Metal/metal sulfide functionalized single-walled carbon nanotubes: FTO-free counter electrodes for dye sensitized solar cells

The use of single-walled carbon nanotubes (CNT) thin films to replace conventional fluorine-doped tin oxide (FTO) and both FTO and platinum (Pt) as the counter electrode in dye sensitized solar cells (DSSC) requires surface modification due to high sheet resistance and charge transfer resistance. In this paper, we report a simple, solution-based method of preparing FTO-free counter electrodes based on metal (Pt) or metal sulfide (Co(8.4)S(8), Ni(3)S(2)) nanoparticles/CNT composite films to improve device performance. Based on electrochemical studies, the relative catalytic activity of the composite films was Pt > Co(8.4)S(8) > Ni(3)S(2). We achieved a maximum efficiency of 3.76% for the device with an FTO-free counter electrode (Pt/CNT). The device with an FTO- and Pt-free (CoS/CNT) counter electrode gives 3.13% efficiency.     

CoSe/TiN同轴纳米管阵列在染料敏化太阳能电池对电极中的应用研究

以钛网作为基底,采用阳极氧化、氨气氮化的方法制备了TiN纳米管,随后电沉积CoSe,制备了CoSe/TiN/Ti同轴纳米管阵列电极。循环伏安结果表明,CoSe/TiN/Ti电极对I-3具有高的电催化还原性能,这归因于高催化活性的CoSe和高导电的TiN的协同效应。以CoSe/TiN/Ti电极作为对电极组装染料敏化太阳能电池,电池的能量转换效率高达9.25%,比传统Pt/FTO对电极组装的电池(8.09%)高1%。这一结果为非Pt对电极纳米结构的设计提供了一个很好的思路。     

花状硫化铜的合成及其光电催化性能

通过硫化介孔Cu_2O微球得到花状Cu_xS纳米催化材料,并采用丝网印刷法制备出Cu_xS/FTO对电极。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等表征手段对所得材料的结构和形貌进行了探究,同时系统考察了溶液浓度、硫化时间、催化剂印刷层数对Cu_xS/FTO电极的催化性能影响和所组装量子点敏化太阳电池的光电转换效率,其中基于Zn-Cu-In-Se量子点敏化的电池转换效率达8.80%,表现出花状Cu_xS优异的光电催化性能。     

Patterned 3-dimensional metal grid electrodes as alternative electron collectors in dye-sensitized solar cells

We describe the application of 3-dimensional metal grid electrodes (3D-MGEs) as electron collectors in dye-sensitized solar cells (DSCs) as a replacement for fluorinated tin oxide (FTO) electrodes. Requirements, structure, advantages, and limitations of the metal grid electrodes are discussed. Solar conversion efficiencies of 6.2% have been achieved in 3D-MGE based solar cells, comparable to that fabricated on FTO (7.1%). The charge transport properties and collection efficiencies in these novel solar cells have been studied using electrochemical impedance spectroscopy.     

碳纳米管负载Ni2P作为染料敏化太阳能电池对电极的性能研究

本文以碳纳米管(CNTs)与Ni2P纳米晶制备CNTs-Ni2P复合材料,首次研究其染料敏化太阳能电池(DSSCs)的光阴极材料性能.使用X射线衍射(XRD)和透射电子显微镜(TEM)测定材料结构,观察材料形貌.结果表明,复合材料由碳纳米管和六方结构的磷化镍构成,无其它磷化物杂相,磷化镍纳米晶(约10 nm)分散于CNTs表面.交流阻抗(EIS)测试显示,与CNTs和Ni2P对电极相比,CNTs-Ni2P对电极的电荷转移电阻和扩散阻抗较低,接近Pt-FTO对电极水平.CNTs-Ni2P对电极的DSSCs光电流达12.9 mA·cm-2,能量转化效率达5.6%,接近Pt-FTO对电极的DSSCs能量转化效率(5.9%).这归因于高电催化活性的磷化镍纳米晶与高电导CNTs的协同效应.     

Screen-printed copper ion-selective electrodes

A simple, low-cost and reproducible method for the mass production of potentiometric ion-selective electrodes for copper ions is presented. These planar, strip sensors were obtained by screen-printing. The application of pastes cured at low temperature allows printing of the sensors on low-cost, plastic substrates. The pastes for printing of ion-sensitive thick-film membranes were based on copper (1) and copper (II) sulfides. The analytical characteristics of the thick-film electrodes were compared. The analytical properties (range of determination, sensitivity, selectivity, response time) of the copper (I) sulfide-based sensors were comparable with those for conventional ion-selective electrodes.     

