三维多孔复合碳层对电极的制备及其光伏性能研究

基于TiO_2光阳极、Pt对电极的染料敏化太阳能电池(DSSC)因其优异的光电转换特性受到了广泛的关注,然而Pt昂贵的价格制约了其发展与应用.针对这一问题,本文设计、制备了一种由相对致密且高导电的石墨膜(PC层,底层)及多孔碳纳米颗粒膜(CC层,顶层)构成的低成本、高性能三维多孔复合碳层对电极.基于该CC/PC对电极的DSSC具有优异的光伏性能:在1.5标准太阳光照射下,其填充因子高达65.28%(较Pt对电极高4.1%)、光电转换效率高达5.9%(为Pt对电极的94.2%). CC/PC对电极的优异光伏性能主要归因于其独特的三维多孔导电结构,该结构有极高的比表面积和丰富的催化反应活性位,有利于电子的快速传输及离子的快速转移,在这些因素的协同作用下,其光电转换性能大大改善.     

Graphene/carbon nanotubes composites as a counter electrode for dye-sensitized solar cells

As an alternative platinum counter electrode in dye-sensitized solar cells (DSSCs), carbon materials based counter electrode were prepared using multi-walled carbon nanotubes (MWNTs)/graphene nano-sheets (GNS) composite by simple doctor blade method. We found that the photovoltaic performance was strongly influenced by the concentration of GNS in composite electrode. The composite electrode with 60% MWNTs and 40% GNS based DSSCs showed the maximum power conversion efficiency of 4.0% while sputter deposited platinum counter electrode based DSSCs showed a power conversion efficiency of 5.0%.     

Application of Pt sputter-deposited counter electrodes based on micro-patterned ITO glass to quasi-solid state dye-sensitized solar cells

The effects of the Pt catalyst sputter deposited on the patterned ITO glass (SD-Pt/pITO) on the photovoltaic properties and charge-transfer characteristics at the Pt/electrolyte interface of dye-sensitized solar cells (DSSCs) are studied and compared with those of a conventional Pt counter electrode deposited by thermal reduction on fluorine-doped tin oxide (FTO) glass (TD-Pt/FTO). The DSSC with the SD-Pt/pITO (sample cell) shows a lower charge-transfer resistance than that of the DSSC with the TD-Pt/FTO (reference cell), which leads to an improvement of its fill factor by about 7.6%. The long-term durability test performed for 1000 h at room temperature reveals that the sample cell retains up to 99% of its energy conversion efficiency, while that of the reference cell is degraded by about 7.2%.     

Performance characteristics of dye-sensitized solar cells with counter electrode based on NiP-plated glass and titanium plate

The counter electrodes based on NiP-plated glass and titanium plate were prepared. The performance characteristics of the dye-sensitized solar cells with platinized NiP-plated glass electrode (Pt/NiP electrode) and platinized titanium plate electrode (Pt/TP electrode) were discussed. Pt/NiP electrode and Pt/TP electrode showed the same catalytic activity for triiodide reduction compared with platinized fluorine-doped tin oxide conducting glass electrode (Pt/FTO electrode). However, Pt/NiP electrode and Pt/TP electrode have the advantage over Pt/FTO electrode in reducing the sheet resistance and increasing light reflectivity, which resulted in improving the photovoltaic performance of dye-sensitized solar cells effectively. Compared with the cell using Pt/FTO electrode, the incident photon conversion efficiency of dye-sensitized solar cells with Pt/NiP electrode and Pt/TP electrode was increased by 20% and 5%, respectively, the overall energy efficiency of dye-sensitized solar cells with Pt/NiP electrode and Pt/TP electrode was increased by 32% and 27%, respectively.     

