PEDOT基对电极染料敏化太阳能电池研究进展

染料敏化太阳能电池(DSSC)是新型太阳能电池的研究热点之一,其优异的弱光发电性能被不断探索,同时透明及柔性DSSC在可穿戴设备上的应用也与日俱增。DSSC的循环依靠对电极的作用才能及时高效地完成,因此对电极材料的选择尤为关键。近几年研究者们对对电极材料的研究不断深入,其中可作为DSSC对电极材料使用的高分子导电聚合物聚3,4-乙撑二氧噻吩(PEDOT)因其高导电性、对电解质的催化能力、透明性和柔性等特点受到广泛关注。以含PEDOT或掺杂PEDOT对电极的DSSC为对象,阐述了PEDOT对电极的制备方法,并总结了近几年PEDOT作为DSSC对电极的研究进展。在此基础上,提出未来在电池效率突破研究中应以原位聚合法制备PEDOT对电极为主,以及在大规模工业化生产中应以物理涂覆法为主的观点,为PEDOT对电极DSSC的研究提供依据。     

染料敏化太阳能电池无FTO煤基炭对电极的研究

分别以气煤、焦煤、瘦煤为原料制备了低成本、高性能煤基炭对电极(counter electrodes, CEs), 并使用煤基炭CE同时代替导电玻璃基底和催化层, 分别考察了浸渍和表面修饰对煤基炭CE结构和光电性能的影响。采用X射线衍射、扫描电镜和电化学阻抗谱等表征手段, 对煤基炭CE的结构和性能进行了表征。结果表明: 浸渍后煤基炭CE形成了底层致密表层多孔的一体化结构; 经过表面修饰的煤基炭CE表现出良好的光电性能, 其开路电压(V_oc)、短路电流密度(J_sc)和填充因子(FF)分别为0.79 V、13.48 mA/cm²和0.67, 光电转化效率(η)达到了7.16%, 与传统Pt电极的效率相当, 比石墨电极效率提高30%。煤基炭CE是传统Pt/FTO电极的良好替代材料。     

染料敏化太阳能电池过渡金属化合物对电极制备方法研究进展

染料敏化太阳能电池(dye-sensitized solar cells, DSSCs)作为制作工艺简易, 成本低廉, 环境友好的新型太阳能电池, 其发展一直备受关注。对电极作为DSSC的核心部件之一, 其制备工艺会直接影响到DSSC的发展和应用。以低成本高性能的催化材料代替传统的贵金属Pt对电极是降低DSSC生产成本的有效途径之一。具有类Pt催化性能的过渡金属化合物(TMCs)由于种类繁多, 制备方式简单多样, 近年来成为DSSC对电极研究中的热点。本文综述了DSSC过渡金属化合物对电极的最新研究进展, 总结概括了过渡金属化合物对电极的制备方法以及性能特点, 并对其发展方向和应用前景进行了分析。     

基于不同浓度铂对电极的染料敏化太阳能电池的性能研究

染料敏化太阳能电池对电极上用于催化的铂的浓度对电池的光电转换性能有重要的影响,特别是当光从对电极射入染料敏化太阳能电池(DSSC)时.制备了不同铂浓度对电极的电池,研究了光从对电极入射时,铂对内部阻抗、光吸收效率等的影响,优化出最佳的铂浓度.结果表明,10mmol/L为最佳对电极入射铂浓度,在一定浓度范围内,开路电压(...     

Pt‐Free Counter Electrode for Dye‐Sensitized Solar Cells with High Efficiency

Dye‐sensitized solar cells (DSSCs) have attracted widespread attention in recent years as potential cost‐effective alternatives to silicon‐based and thin‐film solar cells. Within typical DSSCs, the counter electrode (CE) is vital to collect electrons from the external circuit and catalyze the I₃^? reduction in the electrolyte. Careful design of the CEs can improve the catalytic activity and chemical stability associated with the liquid redox electrolyte used in most cells. In this Progress Report, advances made by our groups in the development of CEs for DSSCs are reviewed, highlighting important contributions that promise low‐cost, efficient, and robust DSSC systems. Specifically, we focus on the design of novel Pt‐free CE catalytic materials, including design ideas, fabrication approaches, characterization techniques, first‐principle density functional theory (DFT) calculations, ab‐initio Car‐Parrinello molecular dynamics (CPMD) simulations, and stability evaluations, that serve as practical alternatives to conventional noble metal Pt electrodes. We stress the merits and demerits of well‐designed Pt‐free CEs, such as carbon materials, conductive polymers, transition metal compounds (TMCs) and their corresponding hybrids. Also, the prospects and challenges of alternative Pt catalysts for their applications in new‐type DSSCs and other catalytic fields are discussed.     

