染料敏化太阳能电池Pt/NiP/ITO对电极的制备和性能

在ITO导电玻璃表面化学镀NiP合金薄膜,然后电化学沉积Pt纳米粒子,形成染料敏化太阳能电池Pt/NiP/ITO对电极。优化了化学镀NiP合金的工艺条件;研究了NiP的结构和铂载量对Pt/NiP/ITO电极形貌和催化活性的影响。采用原子力显微镜分析Pt/NiP/ITO电极的表面形貌;采用循环伏安法、电化学交流阻抗法表征其电化学性能;采用单体DSSC的光电流–电压曲线表征其光伏性能。测试结果表明,在ITO基体上化学镀NiP合金,提高了电极的导电性和光反射能力,改善了电极表面Pt粒子的分布,使电池的短路电流密度和光电转化效率分别提高了4%和11%。     

Low temperature preparation of a high performance Pt/SWCNT counter electrode for flexible dye-sensitized solar cells

A platinum/single-wall carbon nanotube (Pt/SWCNT) film was sprayed onto a flexible indium-doped tin oxide coated polyethylene naphthalate (ITO/PEN) substrate to form a counter electrode for use in a flexible dye-sensitized solar cell using a vacuum thermal decomposition method at low temperature (120 °C). The obtained Pt/SWCNT electrode showed good chemical stability and light transmittance and had lower charge transfer resistance and higher electrocatalytic activity for the I₃⁻/I⁻ redox reaction compared to the flexible Pt electrode or a commercial Pt/Ti electrode. The light-to-electric energy conversion efficiency of the flexible DSSC based on the Pt/SWCNT/ITO/PEN counter electrode and the TiO₂/Ti photoanode reached 5.96% under irradiation with a simulated solar light intensity of 100 mW cm⁻². The efficiency was increased by 25.74% compared to the flexible DSSC with an unmodified Pt counter electrode.     

A composite poly(3,3-diethyl-3,4-dihydro-2H-thieno-[3,4-b][1,4]-dioxepine) and Pt film as a counter electrode catalyst in dye-sensitized solar cells

A composite poly(3,3-diethyl-3,4-dihydro-2H-thieno-[3,4-b][1,4]-dioxepine) and platinum (PProDOT-Et₂/Pt) film was prepared for using as a counter electrode (CE) catalyst in a dye-sensitized solar cell (DSSC). Four composite films were prepared by electropolymerization of ProDOT-Et₂ on indium tin oxide (ITO) conducting glass, followed by Pt sputtering for 10, 30, 120, and 720 s. The Pt content in the composite film was verified by energy dispersive X-ray spectroscopy (EDX). The composite films possessed three-dimensional (3D) porous structures, as determined by scanning electron microscopy (SEM). The DSSC with the composite film that was subject to 10 s of Pt deposition (PProDOT-Et₂/Pt-10 s) exhibited the highest solar to electricity conversion efficiency (η) of 6.68%, while the cells with the bare polymer film (PProDOT-Et₂) and Pt that was sputtered for 720 s (s-Pt-720 s) demonstrated efficiencies of 4.76% and 6.43%, respectively. The cell photovoltaic parameters were substantiated through dark current, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) analyses. Incident photon-to-current conversion efficiency (IPCE) curves were used to explain the cell photocurrent behaviors.     

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.     

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.     

A novel hierarchical Pt- and FTO-free counter electrode for dye-sensitized solar cell

A novel hierarchical Pt- and FTO-free counter electrode (CE) for the dye-sensitized solar cell (DSSC) was prepared by spin coating the mixture of TiO₂ nanoparticles and poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) solution onto the glass substrate. Compared with traditional Pt/FTO CE, the cost of the new CE is dramatically reduced by the application of bilayer TiO₂-PEDOT:PSS/PEDOT:PSS film and the glass substrate. The sheet resistance of this composite film is 35 Ω sq⁻¹ and is low enough to be used as an electrode. The surface morphologies of TiO₂-PEDOT:PSS layer and modified PEDOT:PSS layer were characterized by scanning electron microscope, which shows that the former had larger surface areas than the latter. Electrochemical impedance spectra and Tafel polarization curves prove that the catalytic activity of TiO₂-PEDOT:PSS/PEDOT:PSS/glass CE is higher than that of PEDOT:PSS/FTO CE and is similar to Pt/FTO CE''s. This new fabricated device with TiO₂-PEDOT:PSS/PEDOT:PSS/glass CE achieves a high power conversion efficiency (PCE) of 4.67%, reaching 91.39% of DSSC with Pt/FTO CE (5.11%).     

