明显,组分贫锌,具有单一的铜锌锡硫硒结构,且其带隙为1.11 eV; 在浓度高于5 mM下沉积的薄膜形貌粗糙并产生杂相硒化锡; 在浓度低于5 mM下沉积的薄膜组分严重贫锌并生成大量的Cu2SnSe3.     

近距离升华法制备Bi催化纳米晶CdTe薄膜的表征

采用近距离升华法(Close-Spaced-Sublimation,CSS)引入Bi催化剂成功制备出了具有纳米线、近阵列排布的纳米棒等形貌的纳米晶CdTe薄膜.并利用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外可见分光光度计等研究了薄膜的结构、表面形貌和光学性能.讨论了CdTe纳米结构可能的生长机制.

Abstract：

Bi-catalyzed nanocrystalline CdTe films were prepared by close spaced sublimation (CSS) technique successfully.These nanocrystalline CdTe films had surface appearance of nanowires or a similar array arrangement nanorod.The structure,the surface topograph and the optical properties of these films were studied using X-ray diffraction(XRD),scanning electron microscopy(SEM) and ultroviolet-visible (UV-VIS) spectrophotometer.And the possible growth mechanisms of these nanostructures were discussed.     

激光诱导银纳米颗粒薄膜和微结构

利用可见激光诱导化学沉积方法在玻璃基底上制备纳米银薄膜和微结构。玻璃样品池中装满柠檬酸钠和硝酸银的混合透明溶液,当一束可见连续激光正入射样品池一段时间后,在辐照区域的玻璃内壁上便可以形成一层光亮的银膜。银膜沉积的速度受到激光功率密度、激光波长、辐照时间以及混合溶液的浓度等条件的影响。利用X射线衍射、原子力显微镜和拉曼光谱仪等手段对制备的薄膜的成分、表面形貌和拉曼活性等性质进行了表征和分析。利用此方法制备的银膜具有良好的表面增强拉曼散射活性。同时,利用双光束干涉的方法在玻璃基底上诱导出不同周期的银纳米颗粒光栅。     

铝纳米薄膜对铜纳米薄膜的防护作用

铜纳米薄膜在微电子器件中应用广泛。然而,纳米尺度的铜表面极易发生氧化,影响铜纳米薄膜的电学性能。利用物理气相沉积方法制备了铜纳米薄膜,研究了基底粗糙度对铜纳米薄膜电学性能退化的影响,发现基底粗糙度越大,铜的电学性能退化越快。通过在铜纳米薄膜的表面蒸镀铝纳米薄膜对铜纳米薄膜进行防护,研究了铝纳米薄膜厚度对其在不同环境下防护效果的影响,结果显示铝膜厚度越大,对铜纳米薄膜的防护效果越好。通过高温破坏测试,发现铝纳米薄膜能有效地提高铜纳米薄膜的极限工作温度,当铝纳米薄膜厚度为10 nm时,可将铜纳米薄膜的极限工作温度提高2.5倍。     

玻璃基底/Ag纳米薄膜/聚苯胺电致变色薄膜的制备

采用垂直靶向脉冲激光沉积(VTPLD)法,在室温及 Ar气环境下于玻璃基底 上沉积Ag纳米薄膜。在Ag纳米薄膜上用提拉法获得一层聚苯胺(PANI)电致变 色薄膜。采用X射线衍射(XRD)、扫描电镜(SEM)和数字万用表考察激光功率对沉 积的Ag纳米薄膜的晶型结构、表面形貌和电导率的影响。采用循环伏安法、紫外 可见漫反射光谱法对不同激光功率下沉积的Ag纳米薄膜上PANI薄膜的电致变色 性能、结构变化进行分析。XRD和SEM结果显示,在玻璃基底上成功地获得粒径 为30～50nm的Ag纳米薄膜且其电阻值为1～5 Ω。在实验的最优条件 下,激光功率为17W时获得的Ag纳米薄膜致密均匀、结晶好和电阻值 较小;在优化的玻璃基底/Ag纳米薄膜上附着的PANI薄膜,电致变色电压最低、红移范围明 显。     