Improved catalytic activity of Pt/rGO counter electrode in In2O3-based DSSC

A platinum/reduced graphene oxide (Pt/rGO) nanocomposite acting as a counter electrode (CE) was fabricated using a chemical bath deposition method for In₂O₃-based dye-sensitized solar cell (DSSC) via sol-gel technique. The report analyzes the morphological and electrochemical impedance spectroscopy of the annealing Pt/rGO films at 350, 400, and 450 °C. Micrograph images obtained from field emission scanning electron microscopy demonstrated the annealed films are highly porous. The energy-dispersive X-ray results show that the carbon atoms were homogeneously distributed on the film annealed at 400 °C. A good photovoltaic performance was exhibited with high photocurrent density of 8.1 mA cm⁻² and power conversion efficiency (η) of 1.68 % at the Pt/rGO CE annealed at 400 °C. The employed electrochemical impedance spectroscopy analysis quantifies that the Pt/rGO films annealed at 400 °C provide more efficient charge transfer with the lowest effective recombination rate and high electron life time, hence improving the performance of Pt/rGO CE.

     

Facile synthesis of nitrogen-doped reduced graphene oxide as an efficient counter electrode for dye-sensitized solar cells

A nitrogen-doped reduced graphene oxide (N-RGO) nanosheet was synthesized by a simple hydrothermal method and characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electrode microscopy. After being deposited as counter electrode film for dye-sensitized solar cells (DSSCs), it is found that the synthesized N-RGO nanosheet has smaller charge-transfer resistance and better electrocatalytic activity towards reduction of triiodide than the reduced graphene oxide (RGO) nanosheet. Consequently, the DSSCs based on the N-RGO counter electrode achieve an energy conversion efficiency of 4.26%, which is higher than that of the RGO counter electrode (2.85%) prepared under the same conditions, and comparable to the value (5.21%) obtained with the Pt counter electrode as a reference. This N-RGO counter electrode offers the advantages of not only saving the cost of Pt itself but also simplifying the process of counter electrode preparation. Therefore, an inexpensive N-RGO nanosheet is a promising counter electrode material to replace noble metal Pt.

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Graphical abstract A nitrogen-doped reduced graphene oxide nanosheet was synthesized by a simple hydrothermal method, which is a promising counter electrode material to replace noble metal Pt.

     

Flexible TiO<Subscript>2</Subscript> nanotube-based dye-sensitized solar cells using laser-drilled microhole array electrodes

Here we report on the growth of TiO₂ nanotube arrays (TNAs) on Ti foil with laser-drilled microhole arrays (MHAs). The MHAs promoted the adhesion of the TNA film to Ti substrate, which is well suited for flexible dye-sensitized solar cells (DSSCs). The MHA photoanode and TNAs were characterized by SEM, 3D optical profiling, XRD and TEM. For such a flexible MHA photoanode, the TNA-based DSSC was assembled using a platinized conductive glass counter electrode, and a conversion efficiency of 3.45% was achieved under AM 1.5 condition. A flexible TNA-based DSSC was also fabricated using a flexible MHA photoanode combined with a platinized indium tin oxide-polyethylene naphthalate counter electrode, which achieved 2.67% photovoltaic conversion efficiency under simulated AM 1.5 sunlight.     

Modification and photovoltaic properties of reduced graphene oxide/acetylene black composite electrode

A simple and high efficient reduced graphene oxide/acetylene black (rGO/ACET) nano-composite electrode was prepared as the substitute of high-cost Pt counter electrode in dye-sensitized solar cells (DSSCs). Surface-modified method called solvent-substituting (SS) was firstly used to avoid agglomeration of rGO sheets. The Brunner-Emmet-Teller (BET)-specific surface area of rGO was increased from 195.823 to 355.210 m²/g after modifying with ethanol. Then ACET particles were introduced between rGO layers to improve the electronic transportation properties. The chemical compositions, microstructures, and pore size distributions of rGO/ACET composites were investigated. Electrochemical impedance spectroscopy (EIS) indicated that rGO/ACET counter electrode had a lower charge transfer resistance (R_ct) and its S-shaped current–voltage curves disappeared obviously. The highest power conversion efficiency up to 6.62% was achieved for the DSSCs with rGO/ACET nano-composite counter electrode.     

