染料敏化太阳能电池非铂对电极研究进展

对电极作为染料敏化太阳能电池（dye-sensitized solar cell,DSSC）的重要组成部分,对电极材料性能的好坏直接影响着染料敏化太阳能电池的光电转化效率。最常使用的对电极电催化材料是贵金属铂,而铂十分稀少而且价格昂贵,并且铂很容易被碘电解液腐蚀,不利于染料敏化太阳能电池的产业化发展。本文重点综述了2010年以来染料敏化太阳能电池非铂对电极的研究成果,简要说明了对电极在染料敏化太阳能电池中的作用,详细介绍了非铂金属、碳材料、导电聚合物和无机化合物等对电极材料,分析了各类非铂对电极材料的特点、制备工艺、发展前景、优缺点和改进措施。最后提出,继续开发各种成本低、原料易得以及稳定高效的新型非金属对电极材料仍是今后染料敏化太阳能电池研究的一个重要方向。     

Effect of carbonaceous counter electrodes on the performance of ZnO-graphene nanocomposites based dye sensitized solar cells

With many advantages like low-cost preparation, excellent electrical properties, and high catalytic activity; carbon allotropes are the most expected carbon materials to substitute the expensive Platinum (Pt) as counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). In the present study, the photovoltaic behaviors of DSSCs fabricated with graphene, multiwalled carbon nanotubes (MWCNTs), and Pt films CEs, respectively, were compared. The graphene and MWCNTs CEs films were prepared by doctor blading the graphene and MWCNTs pastes on Indium tin oxides (ITOs) glass substrates. The structural, morphological, and compositional properties of these carbon CEs viz. graphene and MWCNTs were investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), and energy dispersive X-ray (EDX), respectively. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed for the examination of electrochemical and catalytic properties of Pt as well as carbonaceous CEs. These low-cost graphene and MWCNTs CEs were employed in the sandwich-structured DSSCs having ZnO-graphene nanocomposite films as photoanodes. The photoconversion efficiency (η) values of as prepared DSSCs were measured under AM 1.5 illumination (100?mW?cm^?2). The DSSCs with graphene CE and MWCNTs CE performed with efficiency values of 2.26% and 2.04%, respectively. The performance of these carbonaceous CEs are comparative to that of Pt CE which indicates the practicability of carbon based nanomaterials in DSSCs as low cost alternatives to the expensive Pt.     

Dye-sensitized solar cells employing polymers

Dye-sensitized solar cells (DSSCs) are of interest due to their potential use as inexpensive and environmentally friendly photovoltaic (PV) devices with acceptable power conversion efficiency (PCE). Platinum (Pt) metal is, traditionally, the preferred material for the counter electrode (CE) component of DSSCs, however, further development of iodide/triiodide (I⁻/I₃⁻) based liquid-electrolyte DSSCs using Pt remains challenging due to the high cost of this scarce metal and its susceptibility to corrosion. Additional concerns include solvent leakage and low chemical stability resulting from volatile liquid electrolyte used in DSSCs. In order to counteract this issue, polymer electrolytes or hole-transporters with higher mobilities are employed as a replacement for liquid electrolytes. In this regard, polymers can serve as efficient CE materials by replacing the platinized electrode in liquid-electrolyte DSSCs, while also substituting for the liquid electrolytes as polymer electrolytes or hole-transporters in solid-state or quasi solid-state DSSCs. Considering the fragility and shape restrictions of glass substrates, polymer substrates may also be used to replace rigid glass substrates, providing more flexible DSSCs. Herein, applications of the polymers as cell components (CEs, polymer electrolytes or hole-transporter, and plastic substrates) in DSSCs are discussed, with special focus on the role that polymers play in DSSCs and widely accepted reports of PV performance. The current understanding of the factors and strategies involved in improving the performance of polymers in DSSCs are reviewed and analyzed. In addition, the benefits, challenges and potential utility of polymers for use in DSSCs are assessed.     

Electrophoretic deposition of carbon nanotubes films as counter electrodes of dye-sensitized solar cells

Carbon nanotubes (CNTs) films have been successfully fabricated by electrophoretic deposition (EPD) technique and used as counter electrodes of dye-sensitized solar cells (DSSCs). The CNTs counter electrodes consisting of a large number of bamboo-like structures with defect-rich edge planes exhibit a highly interconnected network structure with high electrical conductivity and good catalytic activity. A high photovoltaic conversion efficiency of 7.03% is achieved for DSSCs based on the CNTs counter electrodes, which is comparable to the cell based on conventional Pt counter electrode at one sun (AM 1.5G, 100 mW cm⁻²). The results suggest that the present synthetic strategy provides a potential feasibility for the fabrication of low-cost flexible counter electrodes of DSSCs using a facile deposition technique from an environmentally “friendly” solution at low temperature.     

