硫化亚铜对电极在量子点敏化太阳电池中的应用

报道了一种基于硫族金属复合物N₄H₉Cu₇S₄前驱体溶液制备硫化亚铜对电极的新方法. 分别制备了TiO₂纳米颗粒多孔薄膜和TiO₂纳米棒阵列结构的光阳极, 并在此基础上研究了基于硫化亚铜对电极的CdS/CdSe量子点敏化太阳电池的光电性能, 同时结合电化学阻抗技术考察了硫化亚铜对电极的催化性能. 结果表明: 与铂电极相比, 本方法制备的硫化亚铜电极对多硫电解质具有更高的催化活性, 所组装的CdS/CdSe量子点敏化太阳电池具有更优的光伏性能.     

Fabrication of Ordered TiO2 Porous Thin Films by Sol-Dipping PS Template Method

Monolayer polystyrene spheres (∼400 nm) array templates were assembled orderly on clean glass substrates by dip-drawing method from emulsion of PS and porous TiO₂ thin films were prepared by using sol-dipping template method to fill TiO₂ sol into the interstices among the close-packed PS templates and then annealing to remove the PS templates. The effects of TiO₂ precursor sol concentration and dipping time in sol on the porous structure of the thin films were studied. The results showed pore size of the ordered TiO₂ porous thin film depended mainly on PS size and partly on TiO₂ sol concentration. The shrinkage of pore diameter was about 10% for 0.2 M and 20% for 0.4 M TiO₂ sol concentrations. X-ray diffraction (XRD) spectra indicated the porous thin film was anatase structure. The transmittance spectrum showed that optical transmittance of the porous thin film kept above 70% beyond the wavelength of 430 nm. Optical band-gap of the porous TiO₂ thin film (fired at 550^∘;C) was 3.12 eV.     

CdSe electrodeposition on anodic, barrier or porous Ti oxides. A sensitization effect

A variety of oxide layers, from passive amorphous TiO_x of few nanometer thicknesses to micrometer-thick porous with different anatase to rutile ratios, were prepared by potentiostatic or galvanostatic anodization of Ti metal in H₂SO₄ and HF/H₃PO₄ solutions and used as substrates for electrodeposition of cadmium selenide from acidic selenite baths. The substrate and CdSe microstructures were investigated by X-ray diffraction and electron microscopy techniques. Barrier TiO_x and heterogeneously structured oxide substrates induced growth of zinc blend/wurtzite CdSe, whereas highly ordered porous titanium dioxide (TiO₂) accommodated growth of (10.0) oriented hexagonal CdSe thin layers. Pulsed potential plating was employed to control pore-filling during electrodeposition of CdSe. Photoelectrochemical evaluation of the produced electrodes in polysulfide cell under green light illumination implied a TiO₂ sensitization effect in the case of CdSe/(porous TiO₂)/Ti system, as evidenced by a negative shift in flat band potential and an increase in open circuit potential. The sensitization effect was observed even with CdSe deposited by a single potential pulse signifying the importance of contacting the TiO₂ surface to the electrolytic solution via a very thin layer of CdSe.     

表面修饰的TiO_2太阳能电池界面特性研究

用水热法制备了具有典型锐钛矿晶型的TiO2纳米材料,采用Cr(NO3)3对TiO2薄膜电极进行修饰改性。用X射线衍射(XRD)、扫描电子显微镜(SEM)和光电子能谱(XPS)测试电极的物相及表面结构,结果显示TiO2薄膜表面包覆一层粒径较大的氧化铬颗粒,整个电极仍保持均匀的多孔结构。电流-电压(I-V)曲线测试结果显示,改性后最佳电极的短路电流和光电转换效率分别比改性前提高了31.1%和40.4%。用电化学阻抗谱(EIS)测试电池的界面特性,从测试结果可以看出,相同偏压下,改性后电池的TiO2/染料/电解质界面电阻更大,说明氧化铬包覆层在一定程度上抑制了界面的电子复合,改善了电池的光电输出特性。     

Effect of calcination temperature on the microstructure of porous TiO<Subscript>2</Subscript> film

