硅酸钠在太阳能电池单晶硅表面织构化的作用

在单晶硅太阳电池的制备过程中,通常利用晶体硅[100]和[111]不同晶向在碱溶液中各向异性腐蚀特性,在表面形成类似于“金字塔”的绒面结构,使得入射光在硅片表面多次反射,提高入射光吸收效率,可提高单晶硅太阳电池的转换效率。实验探索了一种廉价的硅织构化腐蚀技术,即单独采用Na2SiO3代替传统的氢氧化钠和异丙醇溶液,以减少价格较高的异丙醇的用量,降低成本。不采用异丙醇或其他机械消泡的条件下,用质量分数为5％的Na2SiO3溶液在80℃腐蚀120min,单晶硅片表面可获得最佳反射率为12．56％的减反射绒面。虽然与传统的氢氧化钠和异丙醇溶液效果相比,单独使用Na2SiO3溶液腐蚀单晶硅片表面的反射率和均匀性略差,但在传统的氢氧化钠和异丙醇体系中加入质量分数为0．1％的Na2SiO3也会促进腐蚀反应的进行,获得更加均匀的减反射绒面。     

单晶硅太阳电池表面绒面制备及其性质研究

单晶硅太阳能电池的表面织构化所形成的陷光效应,可以增强对光的吸收,提高电池的转化效率。本文研究了制绒液主要成分含量、制绒温度以及时间对绒面织构形成的影响。采用扫描电镜分析了试样的表面形貌,分光光度法研究了试样的反射率。通过分析确定了单晶硅太阳电池表面织构化的最佳工艺参数为1.5%wt的NaOH、1.5%wt的Na2SiO3.9H2O和6.5%vol的IPA,反应温度为80℃,反应时间为25min,在此工艺参数下所制得的硅片样品绒面平均反射率为9.85%。     

TiO_2-SiO_2-GeO_2凝胶玻璃涂膜的制备及其光学性能研究

以四氯化锗、正硅酸乙酯、钛酸丁酯为原料 ,采用溶胶 -凝胶法制备了TiO2 -SiO2 -GeO2涂膜。利用DTA、TG、XRD研究了TiO2 -SiO2 -GeO2 凝胶向玻璃的转化。利用XPS研究了TiO2 -SiO2 GeO2 体系中Ti、Si、Ge与O原子间的成键情况。测试了涂膜的红外反射率并依据k k关系计算出了折射率。结果表明涂膜中形成了Ti O Si ,Ge O Si和Ti O Ge键结构 ,该涂膜在 9～ 11μm波长范围存在红外反射窗口 ,在CO2 激光波长附近折射率小于 1,存在反常色散现象 ,适合作空芯波导材料     

Si掺杂TiO2光催化材料的制备、活性及其机理

采用两步溶胶-凝胶法制备了Si掺杂TiO2(Si:TiO2)粉体,通过X射线衍射、热重-差热分析和X射线光电子能谱表征了Si:TiO2粉体样品的晶相及表面结构,以甲基橙为目标物考察了Si掺杂TiO2的光催化活性.研究发现:Si:TiO2粉体在水中降解有机物时,比纯TiO2粉体具有更高的光催化活性;Si:TiO2粉体具有...     

Ti—Al合金在混合溶液体系中微弧氧化

利用自制的混合溶液体系采用正交优化的方法,研究了Ti-Al合金表面微弧氧化层的制备工艺与性能.结果表明:自制的混合溶液体系可在Ti-Al合金表面制备出性能良好的陶瓷层;陶瓷层的主要相是Al2TiO5和Al6Si2O13;陶瓷层的耐蚀性较Ti-Al合金基体的有很大的提高.     