Ordered mesoporous carbon-decorated reduced graphene oxide as efficient counter electrode for dye-sensitized solar cells

Due to the advantages of both rapid electron transport of reduced graphene oxide (rGO) sheet and high catalytic performance of ordered mesoporous carbon (OMC), composites of OMC with rGO (G@OMC) have been prepared through the hard-template approach and used as efficient counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). When compared with pure OMC, the as-obtained G@OMC composites exhibit a higher electrocatalytic activity for the reduction of triiodide, owing to the synergetic effect between rGO and OMC. As a consequence, the DSSCs assembled with this G@OMC (CE show an improved photovoltaic conversion efficiency of 6.38% compared with 5.67% for DSSCs assembled with OMC CE, which could compete with the efficiency (7.05%) produced by the Pt CE under the same conditions.     

染料敏化太阳能电池碳基对电极的研究进展

作为第3代新型薄膜太阳能电池的代表之一,染料敏化太阳能电池(DSSCs)是近年来光伏领域的一个研究热点.对电极是DSSCs的一个关键组成部分,其功能是收集来自外电路的电子并实现电解质中I3-的催化还原.通常,DSSCs的对电极为贵金属铂(Pt),但Pt的储量有限、价格高昂、在电化学环境中稳定性差,这些缺点很大程度上增加...     

One- and two-dimensional carbon nanomaterials as counter electrodes for dye-sensitized solar cells

This study examines the dye-sensitized solar cells (DSSCs) equipped with 1-D carbon nanotubes (CNTs) and 2-D graphene nanosheets (GNs) carbon counter electrodes. Imperfect defects were attached to the sidewall or both the ends of the CNTs, and the edges of the GNs were analyzed by X-ray diffraction and Raman spectroscopy. When compared with the GN-based counter electrode, CNT-based counter electrodes showed a better improvement in the incident photon-to-current efficiency and power conversion efficiency of the cells. This enhancement of cell performance can be attributed to the combination of CNT network and spherical graphite bottom layer, favoring dye adsorption, catalytic redox activity, and 1-D charge-transfer path length. Such carbon configuration as counter electrode provides a potential feasibility for replacing metallic Pt counter electrodes.     

Recent Progress on Reduced Graphene Oxide-Based Counter Electrodes for Cost-Effective Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) are one type of highly efficient low-cost solar cells among third-generation photovoltaic devices. Replacing the expensive components of DSSCs with alternative inexpensive and earth-abundant materials would further reduce their price in the solar cell market. Recently, graphene-based low-cost counter electrodes (CEs) have been developed, which could serve as a potential alternative to the expensive platinum-based CEs. In this review article, we have summarized recent research on various reduced graphene oxide (rGO)-based composite CE materials, methods for their synthesis, their catalytic activity, and the effective utilization of such CEs in DSSCs. The photovoltaic performance of DSSCs made of rGO-based composite CEs were compared with the reference Pt-based cells, and the photovoltaic parameters are summarized in tables.     

Graphene aerogels as a highly efficient counter electrode material for dye-sensitized solar cells

Graphene aerogels (GAs) prepared with an organic sol–gel process, possessing a high specific surface area of 814 m²/g and a high electric conductivity of 850 S/m, are applied as a counter electrode material for dye-sensitized solar cells (DSSCs). The performance of the GA as the counter electrode material is found to be dependent on its film thickness, with thicker films offering more surface areas for the involved catalytic reduction reaction but at the same time increasing the charge and mass transport resistances. At an optimum GA film thickness of 4.9 μm, a power conversion efficiency of 96% of that achieved with a Pt counter electrode based DSSC is obtained. In addition, a thinner GA film of 1.7 μm, when loaded with Pt of 1 mol% through a photo-reduction process, achieves a power conversion efficiency of 98% of that obtained with a Pt counter electrode based DSSC. The excellent performances of the GA-based counter electrodes are manifested with electrochemical impedance analyses and cyclic voltammetry based catalytic activity analyses.     

Improved photocurrent of a poly (3,4-ethylenedioxythiophene)-ClO₄⁻/TiO₂ thin film-modified counter electrode for dye-sensitized solar cells

We prepared a poly(3,4-ethylenedioxythiophene) (PEDOT)-ClO??-supported TiO? thin-film electrode as a counter electrode on a transparent conductive oxide glass electrode for a dye-sensitized solar cell (DSSC) using a combination of sol-gel and electropolymerization methods. The photocurrent-voltage characteristics indicate that DSSCs with PEDOT-ClO??/TiO? thin-film counter electrodes had a high photovoltaic conversion efficiency similar to that of PEDOT-ClO??/TiO? particle composite-film electrodes. Furthermore, it was found that the photocurrent was increased by attaching a reflector to the opposite side of the transparent counter electrode.     

