一维二氧化钛光阳极的制备及在染料敏化太阳能电池中的应用综述

二氧化钛由于具有合适的禁带宽度、良好的光电性能、制作工艺简单等特点,目前广泛应用于染料敏化太阳能电池中。其中,大部分光阳极主要是由纳米颗粒组成,但纳米颗粒不利于电子和空穴的分离及传输、染料敏化太阳能电池的光电转化效率的提升。因此,可采用一维纳米结构光阳极替换纳米颗粒,这有利于提升染料敏化太阳能电池的光电转化效率。一维纳米材料具有较少的晶界,可为电荷提供通道、加速电子的传输,且能有效减少空穴/电子的复合,减少电子与染料的复合,从而提高效率。同时一维二氧化钛其较大的比表面积,不仅有利于染料吸附量增加,而且能有效提高电流密度。综述了几种一维二氧化钛制备方法的最新研究进展,分析了不同制备方法对二氧化钛光阳极的能带结构、光吸收特性、染料吸附量和电子传输过程的影响,介绍了近几年一维二氧化钛在染料敏化太阳能中的应用。最后,对一维二氧化钛在染料敏化太阳能电池中的应用进行了展望。     

敏化TiO2纳米晶多孔膜电极的制备与表征

研究了染料敏化TiO2纳米晶多孔薄膜电极的制备、表征及其光电转换性质，采用溶胶－凝胶法液压涂层制备了TiO2纳米晶多孔薄膜，在无水乙醇中利用薄膜吸附染料2，2′－联吡啶－4，4′－二甲酸合硫氰酸钌进行敏化处理，并利用XPS、AFM、XRD、SEM杉可见－紫外分光光度仪对敏化TiO2纳米晶多孔薄膜进行了表征分析。研究结果表明：薄膜中纳米粒子晶型主要为锐钛矿，粒径在20-30nm，多孔薄膜的孔径在50－200nm；染料敏化多孔薄膜表面吸附了一个单分子层的染料分子，敏化薄膜对可见光有很强的吸收作用，用此薄膜制作的太阳能电池具有较高的光电转化效率，电池效率达到2％，这种薄膜电极改进后可用于制作敏化太阳能电池的光阳极。     

基于介孔TiO_2/石墨烯修饰的TiO_2纳米线光阳极的染料敏化太阳能电池（英文）

本工作制作了基于介孔TiO2/石墨烯修饰的TiO2纳米线光阳极的染料敏化太阳能电池,并进行表征。光阳极结合了介孔TiO2的高染料吸附率,TiO2纳米线的高载流子传导率和石墨烯的高电子收获能力等优点,使器件光电转换效率有了很大的提高。制作出的染料敏化太阳能电池光电转换效率高达7.58%,比纯纳米线制作的电池约提高了1.5倍,在拥有相似一维结构的染料敏化太阳能电池中具有较大优势。     

TiO2介孔薄膜电阻对染料敏化太阳能电池光电转换性能的影响

TiO2介孔薄膜的电阻可能是影响染料敏化太阳能电池光电转化效率的主要因素之一.设计了一种可用于测试TiO2介孔薄膜电阻的方法,研究了2种不同电阻值的TiO2介孔薄膜的电阻变化规律和2种TiO2介孔薄膜组装的染料敏化太阳能电池(DSC)的光电转换性能.结果显示,采用低电阻的TiO2薄膜光电极有利于DSC光电转换效率的提高.     

稀土发光材料在染料敏化太阳能电池中的研究进展

染料敏化太阳能电池(DSSCs)由于工艺简单、价格便宜、转换效率高等优点而备受关注.其中起负载敏化剂以及收集和传输电子作用的光阳极是关系到电池性能的重要部件.介绍了染料敏化太阳能电池的基本结构和工作原理,综述了优化染料敏化太阳能电池结构的研究现状;重点阐述了稀土发光材料改性二氧化钛提高光电转换效率的研究进展;指出稀土发光材料改性二氧化钛光阳极是提高染料电池光电转换效率的有效途径,也是未来的主要发展方向.     