Synthesis of novel counter electrode by combination of mesoporous–macroporous CZTS films for enhanced performance of quantum-dots sensitized solar cells

This present study aims to manifest the potential of CZTS films as a low-cost counter electrode (CE) in quantum-dots sensitized solar cells (QDSSCs). Hitherto, numerous researchers have reported the application of either CZTS nano particles or films as a counter electrode in dye sensitized solar cells. However, its use in QDSSCs is scarcely reported. Herein, CdS quantum-dots sensitized ZnO film is used as photoanode. In the beginning, as a counter electrode, two different CZTS films (mesoporous and macroporous) are prepared using two different deposition techniques (spray pyrolysis and spin coating, respectively). For the meso-CZTS film, high V_OC and FF are observed, whereas, for the macro-CZTS film, high J_SC is observed. Hence, to take the advantage of both, subsequently, a film (meso–macro-CZTS) comprising mesoporous film upon the macroporous film is prepared and applied as CE. For the meso–macro-CZTS, substantial enhancement in power conversion efficiency (PCE) is observed. Additionally, to compare the results with commonly reported CEs (SnS/FTO and Pt–FTO) are also applied in QDSSCs. Moreover, to improve the PCE combination of these CEs along with meso–macro-CZTS, for instance, CZTS/SnS/FTO and CZTS/Pt–FTO are also applied as CE. The highest efficiency of 4.34% is achieved with CZTS/Pt–FTO.     

碳材料在染料敏化太阳能电池和钙钛矿太阳能电池对电极中的应用进展

染料敏化太阳能电池和钙钛矿太阳能电池是目前太阳能电池领域的研究热点,但这两种电池中使用的传统对电极材料,如Pt和Au等稀有且价格昂贵,不利于大规模量产。碳材料作为除Pt,Au等之外的另一种候选材料,其种类丰富且成本低廉,作为对电极应用在这两类电池中具有逐渐接近甚至超越传统电池的光电转换效率,表现出良好的应用前景。本文综述了作为两类电池对电极的碳材料具备的结构、性能及对电池光伏性能的影响,着重介绍各种形式的碳材料应用于对电极的最新研究进展,并指出现有研究存在的局限性与待解决的问题,讨论了碳材料对电极未来的研究方向。     

Highly Electrocatalytic Activity of RuO2 Nanocrystals for Triiodide Reduction in Dye‐Sensitized Solar Cells

Dye‐sensitized solar cells (DSCs) are promising alternatives to conventional silicon devices because of their simple fabrication procedure, low cost, and high efficiency. Platinum is generally used as a superior counter electrode (CE) material, but the disadvantages such as high cost and low abundance greatly restrict the large‐scale application of DSCs. An efficient and sustainable way to overcome the limited supply of Pt is the development of high‐efficiency Pt‐free CE materials, which should possess both high electrical conductivity and superior electrocatalytic activity simultaneously. Herein, for the first time, a two‐step strategy to synthesize ruthenium dioxide (RuO₂) nanocrystals is reported, and it is shown that RuO₂ catalysts exhibit promising electrocatalytic activity towards triiodide reduction, which results in comparable energy conversion efficiency to that of conventional Pt CEs. More importantly, by virtue of first‐principles calculations, the catalytic mechanism of electrocatalysis for triiodide reduction on various CEs is investigated systematically and it is found that the electrochemical triiodide reduction reaction on RuO₂ catalyst surfaces can be enhanced significantly, owing to the ideal combination of good electrocatalytic activity and high electrical conductivity.     

