基于不同溅射方法制备铜锌锡硫薄膜及太阳电池

采用共溅射及分步溅射方法在涂钼的钠钙玻璃衬底上分别形成金属预制层,先后在低温及高温下对金属预制层进行合金后硫化,制备了铜锌锡硫(Cu_2Zn SnS_4,CZTS)薄膜。研究了薄膜的晶体结构、表面和截面形貌、元素组分、薄膜中的相纯度及元素的化学状态。结果表明:共溅射预制层得到的CZTS薄膜的表面及截面形貌优于分步溅射预制层得到的CZTS薄膜。用紫外-可见分光光度计与Hall测试系统表征了CZTS薄膜的光电特性,发现在200℃退火15 h能有效降低CZTS薄膜的缺陷态密度,增加CZTS薄膜中的载流子迁移率和扩散系数。研究结果表明,采用共溅射制备CZTS薄膜太阳电池性能优于分步溅射法,且经过退火处理的CZTS薄膜制备的电池特性均得到有效提高。基于分步溅射法制备的CZTS吸收层制备的电池开路电压为722 m V,短路电流密度为11.2 mA/cm~2,最高转换效率为3.22%;基于共溅射法制备的CZTS吸收层制备的电池开路电压为637 m V,短路电流密为15.0 mA/cm~2,最高转换效率为3.88%。     

溶液法制备铜锌锡硫硒薄膜太阳能电池的研究进展

溶液法因其具有操作流程简单、材料利用率高以及成本低廉等潜在优势,被认为是一种很有发展前景和应用潜力的铜锌锡硫硒(Cu₂ZnSn(S,Se)₄,CZTSSe)薄膜太阳能电池制备方法。本工作将溶液法的研究现状按喷雾热解法、基于浴的水溶液法、纳米粒子溶液法和直接溶液涂膜法进行分类介绍。通过分析和比较各种方法报道过的优化途径(如优化阳离子比例、烧结条件和硒化条件,以及掺入Na、Ge等金属元素),对溶液法制备的高性能Cu₂ZnSn(S,Se)₄薄膜太阳能电池的当前研究成果进行综述,并总结了各种溶液法制备铜锌锡硫硒薄膜电池的优势和所存在的问题。展望其未来的发展,认为今后的研究重点应侧重于薄膜组成和反应途径,以寻求降低Cu₂ZnSn(S,Se)₄吸收层的本征缺陷的方法。     

水热法制备铜锌锡硫纳米材料及其光催化性能

铜锌锡硫（Cu₂ZnSnS₄）在可见光范围内光吸收系数高且具有良好的载流子迁移率,使其在光催化领域表现出了较好的应用前景。然而在实际应用中,其光催化活性及催化稳定性还需进一步提升。以氯化锌、氯化锡、氯化铜、硫脲为水热反应前驱体,添加 PEG400、OP10 为表面活性剂,通过水热反应制备 Cu₂ZnSnS₄ （CZTS）纳米粉体;使用 X 射线衍射、Raman 光谱、X 射线光电子能谱、扫描电子显微镜、透射电子显微镜等手段表征所制备铜锌锡硫材料微观结构,并研究在水热法制备过程中添加不同表面活性剂对所制备 Cu₂ZnSnS₄纳米粉体的光学带隙和光催化性能的影响。结果表明：所制备铜锌锡硫材料均具有锌黄锡矿相结构;水热法制备铜锌锡硫纳米粉体反应前驱体中添加 PEG400 和 OP10 可有效调控铜锌锡硫纳米粉体的微观结构、化学元素计量比及光学带隙,进而改变纳米粉体的光催化性能。添加 PEG400 后制备得到 Cu₂ZnSnS₄     

铜锌锡硫光电转换材料性能及溶液 化学制备方法研究

铜锌锡硫（CZTS）具有资源丰富、环境友好、理论光电转换效率高等优点,是理想的薄膜太阳能电池光吸收材料。介绍了CZTS晶体结构和光电转换性能。综述了溶胶-凝胶前驱体法、溶剂（水）热法、热注入法、电沉积法、溶液法等溶液化学方法在CZTS材料制备及其薄膜太阳能电池的研究进展,讨论了目前存在的问题,并指出今后的研究方向。     

电沉积制备太阳能电池吸收层铜锌锡硫薄膜

以硫酸铜、硫酸锌、硫酸亚锡、硫代硫酸钠、柠檬酸钠为电解质,采用电沉积法在FTO导电玻璃上制备Cu/Zn/Sn/S前驱物,热处理后获得铜锌锡硫(Cu_2ZnSnS_4,CZTS)薄膜。通过单因素试验优化了镀液组成、pH值、沉积电位、沉积时间,得到了最佳的CZTS薄膜,其结晶性好,禁带宽度为1.55eV。它与ZnO缓冲层组装太阳能电池,光电转换效率最高为1.5×10~(-2)%。     