TiO2-SiO2薄膜的光催化活性和超亲水性能

采用溶胶凝胶法在普通玻璃表面制备了均匀的TiO2-SiO2光催化薄膜,并研究了SiO2含量对TiO2光催化性能和超亲水性能的影响。对罗丹明B的光降解实验表明,加入少量的SiO2可提高TiO2薄膜的光催化性能,过多的SiO2降低了TiO2光催化活性,但超新水性的实验则表明,较多的SiO2加入量提高了玻璃表面的超亲水性能。     

Ti/Si复合纳米微粒光催化降解NO-2

采用溶胶-凝胶法制备出不同质量比的Ti/Si复合纳米粉末,并利用XRD、BET、XPS、UVvis等技术研究了Ti/Si复合微粒的表面结构形态变化,以及对污染物NO-2光催化降解的影响.研究表明,Ti/Si复合微粒的光催化活性明显高于TiO2微粒,并且m(Ti)m(Si)=21时催化降解NO-2最佳.TiO2微粒以锐钛矿相高度分散在SiO2网络中,粒径约为10nm,并与SiO2形成Si-O-Ti桥氧结构,提高了TiO2微晶的热稳定性,比表面积和表面缺陷.UV-Vis吸收光谱显示复合微粒的光谱吸收发生蓝移,有利于吸附降解污染物NO-2,所合成的Ti/Si复合纳米微粒是一种具有实用价值的新型光催化剂.     

活性二氧化钛膜光催化性能研究与应用

综述比较了制备TiO2 薄膜的几种方法 ,研究了活性TiO2 膜的光催化原理 ,光诱导亲水性原理 ,除污防雾性能以及采用溶胶 凝胶法制备的TiO2 膜对两种含氯苯酚的降解效果。分析了活性TiO2 膜作为一种功能材料目前在国内外工业应用状况。     

玻璃表面静电自组装TiO2基薄膜研究

采用静电自组装薄膜技术在玻璃基片表面上制备了TiO2基薄膜。研究TiO2基薄膜的光催化活性和超亲水性。     

Ti／Si复合纳米微粒光催化降解NO2^—

采用溶胶－凝胶法制备出不同质量比的Ti/Si复合纳米,并利用XRD、BET、XPS、UVvis等技术研究了Ti/Si复合微粒的表面结构形态变化,以及对污染物NO2^-光催化降解的影响,研究表明,Ti/Si复合微粒的光催化活性明显高于TiO2微粒,并且m(Ti):m(Si)＝2：1时催化降解NO2^-最佳。TiO2微粒以脱钛矿相高度分散在SiO2网络中,粒径约为10nm,并与SiO2形成Si-O-Ti桥氧结构,提高了TiO2微晶的热稳定性,比表面积和表面缺陷。UV－Vis吸收光谱显示复合微粒的光谱吸收发生蓝移,有利于吸附降解污染物NO2^-,所合成的Ti/Si复合纳米微粒是一种具有实用价值的新型光催化剂。     

Nanostructure control of graphene-composited TiO2 by a one-step solvothermal approach for high performance dye-sensitized solar cells

We present a one-step solvothermal approach to prepare uniform graphene-TiO(2) nanocomposites with delicately controlled TiO(2) nanostructures, including ultra-small 2 nm nanoparticles, 12 nm nanoparticles and nanorods. Using three composites as photoanode materials, the effect of nanostructure of graphene-composited TiO(2) on the performance of dye-sensitized solar cells was investigated, and results showed that the ultra-small 2 nm TiO(2)-graphene composite based photoanode exhibited the highest power conversion efficiency of 7.25%.     

Use of Etching to Improve Efficiency of the Multicrystalline Silicon Solar Cell by Using an Acidic Solution

Surface texturing methods using an alkaline solution for monocrystalline Si (c-Si) solar cells have been widely accepted to improve cell performance. However, multicrystalline Si (mc-Si) cells are difficult to be texturized by alkaline etching, because the grains in the substrates are randomly oriented. In this study, we considered a HF/HNO ₃/H ₂O acid solution for texturing the mc-Si cells. The conversion efficiency of mc-Si solar cells textured with the solution (HF/HNO ₃/H ₂O = 30:1:2.5) has relatively high values. In our study, sufficient light confinement is achieved, which contributes to the improvement of both the short circuit current and the conversion efficiency of the acid textured cells. The optimal acid etching ratio HF:HNO ₃:H ₂O = 30:1:2.5 with etching time of 60 s and lowering 41.9 % of the R value can improve 111.8 % of the conversion efficiency (η) of the developed solar cell. More detailed information is used to measure the internal quantum efficiency (IQE) and the lifetime of minority carriers. Thus, the acid texturing approach is instrumental to achieve high efficiency in mass production using relatively low-cost mc-Si as the starting material with proper optimization of the fabrication steps.     