Inverse opal carbons for counter electrode of dye-sensitized solar cells

We investigated the fabrication of inverse opal carbon counter electrodes using a colloidal templating method for DSSCs. Specifically, bare inverse opal carbon, mesopore-incoporated inverse opal carbon, and graphitized inverse opal carbon were synthesized and stably dispersed in ethanol solution for spray coating on a FTO substrate. The thickness of the electrode was controlled by the number of coatings, and the average relative thickness was evaluated by measuring the transmittance spectrum. The effect of the counter electrode thickness on the photovoltaic performance of the DSSCs was investigated and analyzed by interfacial charge transfer resistance (R(CT)) under EIS measurement. The effect of the surface area and conductivity of the inverse opal was also investigated by considering the increase in surface area due to the mesopore in the inverse opal carbon and conductivity by graphitization of the carbon matrix. The results showed that the FF and thereby the efficiency of DSSCs were increased as the electrode thickness increased. Consequently, the larger FF and thereby the greater efficiency of the DSSCs were achieved for mIOC and gIOC compared to IOC, which was attributed to the lower R(CT). Finally, compared to a conventional Pt counter electrode, the inverse opal-based carbon showed a comparable efficiency upon application to DSSCs.     

An Interconnected Ternary MIn2S4 (M=Fe,Co, Ni) Thiospinel Nanosheet Array: A Type of Efficient Platinum‐Free Counter Electrode for Dye‐Sensitized Solar Cells

The ternary iron‐group thiospinels of metal diindium sulfides (MIn₂S₄, M=Fe, Co, Ni) with a vertically aligned nanosheet array structure are fabricated through an in situ solvothermal method on F‐doped tin oxide (FTO) substrates, which are employed as one type of platinum (Pt)‐free counter electrodes (CEs) in structure‐dependent dye‐sensitized solar cells (DSSCs). A DSSC assembled with ternary CoIn₂S₄ CE achieves an photoelectric conversion efficiency (PCE) of 8.83 %, outperforming than that of FeIn₂S₄ (7.18 %) and NiIn₂S₄ (8.27 %) CEs under full sunlight illumination (100 mW cm⁻², AM 1.5 G), which is also comparable with that of the Pt CE (8.19 %). Putting aside that the interconnected nanosheet array provides fast electron transfer and electrolyte diffusion channels, the highest PCE of CoIn₂S₄ based DSSC results from its largest specific surface area (144.07 m² g⁻¹), providing abundant active sites and the largest electron injection efficiency from CE to electrolyte.     

An Interconnected Ternary MIn2S4 (M=Fe,Co, Ni) Thiospinel Nanosheet Array: A Type of Efficient Platinum-Free Counter Electrode for Dye-Sensitized Solar Cells

The ternary iron-group thiospinels of metal diindium sulfides (MIn₂S₄, M=Fe, Co, Ni) with a vertically aligned nanosheet array structure are fabricated through an in situ solvothermal method on F-doped tin oxide (FTO) substrates, which are employed as one type of platinum (Pt)-free counter electrodes (CEs) in structure-dependent dye-sensitized solar cells (DSSCs). A DSSC assembled with ternary CoIn₂S₄ CE achieves an photoelectric conversion efficiency (PCE) of 8.83 %, outperforming than that of FeIn₂S₄ (7.18 %) and NiIn₂S₄ (8.27 %) CEs under full sunlight illumination (100 mW cm⁻², AM 1.5 G), which is also comparable with that of the Pt CE (8.19 %). Putting aside that the interconnected nanosheet array provides fast electron transfer and electrolyte diffusion channels, the highest PCE of CoIn₂S₄ based DSSC results from its largest specific surface area (144.07 m² g⁻¹), providing abundant active sites and the largest electron injection efficiency from CE to electrolyte.     

Captopril Electrochemical Oxidation on Fluorine‐Doped SnO2 Electrodes and Their Determination in Pharmaceutical Preparations

A novel application of fluorine‐doped tin oxide (FTO) electrodes is reported in the present work. To this end, the captopril electrochemical oxidation mechanism on FTO electrodes at various pH and its determination in pharmaceutical preparations was investigated. Captopril oxidation on FTO proceeds at pH between 2.0 and 4.0. The study revealed that interferences for captopril determination in pharmaceutical samples was totally suppressed using these electrode materials. Voltammetric survey showed an anodic peak at about 0.375 V (Ag|AgCl) for captopril oxidation, that takes place through an EC process at pH interval 2.0–4.0. The investigation demonstrated that captopril oxidation occurs through protonated species and these electroactive species interact by adsorption on FTO electrodes, with a large heterogeneous rate constant and a mechanism involving 1H⁺/1e^? in the global reaction. Moreover, a captopril sensor based upon FTO electrodes, with a linear range miliMolar, is proposed. These electrodes are promising candidates for the efficient electrochemical determination of captopril in pharmaceutical preparations.     