To obtain porous TiO₂ film, the precursor sol was prepared by hydrolysis of Ti isopropoxide and then complexed with trehalose dihydrate. The porous TiO₂ film was fabricated by the dip-coating technique on glass substrates using this solution. The TiO₂ film was calcined at 500 °C. The maximum thickness of the film from one-run dip-coating was ca. 740 nm. The film was composed of nanosized particle and pores. The porosity of the TiO₂ film was increased by addition of trehalose dihydrate to the sol. The porous TiO₂ films were calcined at different temperatures. The effects of calcination temperature on the microstructure of the porous TiO₂ film were investigated. The porous film prepared from sol containing trehalose still kept the porous structure after calcination at 950 °C. The phase transition temperature of the film from anatase to rutile was shifted from 650 to 700 °C by addition of trehalose to the sol.     

Addition of TiO2 nanowires in different polymorphs for dye-sensitized solar cells

TiO₂ (B) and TiO₂ anatase nanowires were prepared at 150 °C for 120 h by a hydrothermal method followed by calcination in air at 400 °C for 2 h and at 700 °C for 2 h for TiO₂ (B) and TiO₂ anatase, respectively. Although dye-sensitized solar cells (DSC) with fully nanowire electrodes showed a rather low light-to-electricity conversion efficiency of 1.33 % for TiO₂ (B) and 2.42% for TiO₂ anatase, 10 wt % nanowire-dispersed electrodes in a P-25 TiO₂-nanoparticle matrix demonstrated improved efficiency of 6.17 % for TiO₂ (B) and 6.53% for TiO₂ anatase, these exceeding that of pure P-25 electrodes in this work (η=5.59%). The dominant mechanisms of the improvement at 10 wt% for the two different polymorphs are thought to be different, i.e., a light-scattering and film-thickness increment for the TiO₂ (B) system, whereas there is an improved conduction path through the matrix for the TiO₂ anatase system.      

Performance of Au/Ti and Au/TiO2 Nanotube Array Electrodes for Borohydride Oxidation and Oxygen Reduction Reaction in Alkaline Media

Polarization curves and complex kinetics of oxygen reduction (ORR) and borohydride oxidation (BOR) reaction were evaluated at thin Au layer on Ti and TiO₂ electrodes. TiO₂ electrodes prepared included amorphous TiO₂ (AM?TiO₂) and anatase (A?TiO₂). The electrodes structure and nanotube arrays morphology were observed by XRD and SEM, respectively. All electrodes show activity for both ORR and BOR. The use of Au layer over A?TiO₂ produces the strongest synergistic effect for ORR with exchange of 3 electrons. On the other hand, the strongest effect for BOR was observed in case of Au/Ti.     

柔性透明导电基底上二氧化钛自组装薄膜的制备及光电化学性能

通过层层自组装技术, 以结晶的二氧化钛为原料, 在不使用聚电解质的情况下, 免除了高温煅烧, 直接在柔性透明导电基底上制备了全纳米二氧化钛颗粒自组装薄膜。二氧化钛源主要包括带有异种电荷的锐钛矿二氧化钛溶胶和Degussa的P25二氧化钛, 溶胶中的超细二氧化钛纳米晶在制备过程中起到了调节薄膜微观结构的作用, 提高了薄膜的均匀性和致密度。将二氧化钛自组装薄膜作为工作电极, 在三电极体系中进行光电化学测试, 表面均匀致密的二氧化钛薄膜电极表现出了更高的光电化学性能, 加入溶胶后获得的自组装薄膜电极所得到的光电流强度较由全P25组装的薄膜电极提高了近25%。     

二氧化钛纳米晶溶胶内渗透电极对染料敏化太阳能电池的光伏性能的提高

以自制的过氧钛酸(PTA)水溶液为前驱体,用水热法制备了透明锐钛矿相二氧化钛溶胶.无需有机添加剂可得到直径小于7 nm的棒状二氧化钛纳米晶溶胶.通过将溶胶内渗透到染料敏化太阳能电池(DSSCs)的多孔二氧化钛电极后,消除了多孔电极内的大孔并改善了电极内纳米晶之间的连通性.用扫描电子显微镜(SEM)和光学轮廓仪对溶胶内渗透后的光阳极进行了表征.结果表明:小颗粒棒状二氧化钛纳米晶附着在多孔的二氧化钛表面,填充了电极由于烧结产生的大孔,并在多孔的二氧化钛内部形成了有利于电子传输的网络结构.与未经处理的多孔电极相比,改性后的光阳极组装成染料敏化太阳能电池后光电转化效率提高了64%.     