Na-Bi共掺对Cu2ZnSnS4薄膜性能的影响

Cu₂ZnSnS₄(CZTS)薄膜因其元素储量高、较佳的光学带隙、优异的电学性能等优势而得到广泛关注。以硝酸铋为铋源、乙酸钠为钠源,采用溶胶-凝胶法制备Na-Bi掺杂的CZTS薄膜。研究Na-Bi共掺对CZTS薄膜的物相结构、微观形貌、光学性能以及光电性能的影响。结果表明,制备的薄膜为锌黄锡矿结构。Na和Bi元素的掺入对薄膜的微观形貌影响较大。固定Na的原子数分数为1%,随着Bi元素原子数分数的增加,薄膜的晶粒尺寸先增大后减小,均匀性逐渐提高,光敏性先增大后减小,光学带隙逐渐增大。当Na和Bi原子数分数分别为1%和0.5%时,薄膜的光学带隙为1.42 eV,光敏性最佳为1.17。     

Cu2ZnSnS4 thin film solar cells by fast coevaporation

Solar cells based on kesterite‐type Cu₂ZnSnS₄ (CZTS) were fabricated on molybdenum coated soda lime glass by evaporation using ZnS, Sn, Cu, and S sources. The coevaporation process was performed at a nominal substrate temperature of 550°C and at a sulfur partial pressure of 2–3 × 10⁻³ Pa leading to polycrystalline CZTS thin films with promising electronic properties. The CZTS absorber layers were grown copper‐rich, requiring a KCN etch step to remove excess copper sulfide. The compositional ratios as determined by energy‐dispersive X‐ray spectroscopy (EDX) after the KCN etch are Cu/(Zn + Sn): 1.0 and Zn/Sn: 1.0. A solar cell with an efficiency of 4.1% and an open‐circuit voltage of 541 mV was obtained. Copyright © 2010 John Wiley & Sons, Ltd.     

Rapid annealing of reactively sputtered precursors for Cu2ZnSnS4 solar cells

Cu₂ZnSnS₄ (CZTS) is a promising thin‐film absorber material that presents some interesting challenges in fabrication when compared with Cu(In,Ga)Se₂. We introduce a two‐step process for fabrication of CZTS films, involving reactive sputtering of a Cu‐Zn‐Sn‐S precursor followed by rapid annealing. X‐ray diffraction and Raman measurements of the sputtered precursor suggest that it is in a disordered, metastable CZTS phase, similar to the high‐temperature cubic modification reported for CZTS. A few minutes of annealing at 550 °C are sufficient to produce crystalline CZTS films with grain sizes in the micrometer range. The first reported device using this approach has an AM1.5 efficiency of 4.6%, with J_sc and V_oc both appearing to be limited by interface recombination. Copyright © 2012 John Wiley & Sons, Ltd.     

Device characteristics of a 10.1% hydrazine‐processed Cu2ZnSn(Se,S)4 solar cell

A power conversion efficiency record of 10.1% was achieved for kesterite absorbers, using a Cu₂ZnSn(Se,S)₄ thin‐film solar cell made by hydrazine‐based solution processing. Key device characteristics were compiled, including light/dark J–V, quantum efficiency, temperature dependence of V_oc and series resistance, photoluminescence, and capacitance spectroscopy, providing important insight into how the devices compare with high‐performance Cu(In,Ga)Se₂. The record kesterite device was shown to be primarily limited by interface recombination, minority carrier lifetime, and series resistance. The new level of device performance points to the significant promise of the kesterites as an emerging and commercially interesting thin‐film technology. Copyright © 2011 John Wiley & Sons, Ltd.     