Screen-printed copper ion-selective electrodes

A simple, low-cost and reproducible method for the mass production of potentiometric ion-selective electrodes for copper ions is presented. These planar, strip sensors were obtained by screen-printing. The application of pastes cured at low temperature allows printing of the sensors on low-cost, plastic substrates. The pastes for printing of ion-sensitive thick-film membranes were based on copper (I) and copper (II) sulfides. The analytical characteristics of the thick-film electrodes were compared. The analytical properties (range of determination, sensitivity, selectivity, response time) of the copper (I) sulfide-based sensors were comparable with those for conventional ion-selective electrodes. Received: 12 January 2000 / Revised: 13 March 2000 / Accepted: 16 March 2000     

电沉积-置换法制备Pt/Ti对电极及其对染料敏化太阳能电池性能的提升

采用电沉积-置换法在Ti片上制备了染料敏化太阳能电池(DSSC)的对电极Pt/Ti. 形貌表征结果显示, 与传统热解法制备的Pt/FTO对电极相比, Pt/Ti对电极Ti基底上Pt催化颗粒的粒径和分散性得到显著改善. 光电流-光电压特性曲线测试结果表明, 以Pt/Ti为对电极的DSSC与以Pt/FTO为对电极的DSSC相比, 光电转化效率提高了20.8%. 由于Pt颗粒分散性和粒径的改善所引起的Pt催化性能的提高、 Pt/Ti对电极更低的电阻以及Ti基底更好的反光性能是提升DSSC性能的原因.     

High‐Performance Platinum‐Free Dye‐Sensitized Solar Cells with Molybdenum Disulfide Films as Counter Electrodes

By using a radio‐frequency sputtering method, we synthesized large‐area, uniform, and transparent molybdenum disulfide film electrodes (1, 3, 5, and 7 min) on transparent and conducting fluorine‐doped tin oxide (FTO), as ecofriendly, cost‐effective counter electrodes (CE) for dye‐sensitized solar cells (DSSCs). These CEs were used in place of the routinely used expensive platinum CEs for the catalytic reduction of a triiodide electrolyte. The structure and morphology of the MoS₂ was analyzed by using Raman spectroscopy, X‐ray diffraction, and X‐ray photoemission spectroscopy measurements and the DSSC characteristics were investigated. An unbroken film of MoS₂ was identified on the FTO crystallites from field‐emission scanning electron microscopy. Cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel curve measurements reveal the promise of MoS₂ as a CE with a low charge‐transfer resistance, high electrocatalytic activity, and fast reaction kinetics for the reduction of triiodide to iodide. Finally, an optimized transparent MoS₂ CE, obtained after 5 min synthesis time, showed a high power‐conversion efficiency of 6.0 %, which comparable to the performance obtained with a Pt CE (6.6 %) when used in TiO₂‐based DSCCs, thus signifying the importance of sputtering time on DSSC performance.     

Metal chalcogenide complex-mediated fabrication of Cu2S film as counter electrode in quantum dot sensitized solar cells

Cu2S film onto FTO glass substrate was obtained to function as counter electrode for polysulfide redox reactions in CdS/CdSe co-sensitized solar cells by sintering after spraying a metal chalcogenide complex, N4H9Cu7S4 solution. Relative to Pt counter electrode, the Cu2S counter electrode provides greater electrocatalytic activity and lower charge transfer resistance. The prepared Cu2S counter electrode represented nanoflower-like porous film which was composed of Cu2S nanosheets on FTO and had a higher surface area and lower sheet resistance than that of sulfided brass Cu2S counter electrode. An energy conversion efficiency of 3.62% was achieved using the metal chalcogenide complex-mediated fabricated Cu2S counter electrode for CdS/CdSe co-sensitized solar cells under 1 sun, AM 1.5 illumination.     

三种CuS对电极的制备及其对量子点敏化太阳能电池光电性能的影响

近几年,量子点敏化太阳能电池因其具有低成本、易合成、高的光电转换效率等优点而广受关注. 半导体金属硫化物具有良好的物理和化学性质,被广泛应用于各个领域,其中,铜硫化物凭借其优异的电化学催化活性,而成为量子点敏化太阳能电池良好的对电极材料. 本文通过3种不同的方法在FTO表面生长CuS纳米阵列（依次记为CuS-1、CuS-2、CuS-3）,并对样品进行晶相表征、表面形貌分析、电化学性能测试以及相应量子点敏化太阳能电池器件组装,最终发现CuS-3样品具有最优的光电性能.     