Modification of TiO<Subscript>2</Subscript> electrode films in dye-sensitized solar cells with PMMA

Nanocrystalline porous TiO₂ electrodes for dye-sensitized solar cells (DSC) are modified by adding polymethyl methacrylate (PMMA). The result shows that large holes are formed in the TiO₂ films, and the short circuit photocurrent density and photoelectric conversion efficiency of DSCs are obviously enhanced compared with those without adding the PMMA. The relationship between the photoelectric conversion efficiency and the amount of PMMA is presented. In particular, the highest conversion efficiency was obtained with TiO₂ electrode films of adding 7.5 wt% PMMA, increasing the conversion efficiency by 27.5%.     

表面In掺杂TiO2的N719/TiO2-Inx%/FTO薄膜电极的光电转换效率

采用溶胶-凝胶法制备出In 表面修饰的TiO₂ (TiO₂-Inx%)纳米粒子, x%代表在In 掺杂的TiO₂样品中In³⁺与In³⁺和Ti⁴⁺离子摩尔百分含量. 利用二(四丁基铵)顺式-双(异硫氰基)双(2,2''-联吡啶-4,4''-二羧酸)钌(II)(N719)作为敏化剂, 制备出N719/TiO₂/FTO (氟掺杂锡氧化物)和N719/TiO₂-Inx%/FTO染料敏化薄膜电极. 光电转换效率实验表明, 在薄膜电极+0.5 mol·L^-1 LiI+0.05 mol·L^-1 I₂的三甲氧基丙腈(MPN)溶液+Pt 光电池体系中,N719/TiO₂-Inx%/FTO薄膜电极的光电转换效率均高于N719/TiO₂/FTO, 其中N719/TiO₂-In0.1%/FTO的光电转换效率比N719/TiO₂/FTO提高了20%. 利用X 射线衍射(XRD)、X 射线光电子能谱(XPS)、漫反射吸收光谱(DRS)、荧光(PL)光谱和表面光电流作用谱确定了TiO₂-Inx%样品中In3+离子的存在方式和能带结构; 利用表面光电流作用谱研究了N719/TiO₂-Inx%/FTO薄膜电极的光致界面电荷转移过程. 结果表明, In3+离子在TiO₂表面形成O-In-Cl_n (n=1, 2)物种, 该物种的表面态能级位于导带下0.3 eV处; 在光电流产生过程中, O-In-Cl_n (n=1, 2)表面态能级有效地抑制了光生载流子在TiO₂-Inx%层的复合, 促进了阳极光电流的增加, 从而导致N719/TiO₂-Inx%/FTO薄膜电极的光电转化效率高于N719/TiO₂/FTO, 并进一步讨论了光致界面电荷转移的机理.     

柔性透明导电基底上二氧化钛自组装薄膜的制备及光电化学性能

通过层层自组装技术,以结晶的二氧化钛为原料,在不使用聚电解质的情况下,免除了高温煅烧,直接在柔性透明导电基底上制备了全纳米二氧化钛颗粒自组装薄膜。二氧化钛源主要包括带有异种电荷的锐钛矿二氧化钛溶胶和Degussa的P25二氧化钛,溶胶中的超细二氧化钛纳米晶在制备过程中起到了调节薄膜微观结构的作用,提高了薄膜的均匀性和致密度。将二氧化钛自组装薄膜作为工作电极,在三电极体系中进行光电化学测试,表面均匀致密的二氧化钛薄膜电极表现出了更高的光电化学性能,加入溶胶后获得的自组装薄膜电极所得到的光电流强度较由全P25组装的薄膜电极提高了近25%。     

Highly Active Nickel Nanoparticles Supported on TiO2 Nanotube Electrodes for Methanol Electrooxidation

