TiO2颗粒尺寸对染料敏化太阳电池内电子输运特性影响研究

采用强度调制光电流谱(IMPS)和强度调制光电压谱(IMVS)研究了染料敏化太阳电池(DSC)内部电子传输和背反应动力学特性.在纳米TiO₂薄膜厚度相同的情况下,借助于IMPS/IMVS测量了由3种不同TiO₂颗粒尺寸大小薄膜制备出DSC的电荷传输特征参数值.IMPS/IMVS理论模型拟合实验测量数据的结果表明：在不同入射光强下,随着颗粒尺寸的增大,电子扩散系数(D_n)增大,而电子寿命(τ_n 关键词： 染料敏化 太阳电池 IMPS/IMVS 电子传输     

染料敏化太阳电池中TiO2颗粒界面接触对电子输运影响的研究

采用溶胶-凝胶法制备TiO₂浆料,通过丝网印刷技术印刷和不同温度曲线烧结TiO₂薄膜,并应用于染料敏化太阳电池(DSC).高分辨透射电子显微镜发现,低温下多孔薄膜中TiO₂颗粒之间呈现点接触,510 ℃烧结后TiO₂颗粒间由点接触变为面接触,近邻颗粒数增多,接触面积增大.同时采用强度调制光电流谱(IMPS)和强度调制光电压谱(IMVS)技术,研究了不同颗粒接触方式和接触面积对电子传输与复合的影响.结果表明:在420- 510 ℃之间,随着烧结温度提高,颗粒接触面积增大,电子传输时间(τ _d)缩短,电子有效扩散长度(L _n)增大,暗电流减小;当烧结温度达到550 ℃时,薄膜比表面积减小,多孔结构坍塌,表面态密度增大,电子传输时间(τ _d)增大.电池光伏特性研究表明:在480-510 ℃范围内烧结得到的TiO₂薄膜,电池短路电流密度(J_sc)最佳,电池效率(η)最好. 关键词： 界面接触 电子输运 暗电流 染料敏化太阳电池     

染料敏化太阳能电池二氧化锡光阳极表面原子层沉积氧化铝研究

染料敏化薄膜太阳能电池作为一种新型的太阳能电池吸引了世界范围内的研究。采用二氧化锡代替传统的二氧化钛作为染料敏化太阳能电池的光阳极,使用含有I-/I-3氧化还原电解对的液态电解质。同时,通过原子层沉积(ALD)法,在150℃下使用三甲基铝(TMA)和水作为前驱体和氧化剂沉积氧化铝。并研究了ALD超薄氧化铝包覆二氧化锡颗粒对染料敏化太阳能电池光电转换效率的影响。椭圆偏振仪(SE)分析结果表明ALD每周期沉积速率约为1.2。X射线衍射(XRD)和场发射扫描电镜(FESEM)的结果表明,超薄氧化铝包覆没有影响多孔二氧化锡纳米晶薄膜的晶体结构和表面形貌。紫外-可见光谱(UV-Vis)研究发现随着氧化铝的沉积周期数增加,染料敏化电池光阳极吸附染料的能力增加。最后,对ALD氧化铝对染料敏化太阳能电池性能的影响机理进行了探讨。     

混合植物染料敏化的太阳能电池性能

采用植物染料叶绿素和叶黄素,模拟光合作用的光电转化,以单独和混合等方式敏化纳晶多孔TiO2膜电极,制备了太阳能光化学电池.测试电池的输出特性发现,叶绿素和叶黄素以不同浓度混合后敏化的电池转化效率η为叶绿素和叶黄素单独敏化时的5.8倍和1.4倍,最大输出功率Wopt为叶绿素和叶黄素单独敏化时的5.7倍和1.4倍.混合染料敏化表现出明显的非线性叠加效应,其效能超过两种染料分别敏化时的线性叠加.混合染料的协同效应对提高电池转化效率,获取高效、廉价、环保能源具有重要意义.     

