用于太阳电池吸收层的Cu2ZnSnS4薄膜的制备及其光电特性

采用真空蒸镀技术在钠钙玻璃衬底上蒸镀Cu/Sn/ZnS前驱体,在氮气保护下,硫化制备了Cu2ZnSnS4(CZTS)薄膜.运用X射线衍射仪(XRD)、Hall效应测试仪、紫外-可见光(UV-VIS)分光光度计对样品进行了表征分析,研究了前驱体中预计原子比对CZTS薄膜的晶体结构及光电特性的依赖关系.通过对蒸发源Cu的质量的控制与微调,获得了具有单一相类黝锡矿结构的CZTS薄膜,其对可见光的光吸收系数大于104cm-1、光学禁带宽度约为1.51eV,薄膜的电阻率、载流子迁移率和载流子浓度分别为1.46Ω·cm,4.2cm2/(V·s)和2.37×1018cm-3,适合作为薄膜太阳电池的吸收层.     

金属成分对固态硫化CZTS薄膜性能的影响北大核心

采用磁控溅射法制备铜锌锡(CZT)金属预制膜,再利用固态硫化法制备了Cu2ZnSnS4(CZTS)薄膜。研究了CZT金属预制膜中Sn的原子数分数对CZTS薄膜的化学成分、结构组织和光学性能的影响规律。结果表明:实验制备的CZT金属预制膜硫化后均能得到主相为CZTS的薄膜。在适当的范围内增加CZT金属预制膜中Sn的原子数分数可提高CZTS薄膜的结晶度,有利于生长均匀致密的CZTS薄膜;Sn的原子数分数过高时,硫化后制得的CZTS薄膜存在杂相Sn2S3。当CZT预制膜中各成分的原子数分数比为yZn/ySn=0.24,yCu/yZn+Sn=0.33时,固态硫化后可获得表面均匀致密、具单相的CZTS薄膜,该薄膜中yZn/ySn=1.15,yCu/yZn+Sn=0.92,光吸收系数达104 cm-1,光学带隙为1.52 eV。     

用于太阳电池吸收层的Cu2ZnSnS4薄膜的制备及其光电特性

采用真空蒸镀技术在钠钙玻璃衬底上蒸镀Cu/Sn/ZnS前驱体,在氮气保护下,硫化制备了Cu2ZnSnS4(CZTS)薄膜.运用X射线衍射仪(XRD)、Hall效应测试仪、紫外-可见光(UV-VIS)分光光度计对样品进行了表征分析,研究了前驱体中预计原子比对CZTS薄膜的晶体结构及光电特性的依赖关系.通过对蒸发源Cu的质量的控制与微调,获得了具有单一相类黝锡矿结构的CZTS薄膜,其对可见光的光吸收系数大于104cm-1、光学禁带宽度约为1.51eV,薄膜的电阻率、载流子迁移率和载流子浓度分别为1.46Ω·cm,4.2cm2/(V·s)和2.37×1018cm-3,适合作为薄膜太阳电池的吸收层.     

衬底温度对CZTSSe薄膜结构特性的影响

采用热蒸发法制备铟锌锡硫(CZTSSe)薄膜。采用低 温一步 法在300℃衬底温度下制备CZTSSe薄膜;采用两步法,即在衬底温度 分别为300℃制备CZTSSe 薄膜;将衬底温度设定为480℃不变,一步蒸发沉积CZTSSe薄膜。通 过对X射线衍射(XRD)、 扫描电镜(SEM)、拉曼谱对比发现,在300℃低温下一步法和300℃ 、480℃两 步法沉积的薄膜表面粗糙,碎小晶粒较多;在480℃一步高温法制备 的薄膜表面平整, 晶粒大小均匀,3个衍射峰的半高峰宽变窄,薄膜的结晶质量得到 改善,且没有发现其它杂相的拉曼特征峰,沉积出适合作为制备CZTSSe薄膜太阳电池的 吸收层。     

石英衬底上溅射制备纳米SiCN薄膜

利用射频溅射方法在石英玻璃上沉积了纳米结构硅碳氮(SiCN)薄膜.SiCN薄膜表面由平均直径约50nm的SiCN纳米颗粒组成,这些纳米颗粒的紧密分布构造了薄膜的致密表面.纳米SiCN薄膜呈现出典型的半导体导电特征.通过调整N2流量参数可以获得不同带隙的SiCN薄膜材料,这种带隙可调的纳米结构SiCN薄膜在未来的半导体光电器件应用领域会有广阔的应用前景.     