基于介孔TiO2/石墨烯修饰的TiO2纳米线光阳极的染料敏化太阳能电池

本工作制作了基于介孔TiO₂/石墨烯修饰的TiO₂纳米线光阳极的染料敏化太阳能电池,并进行表征。光阳极结合了介孔TiO₂的高染料吸附率,TiO₂纳米线的高载流子传导率和石墨烯的高电子收获能力等优点,使器件光电转换效率有了很大的提高。制作出的染料敏化太阳能电池光电转换效率高达7.58%,比纯纳米线制作的电池约提高了1.5倍,在拥有相似一维结构的染料敏化太阳能电池中具有较大优势。     

TiO2纳米结构在染料敏化太阳电池中的应用

利用纳米结构材料作为光阳极制备的染料敏化太阳电池被称为纳米结构染料敏化太阳电池(NDSSC).一般而言,它由纳米结构金属氧化物半导体的光阳极、染料敏化剂,电解质和对电极等几个部分组成.目前,纳米结构光阳极的研究主要集中在如何优化设计和成功制备各种纳米结构的光阳极材料,以改善NDSSC的光电转换性能.本文着重介绍了各种TiO2纳米结构,例如TiO2晶粒薄膜、TiO2准一维纳米结构、TiO2纳米复合物膜层、TiO2核-壳纳米结构、TiO2量子点敏化结构以及串联电池结构等在NDSSC中的应用,并评论了它们最近的主要研究进展.     

不同染料吸附状态下染料敏化太阳能电池电化学阻抗谱研究

研究了TiO2表面染料的吸附状态不同时,染料敏化太阳能电池(DSC)的光电转换性能,并采用电化学交流阻抗技术(EIS)考察了不同染料吸附状态下DSC中的电子界面复合效应。结果表明,在非饱和吸附染料状态下,通过调整TiO2薄膜表面染料分子吸附量,可以降低界面电荷复合效应,使电子在TiO2薄膜的传输过程中寿命增加,从而提高DSC的填充因子。     

不同染料吸附状态下染料敏化太阳能电池电化学阻抗谱研究

研究了TiO2表面染料的吸附状态不同时,染料敏化太阳能电池(DSC)的光电转换性能,并采用电化学交流阻抗技术(EIS)考察了不同染料吸附状态下DSC中的电子界面复合效应。结果表明,在非饱和吸附染料状态下,通过调整TiO2薄膜表面染料分子吸附量,可以降低界面电荷复合效应,使电子在TiO2薄膜中的传输过程中寿命增加,从而提高DSC的填充因子。     

染料敏化太阳能电池双层结构光阳极研究进展

染料敏化太阳能电池(DSSCs)因为其制备工艺简单、实用化前景好、成本低、转换效率高等优点而受到广泛关注。简要介绍了染料敏化太阳能电池结构和工作原理,并从电解质、染料敏化剂、对电极和光阳极等方面综述了其各组成部分的研究现状。重点以TiO_2/CeO_2复合光阳极为例,阐述了染料敏化太阳能电池光阳极薄膜材料的发展历程,总结了双层结构薄膜材料的光散射效应、上转换性质、比表面积、光响应能力以及电子传输性能对整个电池性能优化的影响,并对未来染料敏化太阳能电池研究方向和前景进行了展望。     

TiO(2) fibers enhance film integrity and photovoltaic performance for electrophoretically deposited dye solar cell photoanodes

Nanoparticulated TiO(2) fibers as one-dimensional long structures were introduced into TiO(2) P25 nanoparticle films using coelectrophoretic deposition. This prevented the usual crack formation occurring in wet coatings, and resulted in less porosity and higher roughness factor of the films that provided more favorable conditions for electron transport. The films used as the photoanode of a dye solar cell (DSC) produced 65% higher photovoltaic efficiency. TiO(2) fibers can be excellent binders in single-step, organic-free electrophoretic deposition of TiO(2) for DSC photoanode.     

Time-resolved indirect nanoplasmonic sensing spectroscopy of dye molecule interactions with dense and mesoporous TiO2 films

Indirect nanoplasmonic sensing (INPS) is an experimental platform exploiting localized surface plasmon resonance (LSPR) detection of processes in nanomaterials, molecular assemblies, and films at the nanoscale. Here we have for the first time applied INPS to study dye molecule adsorption/impregnation of two types of TiO(2) materials: thick (10 μm) mesoporous films of the kind used as photoanode in dye-sensitized solar cells (DSCs), with particle/pore size in the range of 20 nm, and thin (12-70 nm), dense, and flat films. For the thick-film experiments plasmonic Au nanoparticles were placed at the hidden, internal interface between the sensor surface and the mesoporous TiO(2). This approach provides a unique opportunity to selectively follow dye adsorption locally in the hidden interface region inside the material and inspires a generic and new type of nanoplasmonic hidden interface spectroscopy. The specific DSC measurement revealed a time constant of thousands of seconds before the dye impregnation front (the diffusion front) reaches the hidden interface. In contrast, dye adsorption on the dense, thin TiO(2) films exhibited much faster, Langmuir-like monolayer formation kinetics with saturation on a time scale of order 100 s. This new type of INPS measurement provides a powerful tool to measure and optimize dye impregnation kinetics of DSCs and, from a more general point of view, offers a generic experimental platform to measure adsorption/desorption and diffusion phenomena in solid and mesoporous systems and at internal hidden interfaces.     