锐钛矿相TiO2纳米管的制备及其染料敏化太阳电池

以商用金红石相TiO₂粉末为原料,通过在碱性溶液中150℃水热48h的方法合成TiO₂纳米管.采用SEM,TEM,XRD分析手段对TiO₂纳米管的形貌和结构演变进行了表征.制成的TiO₂纳米管与TritonX-100,乙酰丙酮混合后,通过丝网印刷的方法涂敷到ITO导电玻璃衬底上,并且在450℃下烧结30min后得到可应用于染料敏化太阳电池的多孔光阳极.将此光阳极浸泡于N719染料敏化后,与镀铂对电极组装电池,两者之间灌 关键词： 2纳米管')" href="#">TiO₂纳米管 染料敏化太阳电池 水热法     

金属氧化物修饰对介孔纳米TiO2电极的染料敏化太阳能电池电化学性能的影响

将介孔TiO₂纳米粒子(m-TiO₂)多孔膜电极浸入相应的金属硝酸盐的500 oC热处理修饰金属氧化物(如Mg、ZnO、Al₂O₃或NiO).结果表明,金属氧化物修饰均可形成能垒对m-TiO₂膜电极的界面电荷传输过程产生影响,但外加偏压下其膜内电子传输和界面电荷复合均明显依赖于修饰氧化物的种类及其存在形态. 金属氧化物修饰的膜电极在电子传输和界面复合方面的变化与DSSCs的电流-电压特性曲线的变化规律具有明显的相关性,可不同程度地提高电池的光电压,而MgO、ZnO和NiO修饰的电池效率分别提高了23%、13%和6%. 上述结果表明调控电池的本征参数可以改善TiO₂-基DSSCs的性能.     

纳米TiO2多孔膜的微结构对染料敏化纳米薄膜太阳电池性能的影响

采用溶胶-凝胶方法，在不同的实验条件下获得平均粒径从15到25nm左右的纳米TiO２2颗粒.利用这些颗粒制备出的纳米多孔薄膜，应用于染料敏化纳米薄膜太阳电池. 通过x射线 衍射仪分析，得到TiO２₂颗粒的晶相以及晶粒度大小，用透射电子显微镜观察 了纳米TiO２₂颗粒的形貌和尺寸.应用于太阳电池的纳米TiO２₂多 孔膜，经基于布朗诺尔-埃米特-泰 勒（BET）的多层吸附理论的比表面积测试和孔径分布测试，获得了多孔膜的微 关键词： 溶胶-凝胶法 2')" href="#">纳米TiO２₂ 染料敏化 太阳电池     

纳米TiO2叶片状阵列电极的制备及其在染料敏化太阳电池中电子的输运性能

在低温条件下采用定向刻蚀技术, 对金属Ti片表面用H₂O₂溶液进行刻蚀氧化, 制备了垂直生长的纳米TiO₂叶片状阵列薄膜电极. 通过X射线衍射分析表明, 纳米TiO₂叶片状阵列薄膜经500 ℃下烧结1 h后, 从无定型转变为锐钛矿相. 场发射扫描电子显微镜观察表明: 在80 ℃下的H₂O₂溶液刻蚀氧化, 经1 d制备得到的是Ti片表面垂直生长的叶片状阵列, 其形貌均匀且完整地 关键词： 2')" href="#">纳米TiO₂ 叶片状阵列电极 染料敏化太阳电池 电子传输     

TiCl4处理多孔薄膜对染料敏化太阳电池中电子传输特性影响研究

借助于强度调制光电流谱(IMPS)和强度调制光电压谱(IMVS)技术,研究了纳米TiO₂多孔薄膜在TiCl₄溶液处理后组装成的染料敏化太阳电池(DSC)中电子传输和背反应动力学特性. 研究表明:纳米TiO₂多孔薄膜经TiCl₄溶液处理后,电池中暗电流减小,电子寿命τ_n明显延长,电子传输时间τ_d缩短,电子有效扩散系数D_n增大,电子扩散长度L_n值升高,入射单色光子/电子转化效率η_IPCE增加,光生电荷量Q_oc显著增加. 文章从微观层面上研究了TiCl₄溶液处理纳米TiO₂多孔薄膜对DSC内部电子的产生、传输和复合过程的影响,从而很好地解释了电池光伏性能随TiCl₄溶液处理的变化关系. 关键词： 4')" href="#">TiCl₄ 电子传输 染料敏化 太阳电池     