Prickly polyaniline nano/microstructures as the efficient counter electrode materials for dye-sensitized solar cells

Two kinds of prickly polyaniline samples, prickly polyaniline nanorods and microgranules, are prepared through the chemically oxidative polymerization method by regulating the concentration of aniline. Scanning electron microscopy images indicate that the diameter of prickly polyaniline nanorods (PPNRs) is about 80 nm and the size of prickly polyaniline microgranules (PPMGs) is about 400 nm. The as-prepared prickly polyaniline samples are subsequently explored as the Pt-free counter electrode materials for dye-sensitized solar cells (DSCs). Electrochemical impedance spectroscopy and cyclic voltammetry measurements demonstrate that PPNR electrode displays superior electrocatalytic activity for the I₃ ^? reduction reaction to PPMG electrode, which can be attributed to the unique prickly nanorod structure that provides abundant electrocatalytic active sites and the fast charge transport pathway simultaneously. As a consequence, the DSC fabricated with PPNR counter electrode achieves a high conversion efficiency of 6.86% under illumination of 100 mW cm^?2, which is close to the efficiency of a Pt electrode-based device. This work presents a promising way to develop Pt-free and high-efficiency counter electrode in DSCs.     

Layer-by-layer Au nanoparticles as a Schottky barrier in a water-based dye-sensitized solar cell

We fabricated layer-by-layer gold nanoparticles (Au NPs) onto an electrode as a Schottky barrier in a water-based dye-sensitized solar cell. The Maxwell–Garnett equation was used to fit the characteristics of the Au film. The short-circuit current for four layers of Au NPs in a water-based dye-sensitized solar cell (DSSC) ranges from 2.76 mA/cm² to 5.96 mA/cm², which is due to the Schottky barrier reducing the number of electrons going from the semiconductor back to either the dye or the electrolyte. The efficiency of photo-electric conversion for four layers of Au NPs in water-based DSSC can be enhanced from 0.26% up to 0.95%. PACS 85.30.Hi; 82.47.Jk; 73.63.-b; 81.16.-c; 78.67.Bf     

新型碳材料在钙钛矿太阳电池中的应用研究进展

新型碳材料如石墨烯及其氧化物、碳纳米管、富勒烯及石墨炔等因其优异的热学、力学、电学、光学性能成为了钙钛矿太阳电池研究的又一亮点. 本文总结了新型碳材料在钙钛矿太阳电池对电极、电子传输材料及空穴传输材料中的研究进展, 新型碳材料的引入有效地提高了钙钛矿电池的性能, 为下一步新型碳材料的应用开发以及钙钛矿电池器件的研究提供了新的思路.     

Dye-sensitized solar cells based on ZnO nanowire array/TiO2 nanoparticle composite photoelectrodes with controllable nanowire aspect ratio

The ZnO nanowire (NW) array/TiO₂ nanoparticle (NP) composite photoelectrode with controllable NW aspect ratio has been grown from aqueous solutions for the fabrication of dye-sensitized solar cells (DSSCs), which combines the advantages of the rapid electron transport in ZnO NW array and the high surface area of TiO₂ NPs. The results indicate that the composite photoelectrode achieves higher overall photoelectrical conversion efficiency (η) than the ZnO NW alone. As a result, DSSCs based on the ZnO NW array/TiO₂ NP composite photoelectrodes get the enhanced photoelectrical conversion efficiency, and the highest η is also achieved by rational tuning the aspect ratio of ZnO NWs. With the proper aspect ratio (ca. 6) of ZnO NW, the ZnO NW array/TiO₂ NP composite DSSC exhibits the highest conversion efficiency (5.5 %). It is elucidated by the dye adsorption amount and interfacial electron transport of DSSCs with the ZnO NW array/TiO₂ NP composite photoelectrode, which is quantitatively characterized using the UV-Vis absorption spectra and electrochemical impedance spectra. It is evident that the DSSC with the proper aspect ratio of ZnO NW displays the high dye adsorption amount and fastest interfacial electron transfer.     