石英衬底上溅射制备纳米SiCN薄膜

利用射频溅射方法在石英玻璃上沉积了纳米结构硅碳氮(SiCN)薄膜.SiCN薄膜表面由平均直径约50nm的SiCN纳米颗粒组成,这些纳米颗粒的紧密分布构造了薄膜的致密表面.纳米SiCN薄膜呈现出典型的半导体导电特征.通过调整N2流量参数可以获得不同带隙的SiCN薄膜材料,这种带隙可调的纳米结构SiCN薄膜在未来的半导体光电器件应用领域会有广阔的应用前景.     

石英衬底上溅射制备纳米SiCN薄膜

利用射频溅射方法在石英玻璃上沉积了纳米结构硅碳氮(SiCN)薄膜. SiCN薄膜表面由平均直径约50nm的SiCN纳米颗粒组成，这些纳米颗粒的紧密分布构造了薄膜的致密表面. 纳米SiCN薄膜呈现出典型的半导体导电特征. 通过调整N2流量参数可以获得不同带隙的SiCN薄膜材料，这种带隙可调的纳米结构SiCN薄膜在未来的半导体光电器件应用领域会有广阔的应用前景.     

pH值对制备CZTS颗粒的影响

采用溶剂热法,以CuCl2·2H2O、Zn(Ac)2·2H2O及SnCl4·5H2O作金属源,硫脲(TA)作硫源,PVP作表面活性剂,乙二醇作溶剂,在不同pH值条件下制备了Cu2ZnSnS4(CZTS)颗粒。利用XRD、SEM、EDS和UV-Vis探讨了体系pH值对产物相结构、形貌、粒子数比以及光学性能的影响。结果表明:pH值对CZTS颗粒的相结构、形貌、粒子数比和光学性能均有影响。体系最佳pH值为4,该条件下合成颗粒的结构为锌黄锡矿结构,结晶性较好,颗粒形貌为微米级薄片,粒子数比为1.7:1.1:1.0:4.0,光学带隙为1.51 eV,与太阳能电池所需的最佳带隙接近。     

硒化温度对Cu(In, Al)Se2薄膜结构和光学性质的影响

采用了磁控溅射制备Cu-In-Al金属前驱体薄膜,后硒化快速退火得到铜铟铝硒(Cu(In,Al)Se2,CIAS)薄膜.研究了硒化温度对CIAS薄膜晶体结构和光学性质的影响.研究发现CIAS薄膜的晶体结构依赖于硒化温度,其禁带宽度随硒化温度升高发生红移.研究结果表明,CIAS薄膜的最佳硒化温度为540℃,其晶体结构为纯黄铜矿结构,禁带宽度为.34 eV,对应太阳电池理论最大效率的吸收层材料禁带宽度     

用于纳米劈裂技术的新型芯片及增强拉曼光谱实验

为了定量研究纳米颗粒的间距对拉曼(Raman)光谱强度的影响,研制了具有高稳定性的纳米劈裂芯片及装置。利用此芯片及装置,可以获得纳米金属桥断裂后自动形成的两针状纳米电极(纳米颗粒),并且能在pm级精度上操纵两纳米电极间的距离,以观察相应拉曼光谱强度的变化。在利用两纳米电极作为增强体的基础上引入了第3纳米电极,以观察其位置对拉曼光谱信号的影响。实验结果表明,光谱信号的强度强烈依赖于3纳米电极的相对位置,第3纳米电极的引入能进一步提高增强因子,为拉曼光谱增强机制的理论研究提供了重要参考数据。     

Tuning the Properties of CZTS Films by Controlling the Process Parameters in Cost-Effective Non-vacuum Technique

Highly dispersive Cu₂ZnSnS₄ (CZTS) nanoparticles were successfully synthesized by a simple solvothermal route. A low cost, non-vacuum method was used to deposit CZTS nanoparticle ink on glass substrates by a doctor blade process followed by selenization in a tube furnace to form Cu₂ZnSn (S,Se)₄ (CZTSSe) layers. Different selenization conditions and particle concentrations were considered in order to improve the crystallinity and surface morphology; the annealing temperature was varied between 400°C and 550°C and the annealing time was varied between 5 min and 20 min in a selenium-nitrogen atmosphere. The influence of annealing conditions on structural, compositional, optical and electrical properties of CZTSSe thin films was studied. An improvement in the structural and surface morphology was observed with increasing of annealing temperature (up to 500°C). An enhancement in the crystallinity and surface morphology were observed for thin films annealed for 10–15 min. Absorption study revealed that the band gap energy of as-deposited CZTS thin film was approximately 1.43 eV, while for CZTSSe thin films it ranged from 1.15 eV to 1.34 eV at different annealing temperatures, and from 1.33 eV to 1.38 eV for different annealing times.     