染料敏化太阳电池中TiO2膜内电子传输和背反应特性研究

采用强度调制光电流谱(IMPS)和强度调制光电压谱(IMVS)研究电池内部电子传输机理和电子背反应动力学特性.利用理论表达式对不同TiO₂多孔膜厚度(d)的电池实验数据进行了拟合,得到了电池的吸收系数(α)、电子扩散系数(D_n)、电子寿命(τ_n)、电子传输时间(τ_d)和入射单色光光电转化效率(IPCE)等微观参数的数值.研究表明：膜薄有利于加快电子传 关键词： 染料敏化 太阳电池 IMPS/IMVS 传输     

Effect of dispersing media on microstructure of electrophoretically deposited TiO2 nanoparticles in dye-sensitized solar cells

In the present study, dye-sensitized solar cells were fabricated using electrophoretically deposited layers of titanium dioxide nanoparticles from two common organic media, acetone and isopropanol. Characterization of the obtained layers by scanning electron microscope and atomic force microscope showed that a non-uniform porous layer was obtained in acetone; however, deposition from the titanium dioxide/isopropanol cell resulted in the formation of a relatively uniform microstructure. Ultraviolet-visible (UV-vis) spectra of adsorbed dye on the two layers show that more dye is loaded on the layer deposited in acetone. Current-voltage characteristics of the cells indicate that for the case of the cells made by the layer formed in acetone, the internal resistance of the cell is more than that of isopropanol medium which would decrease the efficiency of the cell. This difference was attributed to the reduction of effective surface area and also the loss of particles interconnection as a result of the presence of aggregates within the layer obtained in acetone.     

电解质中添加氧化物颗粒对染料敏化太阳电池性能的增强

"在液态电解质中加入纳米TiO2、微米TiO2、Al2O3和ZrO2颗粒后,在一定的氧化物含量下,都不同程度地提高了DSC的光电特性,而以加入12.5%的纳米TiO2 (P25)得到最高的提高,达到5.5%,比没有加入氧化物颗粒的DSC效率提高达到51%以上．利用电化学阻抗谱和循环伏安法研究了在染料敏化太阳电池液态电解质中加入各种氧化物颗粒对电池电解质特性的影响,结果发现,加入氧化物颗粒后,由于界面效应,提供了I3-的快速扩散通道,从而I3-扩散系数得到较大提高,电解质/Pt电极间的电荷传输电阻下降,改善     

TiO2 Wedgy Nanotubes Array Flims for Photovoltaic Enhancement

In this study, TiO₂ wedgy nanotubes with rectangular cross-sections were fabricated on transparent conductive substrates by using TiO₂ nanorods as the precursor via the anisotropic etching route. TiO2 nanotubes with V-shaped hollow structure and the special crystal plane exposed on the tube wall possess nature of high surface area for more dye molecules absorption, and the strong light scattering effects and dual-channel for effective electron transport of the TiO₂ V-shaped nanotubes based dye-sensitized solar cell exhibit a remarkable photovoltaic enhancement compared with the TiO₂ nanorods. The photoanode based on our V-shaped TiO₂ nanotubes with a length of 1.5 μm show a 123% increase of the dye loading and a 182% improvement in the overall conversion efficiency when compared with 4 μm rutile TiO₂ nanorods photoanode.     

Molecule-solid interaction: Electronic states of anthracene-9-carboxylic acid adsorbed on the surface of TiO2

Electronic excited states of athracene-9-carboxylic acid chemisorbed on the surface of TiO₂ nanoparticles were investigated by means of the electroabsorption (Stark effect) spectroscopy at low temperature. In addition to a fraction of molecules adsorbed with no significant spectral changes, two forms absorbing at lowered energy (25,600 cm⁻¹ and 24,900 cm⁻¹) were observed, that exhibit a large increase in the excited-minus-ground state dipole moments, 2.7 D and 9.5 D, respectively, as well as changed molecular polarizabilities. The dipole moments are interpreted as indicators of partial charge-transfer character of the excited state, corresponding to the optical electron transfer from the adsorbate onto TiO₂ concomitantly with the photon absorption. Consequences of these observations are shortly discussed in the context of the electron transfer process in dye-sensitized solar cells.     