Study of graphene nanoflake as counter electrode in dye sensitized solar cells

Graphene nanoflake (GNF) films have been fabricated on a fluorine doped tin oxide (FTO) glass using a doctor blade method and thermally annealed in air and argon ambient at various temperatures. The GNF/FTO thin films were employed as a counter electrode for dye sensitized solar cells (DSSCs). Results showed the GNF/FTO film could enhance the power conversion efficiency (PCE) of DSSC devices more effectively when annealed in argon ambient rather than in air and at annealing temperatures higher than 380 °C. The PCE enhancement was mainly due to the lowered oxygen concentration in the film and the elevated electrical conductance. A PCE of 6.08% or 88% of that with a Pt counter electrode has been achieved for DSSCs with a GNF counter electrode, suggesting that GNF is a highly potential candidate to replace Pt catalyst.     

A counter electrode of multi-wall carbon nanotubes decorated with tungsten sulfide used in dye-sensitized solar cells

Multi-wall carbon nanotubes decorated with tungsten sulfide (MWCNTs-WS₂) were synthesized by using a hydrothermal method, and used as a low-cost platinum-free counter electrode for dye-sensitized solar cell (DSSC). Cyclic voltammetry and electrochemical impedance spectroscopy characterizations indicate that the counter electrode has a high catalytic activity for the reduction of triiodide to iodide and a low charge transfer resistance at the electrolyte–electrode interface. A DSSC based on this counter electrode achieves a high power conversion efficiency of 6.41% under a simulated solar illumination of 100 mW cm⁻² (AM 1.5). This efficiency is comparable to 6.56% for a DSSC with Pt counter electrode.     

Polyaniline nanofiber/carbon film as flexible counter electrodes in platinum-free dye-sensitized solar cells

Efficient transfer of charges from a counter electrode to an electrolyte is a key process during the operation of dye-sensitized solar cells. Here, we develop a flexible counter electrode by electrochemical deposition of polyaniline nanofibers on graphitized polyimide carbon films for use in a tri-iodide reduction. As determined by the electrochemical impedance spectroscopy, the flexible counter electrode exhibited very low charge transfer resistance and series resistance. These results are due to the high electrocatalytic activity of the polyaniline nanofibers and the high conductivity of the flexible graphitized polyimide film. In combination with a dye-sensitized TiO₂ photoelectrode and electrolyte, the photovoltaic device with the polyaniline counter electrode shows an energy conversion efficiency of 6.85% under 1 sun illumination. Short-term stability tests indicate that the photovoltaic device with the polyaniline counter electrode almost maintains its initial performance.     

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.     

A novel high-performance counter electrode for dye-sensitized solar cells

A novel Pt counter electrode for dye-sensitized solar cells (DSC) was prepared by thermal decomposition of H₂PtCl₆ on NiP-plated glass substrate. The charge-transfer kinetic properties of the platinized NiP-plated glass electrode (Pt/NiP electrode) for triiodide reduction were studied by electrochemical impedance spectroscopy. Pt/NiP electrode has the advantage over the platinized FTO conducting glass electrode (Pt/FTO electrode) in increasing the light reflectance and reducing the sheet resistance leading to improve the light harvest efficiency and the fill factor of the dye-sensitized solar cells effectively. The photon-to-current efficiency and the overall conversion efficiency of DSC using Pt/NiP counter electrode is increased by 20% and 33%, respectively, compared to that of using Pt/FTO counter electrode. Examination of the anodic dissolution and the long-term test on the variation of charge-transfer resistance indicates the good stability of the Pt/NiP electrode in the electrolyte containing iodide/triiodide.     