量子点敏化太阳能电池对电极材料的研究进展

量子点敏化太阳能电池(Quantum Dot-Sensitized Solar cells, QDSCs)制备工艺简单, 制造成本低廉, 是一种有希望的新型太阳能电池。QDSCs利用量子点具有光谱吸收强、尺寸可调和多激子效应等优点, 能够提高其光电转换效率; 同时, 利用无机量子点替代染料作为敏化剂, 能够解决染料敏化太阳能电池(DSCs)的稳定性问题。但是, QDSCs光电转换效率较低是制约其应用的主要问题。近年来, 通过改变和调控对电极的材料和电子特性提高QDSCs的光电效率的方法受到了广泛关注。本文综述了QDSCs对电极材料的制备方法、微观形貌和晶体结构; 重点分析了金属化合物、复合材料、杂化材料、多元金属硫族化合物、导电聚合物和碳材料对电极对量子点敏化太阳能电池的电荷转移阻抗、光电性能等参数的影响; 并分析影响其电催化活性和电子传输性能的主要因素。最后, 提出通过表面修饰、复合和杂化等方法构筑新型对电极材料, 进而改善和提高QDSCs转换效率和稳定性, 是今后的研究重点和研究方向。     

Graphene supported platinum nanoparticle counter-electrode for enhanced performance of dye-sensitized solar cells

Composites of few layered graphene (G) and platinum (Pt) nanoparticles (NP) with different loadings of Pt were used as counter electrode (CE) in dye-sensitized solar cell (DSSC). NPs were deposited directly on to G using pulsed laser ablation method (PLD). DSSCs formed using the composite CEs show improved performance compared to conventional Pt thin film electrode (Std Pt) and unsupported Pt NPs. Composite with 27% loading of Pt shows 45% higher efficiency (η = 2.9%), greater short circuit current (J(sc) = 6.67 mA cm(-2)), and open circuit voltage (V(oc) = 0.74 V) without any loss of the fill factor (FF = 58%) as compared to the cells fabricated using Std Pt electrodes. Values of η, J(sc) and V(oc) for DSSC using Std Pt CE were 2%, 5.05 mA cm(-2) and 0.68 V, respectively. Electrochemical impedance spectroscopy using I(-)(3)/I(-) redox couple confirm lower values of charge transfer resistance for the composite electrodes, e.g., 2.36 Ω cm(2) as opposed to 7.73 Ω cm(2) of Std Pt. The better catalytic activity of these composite materials is also reflected in the stronger I(-)(3) reduction peaks in cyclic voltammetry scans.     

染料敏化太阳能电池中纯铂对电极的研究进展

作为染料敏化太阳能电池的重要组成部分,对电极的催化性能和价格直接关系到电池的光电转换效率和成本。作为对电极的催化材料,导电聚合物、碳材料和无机化合物等材料虽成本低廉,但其催化性能仍不及金属铂。因此,重点综述了近年来染料敏化太阳能电池纯铂对电极的研究状况,并指出了纯铂对电极中有待解决的问题及今后的发展方向,同时还介绍了染料敏化太阳能电池的工作原理和对电极的作用。     

A decentralised conflict and error detection and prediction model

The objective of this research is to study the performance of a newly developed decentralised conflict and error detection and prediction model (CEDPM) over different networks. In the CEDPM, conflict and error (CE) detection and prediction agents are deployed at each collaborative unit to detect and predict CEs, and exchange information with the support of a CE detection and prediction protocol. Two metrics, detection and prediction time and conflict severity, are defined to evaluate CEDPM and CE propagation, respectively, for linear, divergence, convergence, and parallel coordination networks in which different task dependences exist among collaborative units. Experiment results show that the CEDPM performs significantly better for networks with parallel activities. The conflict severity reflects network complexity and increases as the dependence between collaborative units increases. The findings are useful for the design of emerging prognostics systems-of-systems.     