Nickel nanoparticles/TiO₂ nanotubes/Ti electrodes were prepared by galvanic deposition of nickel nanoparticles on the TiO₂ nanotubes layer on titanium substrates. Titanium oxide nanotubes were fabricated by anodizing titanium foil in a DMSO fluoride‐containing electrolyte. The morphology and surface characteristics of titanium dioxide nanotubes and Ni/TiO₂/Ti electrodes were investigated using scanning electron microscopy and energy‐dispersive X‐ray spectroscopy, respectively. The results indicated that nickel nanoparticles were homogeneously deposited on the surface of TiO₂ nanotubes. The electrocatalytic behaviour of nickel nanoparticles/TiO₂/Ti electrodes for the methanol electrooxidation was studied by electrochemical impedance spectroscopy, cyclic voltammetry, differential pulse voltammetry and chronoamperometry methods. The results showed that Ni/TiO₂/Ti electrodes exhibit a considerably higher electrocatalytic activity toward the oxidation of methanol.     

Porous Si/TiO2 nanowire photoanode for photoelectric catalysis under simulated solar light irradiation

Porous Si/TiO₂ nanowire photoanodes were prepared by a combination of hydrothermal synthesis and metal‐assisted chemical etching. Characterization of samples was conducted using scanning electron microscopy and X‐ray diffraction, the results showing that a porous Si/TiO₂ heterojunction structure was synthesized. Diffuse reflection spectra show that the porous Si/TiO₂ nanowire photoanodes have a strong absorption. Photocurrent measurement shows that the photocurrent of the porous Si/TiO₂ nanowire photoanodes at 6 h is higher than that of others in the measuring region. The photoelectric catalysis (PEC) activities of porous Si/TiO₂ nanowire photoanodes were evaluated in degradation experiments of methylene blue under simulated solar light irradiation, and the sample at 6 h shows the highest PEC activity. Meanwhile, the PEC activity of the porous Si/TiO₂ nanowire photoanode is higher than that of the single direct photocatalysis process or electric catalysis. The mechanism of the PEC of the porous Si/TiO₂ nanowire photoanodes has been explained.     

接枝共聚法制备二氧化钛/聚（苯乙烯-二乙烯基苯）复合微球

本文以KH560、苯乙烯、马来酸酐为连接组分,将二氧化钛接枝到聚（苯乙烯-二乙烯基苯）微球的表面,成功制备了无孔和多孔纳米复合微球。研究了硅烷偶联剂（KH560）和苯乙烯对二氧化钛在无孔微球表面的分散性和接枝数量以及支撑微球的多孔性质对接枝到微球内部的二氧化钛数量的影响。结果表明,KH560和苯乙烯能够提高二氧化钛在微球表面的分散性和稳定性,使二氧化钛以30-80nm的粒径接枝在微球表面。苯乙烯又能使二氧化钛在无孔微球表面的接枝数量从10.4%增大到20.4%。平均孔径为136nm的多孔微球为支撑微球得到的复合粒子中二氧化钛最高接枝量可达26%,明显高于无孔微球和平均孔径为31nm的多孔微球。     

光驱动多孔无定形TiO2的形成机制与光催化性能的研究

以钛酸正丁醇和乙二醇为原料,采用溶剂热法合成了钛乙二醇盐(TG)前躯体,在高压汞灯照射下制备出无定形TiO2。利用X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)、紫外-可见吸收光谱(UV-Vis)、表面光电压谱(SPS)、N2吸附-脱附对所得材料进行了结构和性能的表征。借助X射线吸收精细结构(XAFS)对无定形TiO2的形成机制进行了分析,并通过硝基苯的还原反应考察了材料的光催化性能。结果表明:在紫外光驱动无定形TiO2的形成过程中,中心元素Ti4+的配位环境发生变化,由八面体结构转变为四面体结构;由于特殊的孔道结构使得多孔无定形TiO2显示出较好的光催化活性。     

Fabrication of Au‐Nanoparticle/TiO2‐Nanotubes Electrodes Using Electrochemical Methods and Their Application for Electrocatalytic Oxidation of Hydroquinone