Improvement of electrochemical and thermal stability of LiFePO4@C batteries by depositing amorphous silicon film

Amorphous silicon (α-Si) films are deposited on LiFePO₄@C electrode by using vacuum thermal evaporation deposition technique and the effect of α-Si film on electrochemical performance of LiFePO₄@C cells is investigated systematically by the charge–discharge testing, cyclic voltammograms and AC impedance spectroscopy, respectively. The results reveal that the present of α-Si film on electrode surface could remarkably improve the electrochemical performance at high charge/discharge rate, especially at elevated temperature. This enhancement may be attributed to the amelioration of the electrochemical dynamics on the electrode/electrolyte interface resulting from the beneficial effects of α-Si film, which might significantly suppress the rise of both of the surface film resistance and charge transfer resistance.     

染料敏化太阳能电池低铂对电极的制备和性能

采用热分解法制备Pt/ITO电极用于染料敏化太阳能电池（DSSC）。研究了热分解法相关工艺参数,包括烧结条件、不同的黏合剂以及黏合剂用量等。采用扫描电镜（SEM）分析了所制备的Pt/ITO对电极的表面形貌,通过循环伏安法（CV）对其电化学性能进行了表征。结果表明,采用适量羧甲基纤维素钠作为黏合剂,经5次烧结铂载量达到0235 mg/cm2时,Pt/ITO电极即对I^-/I^-₃（I₂）电对的氧化还原过程表现出良好的电催化活性。单体DSSC测试研究表明,所制备的低铂对电极的光电转换效率已接近铂片对电极的水平。     

Fabrication of high performance Pt counter electrodes on conductive plastic substrate for flexible dye-sensitized solar cells

Pt counter electrodes (CEs) with different platinum loading have been prepared using chemical reduced method on flexible indium-doped tin oxide coated polyethylene naphthalate (ITO-PEN) for dye-sensitized solar cells (DSSCs). H₂PtCl₆·6H₂O terpineol solutions were screen printed on the transparent ITO-PEN substrates. After drying, H₂PtCl₆ was reduced by treating it in NaBH₄ solution followed by the hydrothermal treatment at 100 °C. The obtained Pt CEs with different Pt-loading (2.4-7.7 μg/cm²) were characterized by SEM, XPS, electrochemical impedance and transmission spectrum measurement. The Pt CEs show high catalytic activity, low charge transfer resistance (0.26-1.38 Ω cm²) and good light transmittance (about 70% at 400-800 nm). The light-to-electricity conversion efficiency of the flexible DSSC fabricated with the prepared Pt CE and the TiO₂ photoanode prepared on Ti substrate by screen printing technique attains 5.41% under the simulated AM 1.5 sunlight, which is almost same as that based on the thermal decomposited Pt CE on FTO-glass. Compared with other methods to prepare Pt CEs, chemical reduced method is simple and suitable for flexible polymer substrates and the large scale preparation of DSSCs.     

底电极原位退火与沉积温度对PZT薄膜性能影响研究

采用磁控溅射工艺,在Pt/Ti底电极上沉积锆钛酸铅(PZT)薄膜,研究了原位退火温度与底电极沉积温度对溅射PZT薄膜结晶取向、微观结构、介电性能、铁电性能及疲劳性能的影响。X射线衍射(XRD)和扫描电子显微镜(SEM)分析结果表明,随着电极沉积温度升高,Pt晶粒尺寸增大,随着退火温度升高,PZT薄膜致密性变差。对室温制备的Pt/Ti底电极进行200 ℃原位退火30 min后,易于促进PZT薄膜沿(100)择优取向,而高温制备或经高温退火处理的Pt/Ti底电极更有利于PZT薄膜的(111)晶向生长。电学性能分析表明,室温制备的Pt/Ti底电极在经200 ℃原位退火30 min后,其PZT薄膜介电性能最优,同时展现较高的剩余极化强度和最小的矫顽场强,经历10⁸次极化翻转后,初始极化下降仅为11％。     

Photovoltaic Properties and Negative Capacitance Spectroscopy of PCBM:P3HT/FTO Nanostructured Counter Electrode for TiO2-Based DSSC

Nano-clusters blind films of phenyl C61-butyric acid methyl ester (PCBM) and poly(3-hexylthiophene) (P3HT) were deposited on fluorine doped tin-oxide (FTO) substrate by spin coating and applied as counter electrodes instead of platinum for a new FTO/TiO₂?+?K30 dye-sensitized solar cell. The photovoltaic parameters of the fabricated solar cell; open circuit voltage, short circuit current, output power and fill factor, were studied under various light intensities in the range 20:110?mW?cm^?2. An impedance spectroscopy study was also performed in a wide frequency range (5?kHz–1?MHz) to study the electron transport properties of the solar cells. The capacitance–voltage of the prepared DSSC is characterized by two parts: positive values of capacitance at low frequency range, f?≤?100?kHz and negative capacitance i.e., an inductive behavior, in higher frequency range f?≥ 300 kHz Conducting polymer electrode based on PCBM:P3HT/FTO can be used as a counter electrode in a DSSC.     