电沉积制备铜系薄膜太阳能电池吸收层的研究现状

介绍了一步沉积法和多步沉积法制备铜铟硒(CISe)、铜铟硫(CIS)、铜铟镓硒(CIGS)、铜锌锡硫(CZTS)等铜系薄膜太阳能电池吸收层的电沉积技术,并对其未来发展进行了展望。     

磁控溅射法制备铜锌锡硫薄膜电池

采用磁控溅射法,先在镀钼的钠钙玻璃衬底上共溅射Cu、Sn金属层后,然后在顶部溅射一层Zn S,制备出Cu_2ZnSnS_4(CZTS)薄膜的预制层。对预制层进行低温合金,然后以硫粉作为硫源在石英管中进行高温硫化,得到表面平整但晶粒较小的CZTS薄膜。通过X射线衍射仪(XRD)、扫描电镜(SEM)及能谱仪(EDS)分别对薄膜的晶体结构、表面形貌和薄膜组分进行分析表征;并用拉曼光谱表征了CZTS相的纯度。最后用所得到的CZTS薄膜制备了太阳电池,其开路电压:Voc=442 m V,短路电流密度:Jsc=5.08 m A/cm~2,光电转换效率达到0.62%。     

日美开发转换率达12.6%的CZTS太阳能电池

<正>日前,日本薄膜组件制造商Solar Frontier公司对外宣布,他们与美国IBM公司、东京应化工业公司(東京応化工業株式会社)合作开发的铜锌锡硫(CZTS)太阳能电池(见图1)转化率达到了世界最高水平12.6%,打破了该公司同类产品于2012年创下的11.1%转化率的纪录。研究小组通过改良Cu2ZnSnSx Se4-x(CZTSSe)光吸收层、改进光学结构等,使CZTS太阳能电池的转换率显著提高。     

制备方法对钙钛矿薄膜结构及形貌的影响

采用液相连续沉积法制备了有机/无机杂化钙钛矿（CH₃NH₃PbI₃,MAPbI₃）光吸收层,并研究了不同薄膜形貌、晶体结构和光吸收能力对钙钛矿太阳能电池性能的影响。结果表明：制备工艺对吸光层形貌和器件光电性能产生很大的影响。相对于分步浸渍法,分步旋涂法（分步旋涂无机相碘化铅PbI₂和有机相甲胺碘CH₃NH₃I前驱液）和气体辅助修复法（新制初始MAPbI₃薄膜在室温下置于甲胺气氛中）能有效改善薄膜形貌和平整度,获得覆盖完全的均匀钙钛矿吸光层。同时,进一步分析了初始MAPbI₃膜的形貌对气体修复法制备全覆盖平整钙钛矿薄膜的影响,发现初始钙钛矿膜的形貌对最终修复后的膜层形貌没有影响,这可能是因为不同初始MAPbI₃膜经甲胺气体处理后均形成一种"甲胺铅化碘-甲胺"（MAPbI₃·MA）的液态中间相,再经退火处理后均获得平整、致密的钙钛矿膜层,极大地提高了MAPbI₃的结晶度和薄膜均匀性,从而提高活性层的吸光率、光电流和电池效率。     

电化学法制备Cu_2ZnSnS_4薄膜及其特性研究

采用两电极的电化学沉积方在钼衬底上制备了Cu_2ZnSnS_4(CZTS)薄膜。将Cu、Zn、Sn三种金属元素按一定的顺序分步沉积在钼片上得到CZT薄膜前驱体把预制层放置在S的气氛中并在N_2的保护下退火硫化得到CZTS薄膜。通过SEM、EDS、XRD分析了CZTS薄膜的表面形貌、元素组分、结晶情况,并用拉曼光谱进一步确定了薄膜的晶体成分。最后将CZTS薄膜经过后步工艺制作成CZTS薄膜太阳电池,并通过Ⅰ-Ⅴ测试得到了该电池的效率及其它相应参数。     

Flexible CZTSSe thin film solar cells fabricated at low temperature with relieved residual stress by Sb incorporation