Electrodeposited Cu2ZnSnSe4 thin film solar cell with 7% power conversion efficiency

High performance Cu₂ZnSnSe₄ (CZTSe) photovoltaic materials were synthesized by electrodeposition of metal stack precursors followed by selenization. A champion solar cell with 7.0% efficiency is demonstrated. This is the highest efficiency among all of the CZTSe solar cells prepared from electrodeposited metallic precursors reported to‐date. Device parameters are discussed from the perspective of material microstructure and composition in order to improve performance. In addition, a high performance electrodeposited CZTS (S only) solar cell was demonstrated and its device characteristics were compared against the CZTSe (Se only) cell. Using secondary ion mass spectrometry for the analysis of the chemical composition of the absorber layer, a higher concentration of oxygen in the electrodeposited absorber is thought to be the root cause of the lower performance of the electrodeposited CZTS or CZTSe solar cells with respect to a solar cell fabricated by evaporation. The grain boundary areas of Sn‐rich composition are thought to be responsible for the lower shunt resistance commonly observed in CZTSe devices. We measured the longest minority carrier lifetime of 18 ns among all reported kesterite devices. This work builds a good baseline for obtaining higher efficiency earth‐abundant solar cells, while it highlights electrodepositon as a low cost and feasible method for earth‐abundant thin film solar cell fabrication. Copyright © 2013 John Wiley & Sons, Ltd.     

LBL法制备Cu3SbS4薄膜

针对水溶液化学沉积法沉积过程复杂且难于控制的缺点,利用LBL(layer-by-layer)法,在玻璃基片上制备出了Cu3SbS4薄膜。即首先在玻璃基片上沉积Sb2S3薄膜,然后再在其上制备CuS薄膜,最后进行退火处理。探讨了薄膜的制备机理、生长速度、结构特性和光学特性。制备的薄膜为多晶Cu3SbS4(四方晶系)结构,厚度为344nm,直接光学带隙约为0.47eV。     

Cu2ZnSnSe4 thin film solar cells produced by selenisation of magnetron sputtered precursors

Polycrystalline thin films of Cu₂ZnSnSe₄ (CZTSe) were produced by selenisation of Cu(Zn,Sn) magnetron sputtered metallic precursors for solar cell applications. The p‐type CZTSe absorber films were found to crystallize in the stannite structure (a = 5·684 Å and c = 11·353 Å) with an electronic bandgap of 0·9 eV. Solar cells with the indium tin oxide structure (ITO)/ZnO/CdS/CZTSe/Mo were fabricated with device efficiencies up to 3·2% measured under standard AM1·5 illumination. Copyright © 2009 John Wiley & Sons, Ltd.     

射频磁控溅射法制备Cu_2ZnSnS_4薄膜

利用射频磁控溅射法在玻璃基片上制备了Cu2ZnSnS4(CZTS)薄膜,薄膜在室温下生长,再在Ar气氛中快速退火。通过X射线衍射、X射线电子能谱、原子力显微镜和吸收谱研究了退火温度对薄膜结构、组分、形貌和禁带宽度的影响。结果表明,所制备样品为Cu2ZnSnS4多晶薄膜,具有较强的沿(112)晶面择优取向生长的特点,薄膜组分均为富S贫Cu,样品表面形貌比较均匀。退火温度为350,400,450和500℃的薄膜样品的禁带宽度分别是1.49,1.53,1.51和1.46 eV。     

9.0% efficient Cu2ZnSn(S,Se)4 solar cells from selenized nanoparticle inks

Thin‐film solar cells using Cu₂ZnSn(S,Se)₄ absorber materials continue to attract increasing attention. The synthesis of kesterite Cu₂ZnSnS₄ nanoparticles by a modified method of hot injection is explained. Characterization of the nanoparticles by energy dispersive X‐ray spectroscopy, X‐ray diffraction, Raman, and transmission electron microscopy is presented and discussed. When suspended in an ink, coated, and processed into a device, the nanoparticles obtained by this synthesis achieve a total area (active area) efficiency of 9.0% (9.8%) using AM 1.5 illumination and light soaking. This improvement over the previous efficiency of 7.2% is attributed to the modified synthesis approach, as well as fine‐tuned conditions for selenizing the coated nanoparticles into a dense absorber layer. Copyright © 2014 John Wiley & Sons, Ltd.