Zinc oxide nanostructures for applications as ethanol sensors and dye-sensitized solar cells

ZnO nanostructures were prepared by thermal oxidation technique for applying as ethanol sensors and dye-sensitized solar cells. To improve sensitivity of the sensor based on ZnO nanostructures, gold doping was performed in ZnO nanostructures. Gold-doped with 0%, 5%, and 10% by weight were investigated. The improvement of sensor sensitivity toward ethanol due to gold doping was observed at entire operating temperature and ethanol concentration. The sensitivity up to 145 was obtained for 10% Au-doped ZnO sensor. This can be explained by an increase of the quantity of oxygen ion due to catalytic effect of gold. Also, it was found that oxygen ion species at the surface of the Au-doped ZnO sensor remained O²⁻ as pure ZnO sensor. For dye-sensitized solar cell application, the dye-sensitized solar cell structure based on ZnO as a photoelectrode was FTO/ZnO/Eosin-Y/electrolyte/Pt counter electrode. ZnO with different morphologies of nanobelt, nano-tetrapod, and powder were investigated. It was found that DSSCs with ZnO powder showed higher photocurrent, photovoltage and overall energy conversion efficiencies than that of ZnO nanobelt and ZnO nano-tetrapod. The best results of DSSCs were the short circuit current (J_sc) of 1.25 mA/cm², the open circuit voltage (V_oc) of 0.45 V, the fill factor (FF) of 0.65 and the overall energy conversion efficiency (η) of 0.68%.     

二硒化铁/还原氧化石墨烯的制备及其在染料敏化太阳能电池中的应用

通过水热反应合成出二硒化铁/还原氧化石墨烯(FeSe₂/rGO)复合材料, 并将其作为对电极材料应用于染料敏化太阳能电池(DSSC). 利用X射线衍射、拉曼光谱、场发射扫描电子显微镜和高分辨透射电子显微镜对FeSe₂/rGO的结构和形貌进行了表征. 利用循环伏安法、电化学阻抗谱和Tafel曲线测试分析了FeSe₂/rGO对电极的电催化活性. 结果表明: FeSe₂呈纳米棒结构, 长度在100-200 nm之间, 且紧密地附着在rGO 的表面, FeSe₂/rGO对电极对I₃^-的还原具有很好的催化活性. 电池的J-V曲线测试显示: 基于FeSe₂/rGO对电极的DSSC的转换效率达到了8.90%, 相比基于单纯的FeSe₂对电极的DSSC(7.91%)和rGO对电极的DSSC(5.24%)都有了显著提高, 甚至优于铂对电极的DSSC(8.52%).     

Interface modification of MoS2 counter electrode/electrolyte in dye-sensitized solar cells by incorporating TiO2 nanoparticles

To achieve the high efficiency in dye-sensitized solar cells (DSSCs), the interface modification of MoS₂ counter electrode (CE)/electrolyte should be carried out. Making the modified MoS₂ CE by incorporating TiO₂ nanoparticles provides possibilities to enhance electrocatalytic activity. The DSSCs with the MoS₂/TiO₂ CE show enhanced performance compared with DSSCs with the MoS₂ CE. The experimental results revealed that the MoS₂/TiO₂ nanocomposite influences on the power conversion efficiency by enhancing electrocatalytic activity and increasing the active surface area that serve to increase the short circuit current. This understanding can provide guidance for the development of highly efficient DSSCs with platinum-free CEs.     

Sensitized solar cells based on natural dyes

We have employed several natural dyes for application in dye sensitized solar cells (DSSC). Spinach, beet, red cabbage and strawberry are well known and have been already used. We then checked the opportunity to realize good DSSC with dyes available in Tunisia: Henna and Mallow (Mloukhya). Henna is a herb which has interesting reddish brownish dyeing properties used since antiquity for traditional decoration of skin, hair and fingernails in the Middle East and North Africa. The mallow is a green vegetable which is widely consumed in the same region. The optical absorption of the extracted dyes diluted in ethanol or distilled water were measured using UV–Vis spectrophotometer. The absorption in beet and red cabbage is more significant compared to the other dyes. Mallow and henna dyes present a noticeable band in the region 660 nm. Infra-red spectroscopy measurements were done to probe the structure and dynamics in our used dyes. In this paper, we present the steps followed in the making of our solar cells. The DSSC were assembled using two glass plates (supporting electrode and counter electrode) which are coated with transparent conducting oxide (TCO). The counter electrode is coated by a catalyst Pt (Platinum) to speed up the redox reaction with the electrolyte solution. The typical J–V curves of our solar cells under AM 1.5 using a density of power 100 mW/cm² were measured. Cells using henna and mallow as dyes present less degradation with time in the photoelectric characteristics. The mallow cell shows a good fill factor of 55% and a noticeable photoelectric conversion efficiency of 0.215%.     