Recent Advances in Counter Electrodes for Thiolate-mediated Dye-sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) based on disulfide/thiolate (T₂/T⁻) redox couples have attracted remarkable attention due to their high efficiency and low cost. As an indispensible part of DSSCs, counter electrode (CE) design plays a crucial role in high efficiency DSSCs. This mini-review paper selectively reviews the recent advances in T-mediated DSSCs using novel CE (namely cathode) materials, mainly including noble metal platinum (Pt), carbon materials, transition metal compounds (TMCs), polymers, and hybrids, thus highlighting the merits and demerits of alternative Pt catalysts, and the prospects and challenges of Pt-free CEs for the development of high-performance and low-cost DSSCs.     

9种树叶生物炭作为染料敏化太阳电池对电极的光电性能

将9种由树叶经单步热解获得的生物炭作为对电极催化材料引入染料敏化太阳电池（DSSC）,并在分析生物炭的组织结构和电化学性能的基础上,着重探讨了引起器件光电性能差异的内在原因。结果表明：9种树叶热解获得的生物炭组装的DSSC的转换效率在1.00%~1.85%之间,其中棕叶最佳,樟树叶和杨树叶其次,三者的转换效率均高于1.3%,随后依次为枫叶、红继木叶、椿树叶、杉树叶和松针,桂叶最低。生物炭的孔隙结构是引起相应器件光电性能各异的主要原因。由于棕叶生物炭具有独特的取向孔隙,能缩短电解质扩散距离以及提升催化活性,因此其器件的转换效率最佳。此外,9种生物炭器件的转换效率均高于石墨器件（0.77%）。更优的光电性能主要归功于生物炭具有的多级孔结构和玻璃态碳骨架。     

Fabrication and characterization of carbon-based counter electrodes prepared by electrophoretic deposition for dye-sensitized solar cells

Three different carbon-based counter electrodes are investigated in light of catalytic activities such as electrochemical frequencies and interface impedances. We fabricated carbon-based counter electrodes of dye-sensitized solar cells [DSSCs] using graphene, single-walled carbon nanotubes [SWNTs], and graphene-SWNT composites by electrophoretic deposition method. We observed the optical and electrochemical properties of the carbon-based counter electrodes. The DSSC with the graphene-deposited counter electrode demonstrated the best conversion efficiency of 5.87% under AM 1.5 and 1 sun condition. It could be utilized for a low-cost and high-throughput process for DSSCs.     

Water-soluble polyaniline/graphene prepared by in situ polymerization in graphene dispersions and use as counter-electrode materials for dye-sensitized solar cells

Water-soluble polyaniline/graphene nanocomposites have been prepared via a simple in situ polymerization of aniline in graphene dispersion. TEM measurement confirmed that polyaniline was homogeneously coated on the graphene sheets. The nanocomposites solution can be used for film fabrication by common technology, such as drop coating. When these different polyaniline/graphene nanocomposites were applied as the counter electrode materials for dye-sensitized solar cells, the short-circuit current density and power-conversion efficiency of the devices were measured to be 12.19 mA cm⁻² and 4.46%, respectively, which was comparable to 5.71% for the cell with a Pt counter electrode under the same experimental conditions.     

Graphene wrapped copper–nickel nanospheres on highly conductive graphene film for use as counter electrodes of dye-sensitized solar cells

A novel architecture of graphene wrapped copper–nickel (Cu–Ni) nanospheres (NSs)/graphene film was proposed to be TCO- and Pt-free counter electrode (CE) with high electrocatalytic activity for dye-sensitized solar cells (DSSCs). The novel architecture CE is composed of highly conductive graphene film, Cu–Ni alloy NSs and the wrapping graphene on the surface of alloy NSs. The graphene film as an electrically conductive layer was synthesized by chemical vapor deposition (CVD) on the insulating SiO₂ substrate, and graphene wrapped Cu–Ni alloy catalyst NSs on the graphene film were in situ formed by the reduction of Cu–Ni acetate and graphene growth using CVD. The graphene wrapped Cu–Ni NSs/graphene film CE shows much superior electrocatalytic activity, compared with graphene film, and the power conversion efficiency of 5.46% was achieved in DSSC devices, which is close to that of Pt/FTO electrode (6.19%). Therefore, the novel architecture of graphene wrapped Cu–Ni NSs/graphene film CE may be used as Pt- and TCO-free CEs for low-cost, high performance DSSCs.     