Low-Cost Flexible Nano-Sulfide/Carbon Composite Counter Electrode for Quantum-Dot-Sensitized Solar Cell

Cu₂S nanocrystal particles were in situ deposited on graphite paper to prepare nano-sulfide/carbon composite counter electrode for CdS/CdSe quantum-dot-sensitized solar cell (QDSC). By optimization of deposition time, photovoltaic conversion efficiency up to 3.08% was obtained. In the meantime, this composite counter electrode was superior to the commonly used Pt, Au and carbon counter electrodes. Electrochemical impedance spectra further confirmed that low charge transfer resistance at counter electrode/electrolyte interface was responsible for this, implied the potential application of this composite counter electrode in high-efficiency QDSC.     

Polyethylene glycol-modified poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) counter electrodes for dye-sensitized solar cell

Poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) counter electrodes, doped with polyethylene glycol (PEG) and acetylene black as binding and conductivity promoting agent, were prepared by a simple mixing method for dye-sensitized solar cell. The electrochemical properties of the electrodes were characterized by cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and Tafel polarization curves. Using PEG dopant, the electrocatalytic activity of PEDOT:PSS electrode was much improved, and further improved by adding a small amount of conducting acetylene black (0.2 wt%). The DSSC cells, using the PEDOT:PSS electrode with PEG (5 wt%) dopant and the composite electrode with PEG (5 wt%)/acetylene black, exhibited an energy conversion efficiency of 3.57 and 4.39 %, comparable with 4.50 % of the commonly used Pt electrode under the same experimental conditions. These results demonstrate that PEG-modified PEDOT:PSS counter electrode is promising to replace the expensive Pt for low cost DSSC, especially to meet the large-scale fabrication demands.     

柔性染料敏化太阳能电池材料制备工艺参数的优化

采用水热法制备TiO2纳米浆,与P25粒子和TiO2散射大粒子混合制成级配浆料。将所得的浆料涂敷在铟掺杂氧化锡-聚苯二甲酸乙二醇酯导电聚合物基板上,并在120～150℃进行热处理制成光阳极薄膜。利用溅射法制备Pt对电极,将其组装成柔性的染料敏化太阳能电池(dye-sensitized solar cell,DSC)。研究了对电极溅射时间、TiO2薄膜热处理温度、膜厚以及级配浆料中的酸添加量对电池光电性能的影响。结果表明:当对电极Pt溅射时间为30s,TiO2薄膜热处理温度为150℃,膜厚为10.5μm,浆料添加0.05mol/LHNO3时,柔性DSC的光电性能最好,光电转换效率可达4.05%。     

Sheet resistance dependence of fluorine-doped tin oxide films for high-performance electrochromic devices

In the present study, we fabricated fluorine-doped tin oxide (FTO) films with different sheet resistances (~10?Ω/□, ~6?Ω/□, and ~3?Ω/□) prepared through the adjustment of deposition time during the horizontal ultrasonic spray pyrolysis deposition (HUSPD) and investigated the effect of electrochromic (EC) performances with different sheet resistances of the FTO films used as transparent conducting electrodes. The results demonstrated that, owing to the increased electrochemical activity, the decrease of sheet resistance accelerated switching speeds of the EC devices. However, for the coloration efficiency (CE), the FTO films with the optimum sheet resistance of ~6?Ω/□ exhibited the highest value as compared to the other samples. The improvement of the CE value can be mainly attributed to high transmittance modulation by the uniform surface morphology of the FTO films to reduce interfacial light-scattering between the WO₃ films and FTO films. Therefore, our results provide a valuable insight into the improvement of the performance of the EC devices using the optimum sheet resistance (~6?Ω/□) of the FTO films.