Gold nanoparticle (Au‐NPs)‐Titanium oxide nanotube (TiO₂‐NTs) electrodes are prepared by using galvanic deposition of gold nanoparticles on TiO₂‐NTs electrodes as support. Scanning electron microscopy and energy‐dispersive X‐ray spectroscopy results indicate that nanotubular TiO₂ layers consist of individual tubes of about 60–90 nm diameters and gold nanoparticles are well‐dispersed on the surface of TiO₂‐NTs support. The electrooxidation of hydroquinone of Au‐NPs/TiO₂‐NTs electrodes is investigated by different electrochemical methods. Au‐NPs/TiO₂‐NTs electrode can be used repeatedly and exhibits stable electrocatalytic activity for the hydroquinone oxidation. Also, determination of hydroquinone in skin cream using this electrode was evaluated. Results were found to be satisfactory and no matrix effects are observed during the determination of hydroquinone content of the “skin cream” samples.     

Characteristics of the voltammetric behavior of the hydroxide ion oxidation at disordered mesoporous titanium dioxide electrocatalyst

The alkaline water electrochemical splitting reactions need economical, very energetic, and durable catalysts. Here, a disordered mesoporous and highly defected titanium dioxide (dom-TiO₂) electrocatalyst for the oxidation of hydroxide ion was prepared via ligand-assisted evaporation-induced self-assembly. The (dom-TiO₂) electrocatalyst showed significant electrocatalytic performance for the oxidation of hydroxide ion compared to that of non-porous TiO₂ (bare-TiO₂) and highly-ordered hexagonal mesoporous (hm-TiO₂) electrodes. The chemical and electrochemical parameters of the diffusion (D), concentration in the bulk (C_b), the number of transferred electrons (n), rate constant of heterogeneous electron transfer (k_s), redox potential (E°), and homogeneous chemical rate constant (k_c) for the oxidation of hydroxide ion reaction at the porous TiO₂ electrodes were determined via the convolution–deconvolution voltammetry and competed against that of non-porous (bare-TiO₂) and hm-TiO₂ and catalysts. In addition to the effect of dom-TiO₂ film thickness and the type of supporting electrolytes on the electrochemical parameters of the electrocatalytic oxidation of OH^– ions have been estimated. The convolutive–deconvoluted results show that the dom-TiO₂ electrode catalyst exhibits a superior reaction rate constant among the studied electrodes that depend on the film thickness and type of supporting electrolyte.     

Highly efficient dye-sensitized SnO2 solar cells having sufficient electron diffusion length

Dye-sensitized solar cells (DSCs) were fabricated from mesoporous SnO₂ electrodes, which were prepared from nano-sized SnO₂ particles. Current–voltage characteristics of the DSCs were compared with DSCs prepared from conventional TiO₂ electrodes, which have similar amount of adsorbed dye with the SnO₂. As a result, short-circuit current of the SnO₂DSC were comparable with that of the TiO₂DSCs, and more than 15 mA/cm² was obtained with the SnO₂ at the thickness of 10 μm under one sun conditions. Electron diffusion coefficients and lifetimes in the SnO₂ and TiO₂ electrodes were measured, showing slower diffusion and longer lifetime in the SnO₂DSC than in the TiO₂. The results imply that the electron transport and transfer dynamics in such electrodes is dominated by the influence of intra-band charge traps, and the control of the trap conditions would be the key strategy to employ various metal oxides for such solar cells.     

Facile Preparation and Lithium Storage Properties of TiO2@Graphene Composite Electrodes with Low Carbon Content

Over the past decade, TiO₂/graphene composites as electrodes for lithium ion batteries have attracted a great deal of attention for reasons of safety and environmental friendliness. However, most of the TiO₂/graphene electrodes have large graphene content (9–40 %), which is bound to increase the cost of the battery. Logically, reducing the amount of graphene is a necessary part to achieve a green battery. The synthesis of TiO₂ nanosheets under solvothermal conditions without additives is now demonstrated. Through mechanical mixing TiO₂ nanosheets with different amount of reduced graphene (rGO), a series of TiO₂@graphene composites was prepared with low graphene content (rGO content 1, 2, 3, and 5 wt %). When these composites were evaluated as anodes for lithium ion batteries, it was found that TiO₂+3 wt % rGO manifested excellent cycling stability and a high specific capacity (243.7 mAh g^?1 at 1 C; 1 C=167.5 mA g^?1), and demonstrated superior high‐rate discharge/charge capability at 20 C.