One‐Step Hydrothermal Tailoring of NiCo2S4 Nanostructures on Conducting Oxide Substrates as an Efficient Counter Electrode in Dye‐Sensitized Solar Cells

A one‐step in situ tailoring of NiCo₂S₄ nanostructures is demonstrated on fluorine‐doped tin oxide (FTO) as Pt‐free counter electrodes (CEs) for dye‐sensitized solar cells (DSSCs) with performance surpassing that of a conventional Pt‐sputtered CE. An interconnected NiCo₂S₄ nanosheet network is successfully constructed on the FTO glass via a hydrothermal method, attributed to the synergistic effect of structure‐directing hexamethylenetetramine and L‐cysteine. A growth mechanism is proposed, and the effects of nanostructures and sulfur atomic percentages on the electrocatalytic performance are discussed in depth. A DSSC with the optimized interconnected NiCo₂S₄ nanosheet CE exhibits higher power conversion efficiency (7.22%) compared to that with a conventional Pt‐sputtered CE (6.87%) due to excellent charge transport properties and enhanced electrocatalytic activity of the NiCo₂S₄ nanostructures. This work showcases the strong potential of nanostructured ternary chalcogenides, which are composed of earth‐abundant elements and prepared through a single‐step hydrothermal process without tedious posttreatments, to reduce the dependence of platinum in DSSCs and other electrochemical devices.     

Edge-oriented MoS<Subscript>2</Subscript> aligned on cellular reduced graphene for enriched dye-sensitized solar cell photovoltaic efficiency

The counter electrode (CE) prominence in dye-sensitized solar cells (DSSCs) is undisputed with research geared towards replacement of Pt with viable substitutes with exceptional conductivity and catalytic activity. Herein, we report the replaceable CE with better performance than that of Pt-based electrode. The chemistry between the graphene oxide and ice templates leads to cellular formation of reduced graphene oxide that achieves greater conductivity to the CE. The simultaneous growth of active edge-oriented MoS₂ on the CE through CVD possesses high reflectivity. High reflective MoS₂ trends to increase the electroactivity by absorbing more photons from the source to dye molecules. Thus, the synergistic effect of two materials was found to showcase better photovoltaic performance of 7.6% against 7.3% for traditional platinum CE.     

Channel estimation assisted by postfixed pseudo-noise sequences padded with zero samples for mobile orthogonal-frequency-division-multiplexing communications

A channel estimation (CE) technique that uses a postfixed pseudo-random sequence padded with zero samples is investigated to extend pseudo-random-postfix orthogonal-frequency-division-multiplexing (PRP-OFDM) communications onto mobile applications. The proposed technique takes advantage of pseudo-noise sequences periodically inserted after each OFDM block within the original guard interval (GI) in conventional zero-padded OFDM (ZP-OFDM) or within the original cyclic prefix (CP) in conventional CP-OFDM. This allows accurate estimation of the channel impulse response. In addition, the proposed technique takes advantage of the null samples padded after the PN sequences for reducing inter-symbol interference occurring with the CEs and with the overlap-add information detection in the conventional PRP-OFDM. The proposed technique successfully applies either (1) a least-squares (LS) CE with assistance from decision-directed data or (2) an approximate LS CE method onto PRP-OFDM-like communications for the purpose of improving CE performance on rapid time-varying channels. Computer simulations in conjunction with statistical analysis assess the performance evaluation of the proposed technique and show that it can achieve lower mean-square estimation errors and lower error probabilities in mobile environments.     

Impact of water-soluble cellulose ethers on polymer-modified mortars

Cellulose ethers (CEs) are employed in many polymer-modified mortars, such as cement renders, masonry mortars, tile adhesives, repair mortars, skim coats, and self-levelling mortars. The addition of CEs to mortars causes the retardation of cement hydration and modifies the microstructural characteristics and the properties of these mortars. The present work attempts to provide a comprehensive review of the current state of knowledge on the effects of CEs and critically identifies gaps in the knowledge. A fundamental scientific understanding concerning the chemistry and hydration of cement, chemical natures, and relevant properties of CEs are discussed. The behaviours and mechanisms of CE adsorption on cement are assessed. The influences of CEs on the kinetics of cement hydration, mechanisms of retardation, and microstructural evolution of the mortars also are reviewed. Finally, the impact of CEs on the properties of fresh and hardened mortars as well as the approaches used to mitigate the negative impacts of CEs are discussed.     