Periodic nano/micro-hole array silicon solar cell

In this study, we applied a metal catalyst etching method to fabricate a nano/microhole array on a Si substrate for application in solar cells. In addition, the surface of an undesigned area was etched because of the attachment of metal nanoparticles that is dissociated in a solution. The nano/microhole array exhibited low specular reflectance (<1%) without antireflection coating because of its rough surface. The solar spectrum related total reflection was approximately 9%. A fabricated solar cell with a 40-μm hole spacing exhibited an efficiency of 9.02%. Comparing to the solar cell made by polished Si, the external quantum efficiency for solar cell with 30 s etching time was increased by 16.7%.     

Densely aligned rutile TiO(2) nanorod arrays with high surface area for efficient dye-sensitized solar cells

One-dimensional (1-D) TiO(2) nanorod arrays (NRAs) with large inner surface area are desired in dye-sensitized solar cells (DSSCs). So far, good performance of DSSCs based on 1-D rutile TiO(2) NRAs remains a challenge mainly owing to their low dye-loading ability resulting from the insufficient specific surface area of 1-D TiO(2) nanostructures. In this paper, densely aligned TiO(2) NRAs with tunable thickness were grown directly on transparent conductive fluorine-doped tin oxide (FTO) substrates by hydrothermal method, followed by a facile chemical etching route to further increase the specific surface area of the TiO(2) NRAs. The etching treatment leads to the split of TiO(2) nanorods into secondary nanorods with a reduced diameter, which markedly enlarges the inner surface area of the TiO(2) NRAs. The formation of 1-D rutile TiO(2) nanotube arrays (NTAs) is observed as well in the etched TiO(2) films. Finally, a DSSC efficiency of 5.94% was achieved by utilizing an etched TiO(2) NRA as the photoanode, which is so far the best DSSC efficiency that has been reported for the 1-D rutile TiO(2) NRA films.     

Design Analysis of Heterojunction Solar Cells with Aligned AZO Nanorods Embedded in p-type Si wafer

Higher price-per-watt of silicon (Si) solar cells is still the main bottleneck in their widespread use for power generation due to their expensive manufacturing process. The n-type zinc oxide (n-ZnO) and p-type Si (p-Si) based single heterojunction solar cell is one of the several methods being tried to replace conventional Si single homojunction solar cell technology. In this work, we have explored the possibility of producing photovoltaic materials by employing RF sputtering and hydrothermal technologies. Conductivity of ZnO nanorods has been increased by aluminium (Al) doping. The advantages of using Al doped ZnO (AZO) nanorods (NRs) have been investigated. The integrated reflectance (IR) has been found to be only ~2.86%. Hence, the short circuit current density (Jsc) has been increased by minimizing the reflection loss of solar cells. AZO NR array have been developed over several large area (3″ × 3″) textured p-Si wafers to confirm the repeatability. The maximum efficiency of AZO NRs/Si solar cell of 0.8 cm2 area has been found to be 6.25% for textured p-type Si wafer which is much higher than reported hitherto for this type of solar cell. A simple, low temperature, low cost procedure is thus being proposed, which has the potential of attaining lower cost of production of heterojunction silicon solar cells.     