ZnO nanosheets decorated with CdSe and TiO2 for the architecture of dye-sensitized solar cells

Pure and TiO2- and CdSe-deposited ZnO nanosheets aligned vertically to the surface of ITO (Indium tin oxide) are prepared using electrodeposition, which is used for building blocks of dye sensitized solar cell. A significant improvement in the photovoltaic efficiency can be obtained by depositing TiO2 or CdSe on ZnO. Photoluminescence spectra show that the TiO2 and CdSe nanostructures suppress the recombination of the electron-hole pair of ZnO. We suggest that the interface charge transfer at TiO2-ZnO and CdSe-ZnO should be responsible for the suppression of the electron-hole pair recombination and enhanced solar cell efficiency by TiO2 and CdSe nanostructures.     

Soft chemistry based sponge-like indium tin oxide (ITO) ---- a prospective component of photoanode for solar cell application

Previously we reported the synthesis of novel organic-inorganic composite indium tin oxide (ITO) foam precursor leading to the formation of “sponge-like” ITO by burning away the organics. This newly made sponge-like ITO possesses relatively high electrical conductivity due to phonon confinement with reasonable pore structure and may have potential application as functional materials in semiconducting dye absorbing layer in dye-sensitized solar cell (DSSC) and also as the receptor of electrons injected from the quantum dots (QDs) of organic--inorganic hybrid QD based solar cell. This report is a short review of “sponge-like” ITO described as a lecture note on its future use as an alternative new prospective material for photoanode of solar cell in the domain of sustainable energy.     

Progress in light harvesting and charge injection of dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) based on nanocrystalline semiconductors such as TiO₂ are of great interest as an alternative to the conventional solar cells because of their high performance, low-cost production, and environmental advantages. The DSSCs consist of dye molecule coated wide bandgap semiconductor layer, electrolyte, and transparent conducting oxide (TCO) film. When the DSSCs are exposed to solar light, an incident photon creates a bound electron-hole pair in dye sensitizers. Electrons then flow into the oxide nanoparticle anode due to a difference in the energy levels. On the other hand, holes move to the counter electrode through sequential redox reactions in the electrolyte. Therefore, the cell performance is influenced by parameters such as the morphology and optical properties of nanocrystalline oxide films, the electrochemical characteristics of redox electrolytes, and the photochemical properties of molecular sensitizers. In this article, we review the major components of DSSCs such as the oxide semiconductor film, sensitizing dyes, electrolytes, and TCO and discuss their progress to maximize light harvesting and charge injection efficacy. Their electrical, optical, and chemical properties are well correlated to optimize the light harvesting and charge injection of DSSCs. We have also shown recent efforts to improve the energy conversion efficiency, long term stability, sustainability and affordability by modifying or revolutionizing the components of DSSCs. This includes a prospect on the potential commercialization of DSSCs.     

Metal Oxide Semiconductors for Dye‐ and Quantum‐Dot‐Sensitized Solar Cells

This Review provides a brief summary of the most recent research developments in the synthesis and application of nanostructured metal oxide semiconductors for dye sensitized and quantum dot sensitized solar cells. In these devices, the wide bandgap semiconducting oxide acts as the photoanode, which provides the scaffold for light harvesters (either dye molecules or quantum dots) and electron collection. For this reason, proper tailoring of the optical and electronic properties of the photoanode can significantly boost the functionalities of the operating device. Optimization of the functional properties relies with modulation of the shape and structure of the photoanode, as well as on application of different materials (TiO₂, ZnO, SnO₂) and/or composite systems, which allow fine tuning of electronic band structure. This aspect is critical because it determines exciton and charge dynamics in the photoelectrochemical system and is strictly connected to the photoconversion efficiency of the solar cell. The different strategies for increasing light harvesting and charge collection, inhibiting charge losses due to recombination phenomena, are reviewed thoroughly, highlighting the benefits of proper photoanode preparation, and its crucial role in the development of high efficiency dye sensitized and quantum dot sensitized solar cells.     