Synthesis of highly active cobalt molybdenum sulfide nanosheets by a one-step hydrothermal method for use in dye-sensitized solar cells

Cobalt molybdenum sulfide (Co_(1 ? x)Mo_xS₂, x = 2/3, 1/2, 1/3) nanocomposites with hierarchical nanosheet structure are prepared on the flexible titanium foils by a facile hydrothermal method and used as the counter electrode (CE) materials for the dye-sensitized solar cells (DSSCs). It is interesting that the first produced MoS₂ nanosheets play an important role as the template for the continuously growing of the Co_(1 ? x)Mo _x S₂ nanosheets. Otherwise, it will grow up into octahedral CoS₂ in the synthesis system without the Mo source. The Co_(1 ? x)Mo _x S₂ CE demonstrates higher catalytic activity for the reduction of triiodide to iodide than that of the MoS_2, and CoS₂ CEs due to the Co_(1 ? x)Mo _x S₂ CE with thinner hierarchical nanosheets offers more catalytic active sites and exhibits additional synergistic effect of the combination of Mo and Co. The DSSC with Co_1/2Mo_1/2S₂ CE achieves a photovoltaic conversion efficiency of 9.16%, which is higher than that of the MoS₂ (8.27%) and CoS₂ (7.18%) CEs and even higher than that of the platinum CE (8.49%) under full sunlight illumination (100 mW cm^?2, AM1.5 G).     

LiFePO<Subscript>4</Subscript>/TiO<Subscript>2</Subscript>/Pt composite film used as effective and robust counter electrode for dye sensitized solar cells

A series of composite films based on LiFePO₄/TiO₂/Pt were synthesized and used as counter electrodes for dye sensitized solar cells (DSSCs). The composites are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET). These analysis results demonstrate that the crystal structure of LiFePO₄ in composite is not changed, and the prepared LiFePO₄/TiO₂/Pt composite films hold a rough surface and porous structure which provide more catalytic activity sites for I₃ ^? reduction and more space for I^?/I₃ ^? diffusion. The DSSC based on LiFePO₄/TiO₂/Pt composite CEs shows a high power conversion efficiency of 6.23% at a low Pt dosage of 2%, comparable to the conventional magnetron sputtering Pt CE (6.31%). The electrochemical analysis reveals that the presented composite CEs have good electrocatalytic activity and low charge transfer resistance. Furthermore, the DSSCs based on LiFePO₄/TiO₂/Pt composite CE exhibit high stability under the continuous tests condition and electrolyte soaking. The results suggest that this LiFePO₄-based composite film could be a perspective electrode for practical application of DSSCs and it maybe provide a potential for further research about photo-charging lithium-ion batteries.     

Device Physics of Dye Solar Cells

Design of new materials for nanostructured dye solar cells (DSC) requires understanding the link between the material properties and cell efficiency. This paper gives an overview of the fundamental and practical aspects of the modeling and characterization of DSCs, and integrates the knowledge into a user‐friendly DSC device model. Starting from basic physical and electrochemical concepts, mathematical expressions for the IV curve and differential resistance of all resistive cell components are derived and their relation to electrochemical impedance spectroscopy (EIS) is explained. The current understanding of the associated physics is discussed in detail and clarified. It is shown how the model parameters can be determined from complete DSCs by current dependent EIS and incident‐photon‐to‐collected‐electron (IPCE) measurements, supplemented by optical characterization, and used to quantify performance losses in DSCs. The paper aims to give a necessary theoretical background and practical guidelines for establishing an effective feedback‐loop for DSC testing and development.     

The possibility of high-temperature heat capacity measurements by differential scanning calorimetry

We have been conducting series of heat capacity measurements by differential scanning calorimetry (DSC) on various latent thermal storage materials such as NaOH-NaNO₃. Our concern is now shifting to higher temperature applications of latent thermal storage: space solar dynamic power systems (solar thermal electric power generation systems in space) and so on. Such applications require storage materials which can be operated above 1000 K. Needs for heat-capacity measurements at higher temperatures are increasing. In the present paper, some results of our heat capacity measurements by DSC at intermediate temperatures are presented. Several items which should be considered in order to realize the heat capacity measurements above 1000 K by DSC are discussed.Paper presented at the Second U.S.-Japan Joint Seminar on Thermophysical Properties, June 23, 1988, Gaithersburg, Maryland, U.S.A.