CuSCN Modified Back Contacts for High Performance CZTSSe Solar Cells

Optimization of the back contact interface is crucial for improving the performance of Cu₂ZnSnS₄ (CZTS) thin film solar cells. In this paper, self-depleted CuSCN is deployed as an intermediate layer at the Mo/CZTS interface to improve the quality of the back contact. This CuSCN layer, obtained via aqueous solution processing, reduces the thickness of Mo(S,Se)₂ and eliminates multi-layer crystallization of the absorber by suppressing the undesirable reaction between Mo and Se during the selenization process. By regulating the selenium infiltration into the CZTS precursor films during the selenization process, highly crystalline, single-layer Cu₂ZnSn(S,Se)₄ (CZTSSe) absorber layers are realized. The single-layer CZTSSe absorber exhibits reduced carrier recombination, enhanced carrier density and increased work function. The improved back contact and absorber layer enables 11.1% power-conversion-efficiency to be achieved.     

Enhancement of photo‐conversion efficiency in Cu2ZnSn(S,Se)4 thin‐film solar cells by control of ZnS precursor‐layer thickness

CZTSSe thin‐film absorbers were grown by stacked ZnS/SnS/Cu sputtering with compound targets, and the precursors were annealed in a furnace with a Se atmosphere. We controlled the thickness of the ZnS precursor layer for the CZTSSe thin films in order to reduce the secondary phases and to improve the performance of the devices. The optimal value of the ZnS precursor thickness was determined for the CZTSSe absorbers, and this configuration showed an efficiency of up to 9.1%. In this study, we investigated the depth profiles of the samples in order to determine the presence of secondary phases in the CZTSSe thin films by Raman spectroscopy and Kelvin probe force microscopy. Cu₂SnSe₃, ZnSe, and MoSe₂ secondary phases appeared near the back contact, and the work function distribution of the CZTSSe thin‐film surface and the secondary phase distribution were different depending on the depths of the absorber layer. This phase characterization allows us to describe the effects that changes in the thickness of the ZnS precursor can have on the performance of the CZTSSe thin‐film solar cells. Although it is important to identify the phases, the effects of secondary phases and point defects are not yet fully understood, even in optimal devices. Therefore, phase identification that is based on the work function and the results obtained from the Raman spectra in terms of the depth profile are instrumental to improve the surface and interface of CZTSSe thin‐film solar cells. Copyright © 2015 John Wiley & Sons, Ltd.     

Effects of different precursors on Cu2ZnSnS4 thin film solar cells prepared by sputtering method

In this study, the impacts of different precursors on Cu₂ZnSnS₄ thin film solar cells were investigated. The two kinds of precursors of (Cu+Sn)/Zn and (Cu+Sn)/ZnS were deposited on Mo-coated soda lime glasses by magnetron sputtering. Cu₂ZnSnS₄ (CZTS) films based on different precursors were fabricated by soft annealing and following two-step sulfurization in sulphur vapour. The crystal structure, phase purity, surface morphology, composition and optical properties of CZTS films from different precursors were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), energy dispersive spectrometry (EDS) and UV–vis–NIR spectroscopy, respectively. As a result, the CZTS thin films with smooth surface and uniform compositional ratio distribution were obtained from the precursors of (Cu+Sn)/ZnS. The best conversion efficiency of the fabricated CZTS film solar cell based on (Cu+Sn)/ZnS precursors was 3.36%.     

High‐efficiency Cu2ZnSn(S,Se)4 solar cells fabricated through a low‐cost solution process and a two‐step heat treatment

A method for fabricating high‐efficiency Cu₂ZnSn(S,Se)₄ (CZTSSe) solar cells is presented, and it is based on a non‐explosive, low‐cost, and simple solution process followed by a two‐step heat treatment. 2‐Methoxyethanol was used as a solvent, and Cu, Zn, Sn, chloride salts, and thiourea were used as solutes. A CZTSSe absorber was prepared by sulfurising and then selenising an as‐coated Cu₂ZnSnS₄ (CZTS) film. Sulfurisation in a sulfur vapour filled furnace for a long time (2 h) enhanced the crystallisation of the as‐coated CZTS film and improved the stability of the CZTS precursor, and selenisation promoted further grain growth to yield a void‐free CZTSSe film. Segregation of Cu and S at the grain boundaries, the absence of a fine‐grain bottom layer, and the large grain size of the CZTSSe absorber were the main factors that enhanced the grain‐to‐grain transport of carriers and consequently the short‐circuit current (J_sc ) and efficiency. The efficiency of the CZTS solar cell was 5.0%, which increased to 10.1% after selenisation. For the 10.1% CZTSSe solar cell, the external quantum efficiency was approximately 80%, the open‐circuit voltage was 450 mV, the short‐circuit current was 36.5 mA/cm², and the fill factor was 61.9%. Copyright © 2016 John Wiley & Sons, Ltd.     