Fabrication and characterization of silicon wire solar cells having ZnO nanorod antireflection coating on Al-doped ZnO seed layer

In this study, we have fabricated and characterized the silicon [Si] wire solar cells with conformal ZnO nanorod antireflection coating [ARC] grown on a Al-doped ZnO [AZO] seed layer. Vertically aligned Si wire arrays were fabricated by electrochemical etching and, the p-n junction was prepared by spin-on dopant diffusion method. Hydrothermal growth of the ZnO nanorods was followed by AZO film deposition on high aspect ratio Si microwire arrays by atomic layer deposition [ALD]. The introduction of an ALD-deposited AZO film on Si wire arrays not only helps to create the ZnO nanorod arrays, but also has a strong impact on the reduction of surface recombination. The reflectance spectra show that ZnO nanorods were used as an efficient ARC to enhance light absorption by multiple scattering. Also, from the current-voltage results, we found that the combination of the AZO film and ZnO nanorods on Si wire solar cells leads to an increased power conversion efficiency by more than 27% compared to the cells without it.     

Nanopatterning of silicon with use of self-organized porous alumina and colloidal crystals as mask

Nanopatterning processes based on a localized anodization of Si and the subsequent chemical etching of SiO₂ were developed to fabricate a dot array and a hole array on an Si surface using self-organized anodic porous alumina as a mask. Through the porous alumina mask, regularly arranged metal nanopatterns on the Si surface were fabricated by the electroless deposition of Cu nanodots in a CuSO₄/hydrofluoric acid (HF) solution. The periodicity of the Cu dot arrays was determined using the pore interval of the upper anodic alumina. Using self-assembled nanospheres as a mask for an electroless plating of metals such as Cu and Ag on the Si substrate, the patterning of an ordered honeycomb structure and a hexagonally arranged convex array of metals on Si was also developed by the combination of colloidal crystal patterning and wet chemical etching. The proposed patterning processes of the Si surface have potential technological applications in fields that need textured surfaces of controlled nanoscale periodicity and morphology owing to their relative simplicity and low cost.     

Silicon Solar Cell with Nanoporous Structure Formed on a Textured Surface

A nanoporous silicon (Si) surface was formed on monocrystalline silicon solar cells by electrochemical etching. The galvanostatic mode was applied to conventional n–p–p⁺ solar cells, which were fabricated by pyramidal texturing, phosphorous diffusion, screen-printing, rapid thermal firing, and laser isolation (effective area of 144.7 cm²). Without an additional antireflection layer such as SiN _x , the anodic reaction of the Si wafer could provide uniform porous layers on a pyramidal surface (111) with relatively low reflectance, and it would improve the photovoltaic performance.     

Tribological performance of UV picosecond laser multi-scale composite textures for C/SiC mechanical seals: Theoretical analysis and experimental verification

The performance of mechanical seals can be improved by using multi-scale composite textures with spiral grooves and micro-dimples, but without a clear texture function mechanism, it is difficult to optimize the textures on the sealing surface. This research established a mathematical model based on the mass-conservative JFO cavitation boundary to analyze the mechanical seal performance of multi-scale composite micro-textures. We use the multi-grid method for numerical solutions, investigate the hydrodynamic lubrication characteristics of composite-textured mechanical seals, and inspect the coupling effect of micro-dimples and spiral grooves. We also analyzed the influence of the geometrical parameters of composite textures on the sealing performance and optimized the sealing surface textures using theoretical analysis. The numerical analysis showed that the multi-scale composite-textured mechanical seal produced a coupling effect between the micro-dimples and spiral grooves, which improved the lubrication of the sealing pair. Eventually, C/SiC mechanical seal bench tests confirmed the tribological improvement of composite textures compared with the un-textured seal under various sealing liquid pressures and rotation speeds. Through comparing the Stribeck curve, the multi-scale composite textured C/SiC mechanical seals have a lower and more stable friction torque than the un-textured.     

染料敏化太阳电池介孔薄膜电极的研究进展

介绍了染料敏化太阳电池多孔二氧化钛薄膜电极的结构、工作原理及其制备方法,并进一步阐述了减小电荷复合速率、改进薄膜电极性能、提高器件的光电转化效率的方法,主要涉及多孔二氧化钛薄膜电极的复合、掺杂和表面包覆等表面改性处理技术。指出了基于有序二氧化钛薄膜电极、柔性二氧化钛薄膜电极的染料敏化太阳电池和叠层薄膜结构的太阳电池高效的转化效率和应用方便的特点,并在此基础上展望了未来的研究方向。