The troublesome residual stress is always a stumbling block that drags the progress pace of flexible CZTSSe thin film solar cells, which urgently needs to be noticed and solved. In this paper, low-temperature prepared CZTSSe absorber with relieved residual stress (0.558 GPa) is realized by Sb incorporation. Owing to the evaporated 20 nm Sb layer under CZTS precursor, the crystalline quality and band mismatching of CZTSSe/CdS interface are simultaneously improved. Additionally, the spatial potential fluctuation extracted from the PL results is found to decrease from 63.26 meV to 41.57 meV, indicating a reduction in band tailing and disorder of CZTSSe absorber. Compared with the general solar cells fabricated at 580 °C, flexible devices with Sb incorporation can maintain a slightly higher performance at a lower temperature about 60 °C. The best power conversion efficiency (PCE) of 4.41% is obtained in the solar cell with 550 °C-selenized CZTSSe absorber after incorporating 20 nm Sb layer, featuring 351.20 mV Voc, 25.73 mA/cm² Jsc and 48.79% FF. Finally, low-temperature prepared flexible CZTSSe thin film solar cell can retain over 83% of the original PCE after bending at 180° for 40 cycles. The mechanical durability paves a promising way for flexible CZTSSe thin film solar cell in roll-to-roll production.     

Preparation and Characterization of Sol—Gel-Derived Lead Magnesium Niobium Titanate Thin Films with Pure Perovskite Phase and Lead Oxide Cover Coat

A sol–gel-derived Pb(Mg_1/3Nb_2/3)_0.7Ti_0.3O₃ (PMNT) thin film was prepared using spin coating and a PbO cover coat technique. The amount of lead excess in the precursor solution had significant effects on the phase development and microstructure of the PMNT film. The PbO cover coat proved to be effective on suppressing the formation of pyrochlore phases. PMNT thin films with a pure perovskite structure were obtained by adding 30 mol% excess lead in the precursor solution and coating the PbO layer on the top of the film. The remnant polarization ( P _r), the dielectric constant (ɛ_r), and the dissipation factor (tan δ) of these thin films, which had a thickness of 150 nm, were determined to be 9 μC/cm², 1370, and 0.031, respectively.     

Impact of SnS Buffer Layer at Mo/Cu2ZnSnS4 Interface

Cu₂ZnSnS₄ (CZTS) compound is a promising candidate for thin‐film solar cells since its constituents are earth abundant and nontoxic. One of the major challenges to obtain a high‐quality CZTS absorber is to overcome the interfacial mismatch and formation of secondary phases between the CZTS and Mo substrate during the sulfurization process. Generally, the CZTS decomposed into Cu₂S, ZnS, and SnS phases during sulfurization, and high‐density voids and cracks were observed. These micro‐ or macroreactions changed the stoichiometry of CZTS. In this paper, we present the insertion of a SnS buffer layer at Mo/CZTS interface to inhibit the undesired reaction and improve the thin‐film quality. The insertion of the thin SnS buffer layer prevented the CZTS absorber to contact directly with Mo and suppressed the present of secondary phases, pores and cracks. Crack‐free and smooth morphology was obtained. The cell efficiency was significantly improved.     

A new method for measuring wetness of flowing steam based on surface plasmon resonance

Stacked precursors of Cu-Zn-Sn-S were grown by radio frequency sputtering and annealed in a furnace with Se metals to form thin-film solar cell materials of Cu₂ZnSn(S,Se)₄ (CZTSSe). The samples have different absorber layer thickness of 1 to 2 μm and show conversion efficiencies up to 8.06%. Conductive atomic force microscopy and Kelvin probe force microscopy were used to explore the local electrical properties of the surface of CZTSSe thin films. The high-efficiency CZTSSe thin film exhibits significantly positive bending of surface potential around the grain boundaries. Dominant current paths along the grain boundaries are also observed. The surface electrical parameters of potential and current lead to potential solar cell applications using CZTSSe thin films, which may be an alternative choice of Cu(In,Ga)Se₂. PACS number: 08.37.-d; 61.72.Mm; 71.35.-y     

Nanoscale observation of surface potential and carrier transport in Cu2ZnSn(S,Se)4 thin films grown by sputtering-based two-step process

Stacked precursors of Cu-Zn-Sn-S were grown by radio frequency sputtering and annealed in a furnace with Se metals to form thin-film solar cell materials of Cu₂ZnSn(S,Se)₄ (CZTSSe). The samples have different absorber layer thickness of 1 to 2 μm and show conversion efficiencies up to 8.06%. Conductive atomic force microscopy and Kelvin probe force microscopy were used to explore the local electrical properties of the surface of CZTSSe thin films. The high-efficiency CZTSSe thin film exhibits significantly positive bending of surface potential around the grain boundaries. Dominant current paths along the grain boundaries are also observed. The surface electrical parameters of potential and current lead to potential solar cell applications using CZTSSe thin films, which may be an alternative choice of Cu(In,Ga)Se₂.PACS number: 08.37.-d; 61.72.Mm; 71.35.-y     

Structural,optical and electrical properties of indium doped Cu2ZnSn(S,Se)4 thin films synthesized by the DC and RF reactive magnetron cosputtering

