两步法电化学制备CuInSe2太阳能电池吸收层材料

采用先沉积In2Se3薄膜,再沉积CuInSe2的两步法电化学制备薄膜太阳能电池CuInSe2吸收层材料.通过XRD、SEM、EDX等分析手段检测了材料形貌、结构以及组分等,结果表明薄膜组分比为CuIn1.7Se2.2,其中In和Se的含量相对化学计量比有所增加.循环伏安法研究表明CuInSe的沉积属于诱导共沉积范畴.     

低In电解液电沉积制备CuInSe2吸收层

通过线性电位扫描分析了低In电解液中的阴极电化学反应,结果表明柠檬酸钠可以降低Cu2+的活性,而H2SeO3的加入可导致阴极上Se元素与Cu+和In3+发生复杂的协同反应.低In电解液中恒电位沉积的薄膜与CIS的化学计量比相差较大,分段电位的恒电位沉积得到的薄膜更接近于CuInSe2(CIS)化学计量比.薄膜在N2气氛上退火处理,得到了黄铜矿结构CIS薄膜,禁带宽度为1.06eV.     

电沉积制备CIS太阳能电池吸收层材料

在Cu衬底上用电沉积的方法沉积金属In,再通过硒蒸气硒化处理成功制备了CuInSe2薄膜.用X射线衍射(XRD)、扫描电镜(SEM)、X射线能谱(EDS)对制备的薄膜进行相组成、微观结构、表面形貌等分析,研究了制备工艺条件对薄膜性能的影响.结果表明:电沉积的In在低温热处理阶段与衬底Cu扩散形成Cu-In合金预制层,预制层在硒化阶段生成CuInSe2,合金中过量Cu生成CuSe表面层,未反应的In转变为Cu16In9,形成Cu衬底/Cu16In9/ CuInse2/CuSe结构.     

硒化温度对CuInSe2薄膜性能的影响

采用中频交流磁控溅射方法沉积Cu-In薄膜,并采用固态源硒化方法制备CuInSe2(CIS)薄膜,考察了硒化温度对CIS薄膜性能的影响.采用SEM和EDS观察和分析了它们的表面形貌和成分,采用XRD表征了薄膜的组织结构,采用霍尔测试仪测量了薄膜的载流子浓度和霍尔迁移率.结果表明,Cu-In薄膜由In和Cu11In9两相组成,在不同的硒化温度下制备的CIS薄膜,均具有单一的黄铜矿CuInSe2相结构.随着硒化温度的升高,CIS薄膜的晶粒直径增大,当硒化温度达到550℃时,晶粒直径已接近于2 μm.硒化温度继续升高,晶粒之间出现孔洞和缝隙等缺陷.530℃的硒化温度下制得的弱p型CIS薄膜,最符合CuInSe2的化学计量比,最适于制备太阳能电池吸收层.     

分段恒电位电化学沉积法制备CuInSe2吸收层

采用分段恒电位电沉积法在FTO导电玻璃上制备了CuInSe2 (CIS)薄膜.通过线性电位扫描分析了阴极的电化学反应,并通过电化学沉积法制备了CIS薄膜.结果表明,恒电位电化学沉积的薄膜与CIS的化学计量比相差较大,增加溶液中铟离子的浓度,可以提高铟在镀层的含量,使薄膜更接近CIS化学计量比.而采用分段恒电位法沉积薄膜,可以抑制铜硒化合物的生长,使薄膜更接近于CIS化学计量比.     

Cu/In原子比及硫化温度对于CuInS2薄膜性能影响

采用中频交流磁控溅射方法,在玻璃基底上沉积Cu-In预制膜,采用固态硫化法制备获得了CuInS2(CIS)吸收层薄膜.考察了预制膜Cu/In原子比及硫化温度对于CIS薄膜结构及禁带宽度影响.通过XRD及Raman光谱分析了薄膜结构,通过近红外透过曲线得出薄膜禁带宽度.结果表明,随着预制膜中Cu与In原子比(Cu/In)及硫化温度不断升高,薄膜CuAu(CA)相含量逐渐降低,黄铜矿(CH)相逐渐升高,薄膜结晶性逐渐改善.600℃以上硫化时薄膜中主要存在CH相CuInS2.薄膜禁带宽度随着预制膜中Cu/In原子比及硫化温度不断升高而升高,Cu/In原子比为1.05,硫化温度为500℃时薄膜禁带宽度可达1.40eV.     