Nitrogen‐Doped Carbon Nanotube‐Based Bilayer Thin Film as Transparent Counter Electrode for Dye‐Sensitized Solar Cells (DSSCs)

Carbon nanotubes (CNTs) have been widely considered as one of the promising candidates for replacing fluorine‐doped tin oxide (FTO)/platinum (Pt) electrodes to reduce the fabrication cost of dye‐sensitized solar cells (DSSCs). Here, we report that a bilayer transparent film containing N‐doped CNTs (which are highly catalytic) and normal CNTs (which are highly conductive) as a counter electrode in DSSCs results in efficiencies up to 2.18 %, yet still maintains a good transparency with a transmittance of approximately 57 % at 550 nm.     

溅射-置换法制备染料敏化太阳能电池对电极Pt/FTO

采用溅射-置换(SD)法在导电玻璃(FTO)基底上制备了染料敏化太阳能电池(DSSC)对电极SD-Pt/FTO.形貌表征显示,和热解法(PY)所获得的对电极(PY-Pt/FTO)相比,SD法获得的对电极SD-Pt/FTO上Pt颗粒分散性显著改善.光电流-光电压特性曲线测试表明,以SD-Pt/FTO为DSSC对电极的光电转化效率比以PY-Pt/FTO为DSSC对电极的提高了16.5%.DSSC电池性能改善与SD-Pt/FTO对电极具有较低的电阻和由Pt颗粒分散性改善引起催化性能改善密切相关.     

Influence of fluoride-doped tin oxide interlayer on Ni–Sb–SnO2/Ti electrodes

In the present work, fluoride-doped tin oxide (FTO) as an interlayer was introduced into nickel and antimony co-doped tin dioxide coated titanium electrodes to investigate the influence of FTO interlayer on the structural properties and lifetime performance of the electrodes. Scanning electron microscopy and X-ray diffraction techniques were used to characterize the morphology and crystal structure of the electrodes with or without FTO interlayer. The electrode surface became smoother with FTO interlayer introduced while the crystallite size reduced. Electrochemical impedance spectroscopy was also adopted to analyze the electrodes’ electrochemical behavior. With FTO interlayer introduced, the formation of titanium dioxide-insulating layer on the titanium substrate was significantly retarded during the anodic process. The accelerated lifetime tests presented that the lifetime of the electrodes with proper FTO interlayer was six times longer than that without FTO interlayer. The mechanisms for the electrodes’ lifetime enhancement with FTO interlayer were discussed.     

铜锌锡硫的合成及其光电应用

铜锌锡硫(CZTS)半导体常作为对电极材料被应用于量子点敏化太阳能电池(QDSCs)中,然而效率一直低于4%。本文采用热注入法合成出纳米尺寸的CZTS并制成对电极(CZTS/FTO),用其组装的CdSe QDSCs和CdSeTe QDSCs的效率(PCE)分别达到了5.75%和7.64%。电化学阻抗谱、塔菲尔极化等表征证明电池效率的提高与CZTS良好的导电性及催化活性联系密切。     

简易合成Cu2SnSe3作染料敏化太阳能电池对电极

采用简易溶剂热法合成直径为150-250 nm的Cu2SnSe3纳米颗粒.以Cu2SnSe3"墨水"为前驱体采用滴落涂布法在掺氟二氧化锡基板上沉积Cu2SnSe3薄膜作为染料敏化太阳能电池(DSSC)对电极.利用场发射扫描电镜(FESEM)、透射电镜(TEM)、X射线衍射(XRD)、拉曼光谱(Raman)、能谱仪(EDS)等对Cu2SnSe3纳米颗粒的形貌、结构和组成进行表征.结果表明:产物纯净无杂项且符合化学计量比.以Cu2SnSe3为对电极的DSSC转化效率为7.75%,与铂对电极DSSC效率相当(7.21%).研究表明,DSSC的光电流密度和影响因子与Cu2SnSe3薄膜厚度密切相关,这是由于不同厚度的Cu2SnSe3薄膜作对电极所对应的催化位置数目和电阻值不同.电化学阻抗谱研究说明,Cu2SnSe3因具有类似铂良好的电催化性能而适合用作染料敏化太阳能电池对电极材料.本文以Cu2SnSe3代替贵金属铂,提供了一种廉价制备高效染料敏化太阳能电池对电极的新方法.