Element doping into the Cu₂ZnSn(S,Se)₄ (CZTSSe) absorber is an effective method to optimize the performance of thin film solar cells. In this study, the Cu₂In_xZn_1-xSn(S,Se)₄ (CIZTSSe) precursor film was deposited by magnetron cosputtering technique using indium (In) and quaternary Cu₂ZnSnS₄ (CZTS) as targets. Meanwhile, the In content was controlled using the direct current (DC) power on In target (P_In). A single kesterite CIZTSSe alloy was formed by successfully doping a small number of In³⁺ into the main lattice of CZTSSe. The partial Zn²⁺ cations were substituted by In³⁺ ions, resulting in improving properties of CZTSSe films. Morphological analysis showed that large grain CIZTSSe films could be obtained by doping In. The well-distributed, smooth, and dense film was obtained when the P_In was 30 W. The band gap of CIZTSSe could be continuously adjusted from 1.27 to 1.05 eV as P_In increased from 0 to 40 W. In addition, the CIZTSSe alloy thin film at P_In = 30 W exhibited the best p-type conductivity with Hall mobility of 6.87 cm²V^?1s^?1, which is a potential material as the absorption layer of high-performance solar cells.     

Effects of ethyl acetate additive on Cu2ZnSnS4 solar cells fabricated with a facile dimethylformamide-based solution coating process

The solution based on dimethylformamide (DMF) has shown promising application prospects in the fabrication of high-efficiency Cu₂ZnSnS₄ solar cells. However, due to the high boiling temperature of the solvent, it is difficult to completely volatilize DMF during the evaporation process after spin coating, leading to remains of C and O atoms at grain boundaries, which severely restricts the photoelectric performance of solar cells. In this study, ethyl acetate (EA) with green character was used as an additive to optimize the film formation process of DMF-based CZTS precursor. The experimental results showed that using a small amount of EA additives could effectively improve morphology, crystallinity, composition distribution and electrical properties of the CZTS absorber. In addition, the CZTS and CdS heterojunctions exhibited a cliff-like energy band structure, and the optimized conduction band offset increased the activation energy required for the carrier recombination path, consequently reducing the carrier recombination. Compared with the pure DMF precursor solution, the photoelectric conversion efficiency of CZTS solar cells with an EA addition ratio of 10% was improved by 42%, and the open circuit voltage of the device reached 601 mV.     

Effect of periodic precursor on sulfurization process of Cu2ZnSnS4 thin film

In this study, Cu₂ZnSnS₄ (CZTS) thin films were fabricated by periodically sequential depositions of metallic precursors by magnetron sputtering followed by sulfurization. The element compositions, crystal structures, and surface morphologies of the single-period precursor (Zn/Sn/Cu) and four-period precursor (Zn/Sn/Cu/Zn/Sn/Cu/Zn/Sn/Cu/Zn/Sn/Cu) during the sulfurization process were investigated. The experimental results showed that in the initial stage of sulfurization, the single-period precursor had a more efficient reaction with sulfur vapor below 300?°C because of its thicker metal layers. During the process of sulfurization, the CZTS phase first formed in the four-period film at 400?°C, owing to the wide distribution of the internal layer in the periodic thin film. With a further increase in temperature, the crystallinity of CZTS was enhanced and the secondary phases were reduced. A CZTS phase with Cu-poor and Zn-rich composition was confirmed in both thin films after complete sulfurization. The CZTS thin film with a four-period precursor showed a better degree of crystallization, and a single phase of CZTS was obtained more easily than in the single-period thin film. Therefore, using a periodic structure can promote the sulfurization reaction of Cu-Zn-Sn precursors and enhance the properties of CZTS thin films.     

Influence of H2Se concentration on Se-rich CZTSSe absorbers sputtered with a ceramic quaternary target

Se-rich CZTSSe absorbers with large grains are important contributors to the performances of CZTSSe solar cells and can be fabricated by the selenization of as-sputtered CZTS precursors. To explore the effects of the H₂Se concentration in the annealing atmosphere on the growth of CZTSSe phases, sputtered CZTS precursors were subjected to annealing with a mixed gas of Ar and H₂Se at different concentrations. A series of characterization techniques were employed to investigate the morphologies, phase structures, surface states, and elemental compositions of the annealed samples. The results demonstrate that the H₂Se concentration in the annealing atmosphere can significantly affect the grain size, suppressing the decomposition of CZTSSe absorbers. When the H₂Se concentration in the annealing atmosphere reaches 4.5 vol%, a selenium-enriched CZTSSe absorber that is composed of the pure kesterite structure and that has densely packed large grains and a high concentration of selenium was obtained. The highest efficiency of 10.12% of CZTSSe solar cells was achieved herein.