Bi2Te3热电薄膜的电化学原子层外延制备

采用电化学原子层外延法(ECALE)在Au电极上成功地制备了Bi2Te3化合物热电薄膜.通过循环伏安扫描研究Te和Bi在Au衬底上的电化学特性,使用自动沉积系统交替欠电位沉积Te、Bi原子层200个循环获得沉积物.XRD、EDX和FESEM测试结果表明循环沉积200层后得到的沉积物Bi和Te的化学计量比为2:3,且是Bi2Te3薄膜化合物,而非单质Bi和Te的简单混合;薄膜均匀、致密、平整且可重复性好,以(015)为最优取向外延生长的.     

镁镍功能薄膜的制备及电致变色性能的研究

采用恒电位法在铜基片上沉积出镁一镍薄膜,采用循环伏安法研究了N-N二甲基甲酰胺溶液中Mg2 、Ni2 的电化学行为,并通过反射法对薄膜的电致变色性能进行了表征.电致变色前后,镀层薄膜的颜色及在可见光范围内的透光和反射光的能力表现出很大的差别,显示出良好的电致变色性能,而且此过程具有较好的重复性.     

铜/镍纳米多层膜脉冲电沉积法制备及沉积机理初探

利用脉冲电沉积法成功制备出了层状结构清晰的Cu/Ni纳米多层膜.采用线性扫描伏安法、循环伏安法以及铜镍沉积过程中的电压-电流曲线等方法,研究了在硼酸系溶液中铜/镍纳米多层膜的沉积机理,使用扫描电子显微技术观察了多层膜的微观结构.结果表明:铜的沉积为扩散控制步骤,镍的沉积分为2步进行,即中间经历Ni(OH)+的过渡状态;铜、镍的沉积电位分别为-0.5 V和-1.1 V.经计算和测量对比,本脉冲法制备的多层膜符合基础电沉积原理.     

MnSe/Ti薄膜电沉积制备及其表征

在钛电极表面上,采用电化学方法在0.1mol/L MnSO4和0.002mol/L SeO2的溶液中沉积硒化锰(MnSe)薄膜。循环伏安实验结果表明在-1.60～-1.70V电位范围易发生Mn和Se共沉积。然后采用XRD、SEM及EDS等研究沉积电位分别在-1.55、-1.60、-1.65和-1.70V时得到薄膜的特性,结果表明上述选定的电位不影响沉积层立方结构优先沿(200)晶面向;不同电位对沉积层形貌及化学计量数有显著影响。控制电位可以沉积得到不同特征的MnSe薄膜。     

Preparation of CuInSe2 thin films by selenization of co-sputtered Cu-In precursors using rapid thermal processing

CuInSe₂ thin films have been synthesized by selenization of co-sputtered Cu-In precursors using rapid thermal processing (RTP). Heat treatments from 400 to 450 °C for periods between 1 min and 10 min were carried out on (Cu-In)/Se precursors. Phase evolution as function of reaction temperature and holding time was analyzed according to XRD and SEM results. Severe Se loss during RTP was proved in our experiments and has been reported by many other researchers. To solve the problem, a new effective way of reducing Se loss was presented, which is based on low temperature heat treatment at 250 °C before high temperature annealing. Nearly single-phase CuInSe₂ thin films have been achieved by annealing precursors at 250 °C for 5 min then 450 °C for 1 min. Se loss can be significantly reduced via low temperature heat treatment by the fact that under 250 °C, Se is evaporated mildly and largely consumed as Cu-Se and In-Se binary selenides.     