Preparation and characterization of poly(o‐anisidine) with the influence of surfactants on stainless steel by electrochemical polymerization as a counter electrode for dye‐sensitized solar cells

Efficient fast electron transfer from counter electrode to an electrolyte is a key process during the operation of dye‐sensitized solar cells (DSSCs). We introduce a surfactants assisted electro‐polymerized poly(o‐anisidine) (POA) counter electrodes (CE) for DSSCs. Commencing the electrochemical impedance spectroscopy, the POA/sodium dodecyl sulphate (SDS) CE exhibited very low series and charge‐transfer resistance. This is due to high electrocatalytic activity confirmed by cyclic voltammetry, surface area and the conductivity of the stainless steel film. The photovoltaic performance of POA/SDS counter electrode shows an energy conversion efficiency of 2.5% under 1 sun illumination. Short‐term stability test for POA/SDS point out that CE have almost uphold its initial performance. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42310.     

Effect of Transition-Metal Ion Doping on Electrocatalytic Activities of graphene/polyaniline-M2+ (Mn2+, Co2+, Ni2+, and Cu2+) Composite Materials as Pt-Free Counter Electrode in Dye-Sensitized Solar Cells

A series of graphene/polyaniline-M²⁺ (M²⁺ = Mn²⁺, Co²⁺, Ni^2+, and Cu²⁺) composite counter electrodes were synthesized by doping transition-metal ions in polyaniline and graphene for dye-sensitized solar cells (DSSCs). The counter electrodes showed significantly high photoelectric conversion efficiency of 5.38% (Mn²⁺), 4.65% (Co²⁺), 4.00% (Ni²⁺), and 2.49% (Cu²⁺). The catalytic activities of graphene/polyaniline-M²⁺ electrodes were evaluated using cyclic voltammetry, Nyquist plots, and Tafel polarization. The chemical characteristics and surface morphology of graphene/polyaniline-M²⁺ composite materials were determined by infrared spectroscopy and scanning electron microscopy. These results indicate a potential application of ion-doped polyaniline as the counter electrode in cost-effective DSSCs.     

High-performance and low platinum loading electrodeposited-Pt counter electrodes for dye-sensitized solar cells

This study demonstrates platinum (Pt) counter electrodes with low charge-transfer resistance (R_ct), low Pt loading and high active surface area can be obtained within 30 s by using the direct-current deposition in the presence of 3-(2-aminoethylamino)propyl-methyldimethoxysilane (Me-EDA-Si) as an additive. The addition of appropriate Me-EDA-Si can not only enhance the current efficiency but also inhibit the growth of semicircle-like grains, thus resulting in Pt electrode with high active surface area. Consequently, the dye-sensitized solar cells (DSSCs) fabricated with so-prepared Pt electrodes exhibited cell efficiency of 7.39% while 0.01 vol% Me-EDA-Si was added, which is much superior to that with sputtered-Pt electrodes under the same assembly conditions.     

Electrochemical photovoltaic cells—review of recent developments

Photoelectrochemistry is attracting extensive attention from scientists worldwide for its use in converting light energy into electricity in electrochemical photovoltaic cells, the most common form of which, dye sensitized solar cells (DSSCs), can offer both flexibility and transparency. Their efficiencies are now comparable with amorphous silicon solar cells but at a much lower cost. This review covers not only the fundamentals of electrochemical photovoltaic cell operation but also recent advances in research and development for industrial applications. The most recent research topics relating to DSSCs, for example, applications of nanostructured n‐type semiconducting electrodes, ionic liquid electrolytes and graphene and carbon nanotube electrodes are all included. In addition, the storage of electrochemical energy by electrochemical photovoltaic cells has also been reviewed. Copyright © 2010 Society of Chemical Industry     

In situ electrochemical synthesis of a poly(o‐anisidine) counter electrode for a dye‐sensitized solar cell

Poly(o‐anisidine) (POA) counter electrodes (CEs) were fabricated by potentiodynamic deposition and incorporated into platinum (Pt)‐free dye‐sensitized solar cells (DSSCs). A different sweep number had great impact on the morphology and electrocatalytic activity of the POA films. The POA film fabricated by 25 sweep cycles was observed to have a highly porous morphology, and this resulted in a lower charge‐transfer resistance of 57 cm² in comparison with the Pt CE. The DSSC assembled with the POA CE showed a higher photovoltaic conversion efficiency of 1.67% compared to 1.2% for the DSSC with the Pt CE under full sunlight illumination. Therefore, the high active surface area of the 25‐sweep‐segmented POA film could be considered a promising alternative CE for use in DSSCs because of its high electrocatalytic performance and electrochemical stability. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42041.