Rose bengal-sensitized nanocrystalline ceria photoanode for dye-sensitized solar cell application

For efficient charge injection and transportation, wide bandgap nanostructured metal oxide semiconductors with dye adsorption surface and higher electron mobility are essential properties for photoanode in dye-sensitized solar cells (DSSCs). TiO₂-based DSSCs are well established and so far have demonstrated maximum power conversion efficiency when sensitized with ruthenium-based dyes. Quest for new materials and/or methods is continuous process in scientific investigation, for getting desired comparative results. The conduction band (CB) position of CeO₂ photoanode lies below lowest unoccupied molecular orbital level (LUMO) of rose bengal (RB) dye. Due to this, faster electron transfer from LUMO level of RB dye to CB of CeO₂ is facilitated. Recombination rate of electrons is less in CeO₂ photoanode than that of TiO₂ photoanode. Hence, the lifetime of electrons is more in CeO₂ photoanode. Therefore, we have replaced TiO₂ by ceria (CeO₂) and expensive ruthenium-based dye by a low cost RB dye. In this study, we have synthesized CeO₂ nanoparticles. X-ray diffraction (XRD) analysis confirms the formation of CeO₂ with particle size ～7 nm by Scherrer formula. The bandgap of 2.93 eV is calculated using UV–visible absorption data. The scanning electron microscopy (SEM) images show formation of porous structure of photoanode, which is useful for dye adsorption. The energy dispersive spectroscopy is in confirmation with XRD results, confirming the presence of Ce and O in the ratio of 1:2. UV–visible absorption under diffused reflectance spectra of dye-loaded photoanode confirms the successful dye loading. UV–visible transmission spectrum of CeO₂ photoanode confirms the transparency of photoanode in visible region. The electrochemical impedance spectroscopy analysis confirms less recombination rate and more electron lifetime in RB-sensitized CeO₂ than TiO₂ photoanode. We found that CeO₂ also showed with considerable difference between dark and light DSSCs performance, when loaded with RB dye. The working mechanism of solar cells with fluorine-doped tin oxide (FTO)/CeO₂/RB dye/carbon-coated FTO is discussed. These solar cells show V _OC ～360 mV, J _SC ～0.25 mA cm ^?2 and fill factor ～63% with efficiency of 0.23%. These results are better as compared to costly ruthenium dye-sensitized CeO₂ photoanode.     

Photosensitization of ZnO nanowires with CdSe quantum dots for photovoltaic devices

We combine CdSe semiconductor nanocrystals (or quantum dots) and single-crystal ZnO nanowires to demonstrate a new type of quantum-dot-sensitized solar cell. An array of ZnO nanowires was grown vertically from a fluorine-doped tin oxide conducting substrate. CdSe quantum dots, capped with mercaptopropionic acid, were attached to the surface of the nanowires. When illuminated with visible light, the excited CdSe quantum dots injected electrons across the quantum dot-nanowire interface. The morphology of the nanowires then provided the photoinjected electrons with a direct electrical pathway to the photoanode. With a liquid electrolyte as the hole transport medium, quantum-dot-sensitized nanowire solar cells exhibited short-circuit currents ranging from 1 to 2 mA/cm2 and open-circuit voltages of 0.5-0.6 V when illuminated with 100 mW/cm2 simulated AM1.5 spectrum. Internal quantum efficiencies as high as 50-60% were also obtained.     

ZnO调制改性染料敏化太阳能电池TiO2光阳极研究

采用丝网印刷的方式制备了染料敏化太阳能电池的TiO2薄膜光阳极、TiO2-ZnO复合薄膜光阳极以及TiO2/ZnO双层薄膜光阳极,研究了ZnO对TiO2薄膜光阳极的调制改性作用。研究结果表明分别以醋酸锌和ZnO直接掺杂制备的TiO2-ZnO复合薄膜光阳极同未掺杂的TiO2薄膜光阳极相比,以醋酸锌为原料制备的复合薄膜光阳极使电池转换效率提高了1倍,而由于微米量级的ZnO的粒径大,用其作原料制得的复合薄膜光阳极反而使电池的转换效率有所降低。以醋酸锌为原料制备的TiO2/ZnO双层薄膜光阳极同TiO2薄膜光阳极相比,电池转换效率提高了13倍,通过性能优化后电池的转换效率达到4.7%。