Effect of surface roughness of TiO2 films on short-circuit current density of photoelectrochemical cell of ITO/TiO2/PVC-LiClO4/graphite

This paper reports the effect of surface topography of titanium dioxide films on short-circuit current density of photoelectrochemical solar cell of ITO/TiO₂/PVC-LiCLO₄/graphite. The films were deposited onto ITO-covered glass substrate by screen-printing technique. The films were tempered at 300 °C, 350 °C, 400 °C, 450 °C and 500 °C for 30 min to burn out the organic parts and to achieve the films with porous structure. The surface roughness of the films were studied using scanning electron microscope (SEM). Current–voltage relationship of the devices were characterized in dark at room temperature and under illumination of 100 mW cm⁻² light from tungsten halogen lamp at 50 °C. The device utilising the TiO₂ film annealed at 400 °C produces the highest short-circuit current density and open-circuit voltage as it posses the smoothest surface topography with the electrolyte. The short-circuit current density and open-circuit voltage of the devices increase with the decreasing grain size of the TiO₂ films. The short-circuit current density and open-circuit voltage are 0.6 μA/cm² and 109 mV respectively.     

TiO_2/Eu~(3+)下转换薄膜的制备及其在染料敏化太阳能电池中的应用

采用溶胶-凝胶法制备了TiO2/Eu3+下转换薄膜,并对其光学特性和光电性能进行了分析。将其应用到染料敏化太阳能电池(DSSC)中,利用其下转换特性将部分紫外光转换为能被染料吸收利用的可见光,提高了DSSC的光照强度,促进了短路电流的增大。荧光光谱显示,下转换薄膜在受到394 nm紫外光照射时可发射出550~640 nm的可见光,具有下转换功能特性。下转换薄膜可以增加电池对太阳光的吸收范围,当涂有二层下转换薄膜时,短路电流密度从8.05 mA·cm-2提高到9.62 mA·cm-2,光电转换效率从3.67%提高到4.32%,转换效率相对提高了17.7%。     

TiO_2/Sm~(3+)下转换薄膜的制备及其在染料敏化太阳能电池中的应用

采用溶胶-凝胶法制备了TiO2/Sm3+下转换薄膜,利用其下转换特性将紫外光转换为可见光,提高了可见光光照强度。利用X射线衍射和荧光光谱对TiO2/Sm3+粉体进行了表征,并对TiO2/Sm3+下转换薄膜进行了荧光光谱测试和紫外-可见分光光度计测试。荧光光谱显示,TiO2/Sm3+薄膜在受到395 nm紫外光照射时可发射出540~600 nm连续波长的可见光,具有下转换特性。二层TiO2/Sm3+下转换薄膜的可见光透过率与单纯的TiO2薄膜基本相同,利用其下转换特性使电池短路电流提高了13.2%,光电转换率提高了16.2%。     

Surface evolution of rutile TiO2 (1 0 0) in an oxidizing environment

Transmission electron microscopy (TEM) has been used to study the rutile TiO₂ (1 0 0) surface in an oxidizing environment. By changing annealing conditions, TiO₂ surfaces with different morphologies are obtained. We report a new centered (2 × 2) surface reconstruction on this surface. Our experimental data indicates that this is a meta-stable, oxygen deficient structure formed as the disordered surface regains its stoichiometry in an oxidizing annealing environment.     

Synthesis and properties of magnetic and luminescent Fe3O4/SiO2/Dye/SiO2 nanoparticles

A simple and reproducible method was developed to synthesize a novel class of Fe₃O₄/SiO₂/dye/SiO₂ composite nanoparticles. As promising candidates for use in bioassays, the obtained nanoparticles have an average diameter of 30 nm, and the thickness of the outer shell of silica could be tuned by changing the concentration of the silicon precursor tetraethyl orthosilicate during the synthesis. These multifunctional nanoparticles were found to be highly luminescent, photostable and superparamagnetic. The luminescence intensity of the nanoparticles was increased as the dye concentration was increased in the preparation process. The color of the luminescence was successfully tuned by incorporating different dyes into the nanoparticles. The measurements of the emission spectra indicated that relative to the dye molecules dissolved in ethanol, the emission of the dye-doped nanoparticles exhibited either a red shift or a blue shift, to which a tentative explanation was given.