Formation of CuInSe2 by the selenization of sputtered Cu/In layers

Single layers of Cu and In were deposited onto Mo coated glass substrates by radio frequency sputtering. The Cu11In9 phase has been found to be the majority phase in these precursors. The selenization of the sputtered layers has been achieved by depositing a 1 μm Se layer onto the precursor by thermal evaporation followed by an annealing in vacuum. Samples were annealed at different temperatures varying between 100–600°C at intervals of 50°C. The chalcopyrite structured ternary phase of CuInSe2 with a significant amount of preferential orientation in the (112) direction was obtained in samples annealed at 400°C or above. Morphological, compositional and structural analyses of the samples annealed at different temperatures were performed using a variety of complementary techniques. The results were analysed to explain the growth of CuInSe2 on the selenization of sputtered Cu-In precursors. The occurrence of various binary phases of Cu-In, Cu-Se and In-Se in different annealing temperature ranges has also been investigated. The phenomenon of volume expansion in CuInSe2 on selenization has been found to manifest itself as a shift in the characteristic (110) X-ray diffraction peak of Mo. This revised version was published online in November 2006 with corrections to the Cover Date.     

Electrodeposition of chalcopyrite films from ionic liquid electrolytes

An air and water stable room-temperature ionic liquid based on choline chloride/urea eutectic mixture has been investigated as a system for the electrodeposition of CuInSe₂ (CIS) and Cu(In,Ga)Se₂ (CIGS) films for photovoltaic applications. Deposition potentials and bath compositions were optimized to obtain Cu-In, Cu-In-Se and Cu-In-Ga-Se precursor films, which were selenized in a tube furnace at 500 °C for 30 min to form CIS and CI(G)S films. Photo-electrochemical measurements on these selenized films showed p-type photoconductivity with band gaps of 1.0 eV and 1.09 eV, respectively, for CIS and CIGS. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photocurrent spectroscopy and electrolyte electro-reflectance spectroscopy (EER).     

Structural analysis of CuInSe2 thin films prepared by selenization of Cu-In films

This study involves the characterization of thin films of copper indium diselenide (CuInSe₂) deposited on soda-lime glass substrates using a two-step process. In this technique electron-beam-evaporated Cu-In precursor layers were reacted with an atmosphere containing H₂Se gas. The morphological and structural aspects of the CuInSe₂ layers were studied (by scanning electron microscopy and X-ray diffraction) as a function of the Cu-In film morphology and the selenization temperature profile and exposure time. It was found that the Cu-In precursor morphology has a significant influence on the structural properties of the final CuInSe₂ film. Selenization of the Cu-In alloys (irrespective of the structure considered) directly at high temperature resulted in films with poor structural properties. However, a vast improvement in the adhesion properties and morphology of the CuInSe₂ films were observed when the Cu-In films were exposed to a reactive selenium atmosphere while ramping the temperature between 150 C and 400 C. Selenization of triple-layer structures (Cu/In/Cu and In/Cu/In) resulted in films with good structural properties and excellent compositional uniformity.     

Formation of CuInSe2 absorber layers formed using co-electrodeposition combined with selenization

Stoichiometric CuInSe2 absorber layers were formed using co-electrodeposition coupled with selenization. We investigated the influence of the metal ion ratio, supporting electrolyte, and deposition voltages on the structural and chemical properties of Cu-In alloys. The increases in deposition voltage and metal ion concentration helped to form In-rich Cu-In alloy with dendrite structure composed of a long central trunk with secondary branches. In addition, on increasing the concentration of the supporting electrolyte, the ratio of In to Cu in the Cu-In alloy increased, and surface morphology improved. Finally, based on an optimized co-electrodeposition process, the selenization of Cu-In alloys using the evaporation of the Se element was employed to form high quality CuInSe2 absorber layers.     