新型多孔凝胶电解质的制备及其在准固态柔性基染料敏化太阳电池中的应用

制备了一种新型多孔聚丙烯酸/十六烷基三甲基溴化铵聚吡咯凝胶电解质,并将其应用于柔性基染料敏化太阳电池(DSSC)。通过扫描电镜表征、热重分析测试、电化学性能测试和柔性电池光电性能测试等手段,分析了凝胶电解质对柔性基DSSC的光电性能影响。研究结果表明:随着聚吡咯的引入,提高凝胶电解质导电性以及催化电解质中的I-/I3-离子电对等性能,最终在100mW/cm2[大气质量(AM)1.5]光照条件下,测得基于该准固态凝胶电解质的柔性基DSSC光电转换效率达1.28%。     

An alternative flexible electrode for dye-sensitized solar cells

With comparable transparency, flexibility, but a better conductivity, metal-mesh based PEN film provides an alternative low-cost electrode material to the conventional ITO/PEN film for flexible solar cell system. In this article, counter electrodes (CEs) prepared by coating metal-mesh/PEN with a mixture of PEDOT:PSS and carbon black nanoparticle (200?C400?nm) were utilized in flexible dye-sensitized solar cells (DSCs). A high efficiency of 5.5?% was achieved with the DSC based on the metal-mesh/PEN CE, rivaling that of the DSC based on ITO/PEN CE.     

Natural dye-based photoelectrode for improvement of solar cell performance

In the present paper, photovoltaic studies of dye-sensitized solar cells (DSSCs) based on betacyanin/TiO₂ and betacyanin/WO₃–TiO₂ have been done. The cell performances were compared through I–V curves and wavelength dependant photocurrent measurements for the two new types of DSSCs. The TiO₂-coated DSSC showed the photovoltage and photocurrent of 300 mV and 4.96 mA/cm², whereas the cell employing WO₃–TiO₂ photoelectrode showed the values 435 mV and 9.86 mA/cm², respectively. The conversion efficiency of TiO₂ based dye-sensitized solar cell was found to be 0.69 %, while WO₃–TiO₂-based cell exhibited a higher conversion efficiency of 2.2 %. The better performance of the WO₃–TiO₂ dye-sensitized solar cell photoelectrode is thought to be due to an inherent energy barrier at the electrode/electrolyte interface leading to the reduced recombination of photoinduced electrons.     

One-step hydrothermal synthesis of feather duster-like NiS@MoS<Subscript>2</Subscript> with hierarchical array structure for the Pt-free dye-sensitized solar cell

Novel feather duster-like nickel sulfide (NiS) @ molybdenum sulfide (MoS₂) with hierarchical array structure is synthesized via a simple one-step hydrothermal method, in which a major structure of rod-like NiS in the center and a secondary structure of MoS₂ nanosheets with a thickness of about 15–55 nm on the surface. The feather duster-like NiS@MoS₂ is employed as the counter electrode (CE) material for the dye-sensitized solar cell (DSSC), which exhibits superior electrocatalytic activity due to its feather duster-like hierarchical array structure can not only support the fast electron transfer and electrolyte diffusion channels, but also can provide high specific surface area (238.19 m² g^?1) with abundant active catalytic sites and large electron injection efficiency from CE to electrolyte. The DSSC based on the NiS@MoS₂ CE achieves a competitive photoelectric conversion efficiency of 8.58%, which is higher than that of the NiS (7.13%), MoS₂ (7.33%), and Pt (8.16%) CEs under the same conditions.

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Graphical abstract Novel feather duster-like NiS@MoS₂ hierarchical structure array with superior electrocatalytic activity was fabricated by a simple one-step hydrothermal method.