Effect of preheating and annealing temperature on the microstructure and optoelectronic properties of CZTS films prepared by sol-gel method

The effects of different preheating and annealing temperatures on the surface morphology, microstructure, and optical properties of Cu2ZnSnS4 (CZTS) thin films are investigated by controlling the preheating and annealing temperatures. The prepared thin films were characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and ultra-violet-visible (UV-Vis) spectroscopy techniques. XRD and Raman spectroscopy showed that a Kesterite structure with a selective orientation along the (112) peak was generated, and the thin films produced at a preheating temperature of 300 °C and annealing temperature of 570 °C had fewer secondary phases, which was beneficial for improving the performance of the solar cells. SEM confirms that the crystallite size increases and then decreases as the temperature increases, and the largest and most uniform crystallite size with the smoothest surface is generated at the above preheating and annealing temperatures. UV-Vis measurements show that the thin films generated at the above temperature have the lowest transmittance and the lowest optical band gap value of 1.46 eV, which is close to the optimal band gap value for solar cells and is suitable as an absorber layer material.     

Optical and Electrical Properties of Cu2ZnSnS4 Film Prepared by Sulfurization Method

Cu₂ZnSnS₄ (CZTS) films were prepared by sulfurization of sputtered Zn/Sn/Cu multilayer thin films. Raman peaks at 251 cm^?1, 289 cm^?1, 336 cm^?1, and 362 cm^?1 were detected, and the optical band gap energy of the CZTS was estimated to be about 1.53 eV. Energy-dispersive spectrometry and x-ray photoelectron spectroscopy reveal that the composition ratio of prepared CZTS film is close to stoichiometric. Photoresponse current measurements show persistent photoconductivity effect, with decay constants τ and β of 5.04 and 0.269, respectively.     

Research on structure of Cu2ZnSn(S, Se)4 thin films with high Sn-related phases

Cu2ZnSn(S, Se)4 (CZTSSe) thin films were deposited on flexible substrates by three evaporation processes at high temperature. The chemical compositions, microstructures and crystal phases of the CZTSSe thin films were respectively characterized by inductively coupled plasma optical emission spectrometer (ICP-OES), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman scattering spectrum. The results show that the single-step evaporation method at high temperature yields CZTSSe thin films with nearly pure phase and high Sn-related phases. The elemental ratios of Cu/(Zn+Sn)=1.00 and Zn/Sn=1.03 are close to the characteristics of stoichiometric CZTSSe. There is the smooth and uniform crystalline at the surface and large grain size at the cross section for the films, and no other phases exist in the film by XRD and Raman shift measurement. The films are no more with the Sn-related phase deficiency.     

铜含量变化对Cu(In,Ga)Se2薄膜微结构的影响

报道了不同的铜含量(Cu/(Ga+In)=0.748~0.982)对Cu(In,Ga)Se2 (CIGS)薄膜微结构的影响.文章中的CIGS薄膜采用磁控溅射金属预置层后硒化的方法制备, 其X射线衍射谱(XRD)中一系列黄铜矿结构CIGS(CH-CIGS)相的衍射峰确认了CH-CIGS相的存在.对CIGS薄膜拉曼光谱的分析表明, 随着铜含量的上升, CIGS薄膜经历了CH-CIGS和有序缺陷化合物(OVC)混合相、CH-CIGS单相、CH-CIGS和CuxSe混合相三种状态.进一步的分析显示, CIGS薄膜拉曼峰的半高宽随铜含量变化, 并在Cu/(Ga+In)=0.9附近时达到最小值, 这说明此时CIGS薄膜具有更好的结晶度和更少的无序性.此外还得到了CIGS薄膜拉曼峰半高宽与铜含量的经验关系公式.这些研究表明拉曼光谱能比XRD更加灵敏地探测CIGS薄膜的微结构, 可望作为一种无损和快速测量方法, 用于对CIGS薄膜晶相和铜含量的初步估计.