Instantaneous preparation of CuInSe2 films from elemental In, Cu, Se particles precursor films in a non-vacuum process

CuInSe₂ (CIS) films are successfully prepared by means of non-vacuum, instantaneous, direct synthesis from elemental In, Cu, Se particles precursor films without prior synthesis of CIS nanoparticle precursors and without selenization with H₂Se or Se vapor. Our precursor films were prepared on metal substrates by spraying the solvent with added elemental In, Cu, and Se particles. Precursor films were instantaneously sintered using a spot welding machine. When the electric power was fixed to 0.6 kVA, elemental In, Cu, or Se peaks were not observed and only peaks of CIS are observed by X-ray diffraction (XRD) on the film sintered for 7/8 s. We can observe XRD peaks indicative of the chalcopyrite-type structure, such as (101), (103) and (211) diffraction peaks. We conclude that the synthesized CIS crystals have chalcopyrite-type structure with high crystallinity.     

Low-temperature direct conversion of Cu-In films to CuInSe₂ via selenization reaction in supercritical fluid

In this study, we achieve the direct conversion of metallic Cu-In films to compound semiconductor CuInSe(2) films, at quite low temperature around 300 °C using less hazardous metalorganic selenium source in supercritical fluid (SCF). We investigated the effects of temperature and fluid (ethanol) density, and found that supercritical ethanol plays a crucial role in this low-temperature selenization reaction. Such SCF-assisted direct conversion reactions can facilitate large-scale, low-temperature, and rapid synthesis of CuInSe(2) films, which can potentially lead to the low-cost production of solar cells.     

Solution synthesis and characterization of n-type zinc indium selenide films for the buffer layer used in Cu(In,Ga)Se2 solar cells

Zinc indium selenide (ZnIn₂Se₄) films were successfully prepared via a spin coating process followed by a selenization treatment. The single-phased ZnIn₂Se₄ derived from spin coated precursors was synthesized on selenization at 450 °C for 0.5 h. The crystal structure was confirmed to be a defective chalcopyrite structure. Optical absorption spectra revealed that the value of a band gap of ZnIn₂Se₄ was equal to 1.83 eV. Via the spin coating route with a sequential selenization process, films with a densified microstructure were obtained. Additionally, raising the selenization temperatures significantly increased the crystallinity and n-type conductivity of the prepared films. Conversion efficiency of the Cu(In,Ga)Se₂ solar device using the spin-coated ZnIn₂Se₄ films reached 3.52 %. Moreover, the series resistance and shunt conductance of the fabricated solar cells were decreased, owing to an improved p-n quality and reduced defects of the prepared ZnIn₂Se₄ layers. Results of this study demonstrate that the spin coating process was is an effective approach to prepare the n-type ZnIn₂Se₄ layers used in Cu(In,Ga)Se₂ solar cells.     

CuInSe2 thin films formed by selenization of Cu–In precursors

CuInSe2 (CIS) thin films were grown by selenization of electro-deposited or electroless-deposited Cu–In precursors. Cu–In precursors were formed by layer-by-layer electro-deposition of Cu and In as well as by electroless co-deposition of Cu and In. The major phases in the precursors were found to be Cu11In9 and elemental In. It was found that the stoichiometric CIS phase (CuInSe2) may be formed by selenization of the precursors at temperatures higher than 500°C. The Cu–In precursors as well as CIS films were characterized by X-ray diffraction and scanning electron microscopy. The cubic CIS phase was formed when electroless-deposited Cu–In precursor was selenized, whereas the chalcopyrite CIS or the In-rich phase (CuIn2Se3.5) was formed when the layered precursors were selenized at a high temperature.     

Composition and Morphology of Electrodeposited CuInSe_2 Precursor Films

CuInSe2 (CIS) precursor films have been prepared by electrodeposition in aqueous solution. The electrodeposited films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) for structural, morphological and componential properties. The influence of deposition potential and Na-citrate concentration on composition and morphology of electrodeposited films was studied in detail. It is found that the film morphology is strongly influenced by deposition potential and Na-citrate concentration. Films with large and homogenous grain size and ratio of Cu/In approaching 1 were obtained at deposition potentials of -0.7 and -0.75 V vs the saturated calomel electrode (SCE) and Na-citrate concentration of 500 mmol/L. Chalcopyrite phase CuInSe2 is contained in precursor films that have poor crystallinity.