基于p型光电极的染料敏化太阳能电池研究进展

基于p型光电极的染料敏化太阳能电池是一种受到广泛关注的新型太阳能电池。根据电池的结构不同可以将其分为p型和p-n叠层型染料敏化太阳能电池。其中p-n型叠层染料敏化太阳能电池的理论光电效率可以达到43%,高于传统的基于n型TiO_2光阳极的染料敏化太阳能电池理论效率(30%),引起了科学界的高度关注。本文将总结基于p型光电极染料敏化太阳能电池(p型和p-n型叠层器件)的研究成果,重点介绍用于p型和p-n型叠层染料敏化太阳能电池的电极材料,染料及电解质的研究进展;同时总结目前该类电池发展中亟需解决的问题以及进一步提高器件效率的途径。     

基于p型光电极的染料敏化太阳能电池研究进展

基于p型光电极的染料敏化太阳能电池是一种受到广泛关注的新型太阳能电池。根据电池的结构不同可以将其分为p型和p-n叠层型染料敏化太阳能电池。其中p-n型叠层染料敏化太阳能电池的理论光电效率可以达到43%,高于传统的基于n型TiO₂光阳极的染料敏化太阳能电池理论效率（30%）,引起了科学界的高度关注。本文将总结基于p型光电极染料敏化太阳能电池（p型和p-n型叠层器件）的研究成果,重点介绍用于p型和p-n型叠层染料敏化太阳能电池的电极材料,染料及电解质的研究进展;同时总结目前该类电池发展中亟需解决的问题以及进一步提高器件效率的途径。     

染料敏化太阳能电池对电极

对电极是染料敏化太阳能电池的重要组成部分,改进对电极是提高其能量转换效率及降低成本的有效手段之一.本文重点综述了2008年以来染料敏化太阳能电池对电极的研究成果,详细介绍了各类对电极包括金属Pt、Au、Ni,纳米炭材料和导电聚合物等对电极的优点和制备工艺.Pt对电极性能最好,但是高成本限制了它在染料敏化太阳能电池产业化中的应用;新型的价格低廉、活性较高的纳米炭材料和导电聚合物及其复合材料等对电极在染料敏化太阳能电池的研究中逐渐引起人们的重视.     

有机染料敏化纳米晶太阳能电池

本文综述了有机染料敏化纳米晶太阳能电池的研究现状,简要介绍了有机染料敏化纳米晶太阳能电池的结构和工作原理以及氧化物电极、对电极和电解质的设计思路和制备情况。重点介绍了有机染料的研究现状,包括香豆素类染料、多烯类染料、噻吩类染料、天然染料、半花菁类染料、卟啉类染料、三苯胺类染料、苝类染料等。同时讨论了若干影响有机染料敏化太阳能电池性能的因素,提出了提高光电转换效率的设想与对策,对未来的发展进行了展望。     

基于不同取代基的噻吩-三苯胺染料敏化剂的合成与光伏性能

本文合成了含3种不同取代基的噻吩-三苯胺染料敏化剂(H1,H2和H3),并将其应用于二氧化钛纳米晶染料敏化太阳能电池.系统地研究了3种染料的光物理、电化学和光伏性能.基于H1的染料敏化太阳能电池获得了9.10%的光电转换效率(Voc=0.72V,Jsc=18.03mAcm-2,FF=0.70).     

准固态染料敏化太阳能电池中电解质体系的研究进展

染料敏化太阳能电池(Dye Sensitized Solar Cells)是新一代将光能转化为电能的重要能源转换装置。它具有低廉的材料和器件制作成本、较高的光电转换效率以及电池制作过程简单等诸多优点,拥有广阔的应用空间和巨大的潜在商业价值,因而吸引了广泛的研究关注。染料敏化太阳能电池主要由染料敏化的光阳极、电解质和对电极三个部分组成。其中,电解质作为染料敏化太阳能电池的重要组成部分,其对离子的传导和扩散,以及促进染料再生的能力极大地影响着染料敏化太阳能电池的电荷传输和光电性能。本文聚焦于染料敏化太阳能电池准固态电解质体系,主要从聚合物凝胶电解质、有机小分子凝胶电解质和无机纳米粒子凝胶电解质三大方面综述讨论了该研究领域当前最新研究进展,并对其未来研究趋势进行了展望。     

染料敏化纳米太阳能电池

本文介绍了染料敏化纳米太阳能电池的结构和原理 ,对纳米TiO2 膜、敏化染料、空穴传输材料的研究进展进行了综述 .     

水热法可控合成二氧化钛纳米晶及其在染料敏化太阳能电池中的应用

本文报道了水热法可控合成二氧化钛纳米晶及其在染料敏化太阳能电池中的应用.选择合适的有机碱胶化剂,能很好地控制二氧化钛纳米晶的生长,形成不同形貌和粒径的锐钛矿型二氧化钛纳米晶颗粒.染料敏化太阳能电池光电性能测试结果表明,以四乙基氢氧化铵为胶化剂合成的边长为8～13nm的正方形二氧化钛纳米晶构成的光阳极光电性能优于以四丁基氢氧化铵为胶化剂合成的边长为7～10nm的正方形二氧化钛纳米晶以及长18～35nm,宽10～18nm的长方形二氧化钛纳米晶构成的光阳极.用较高浓度的四甲基氢氧化铵胶化剂能合成球形或椭球形亚微米级二氧化钛颗粒,以其为散射中心在光阳极中构建散射层,染料敏化太阳能电池的光电转换效率能由6.77%提高到8.18%.     

染料敏化纳米晶体TiO_2太阳能电池的对电极结构

通过对染料敏化纳米晶体TiO2太阳能电池的对电极的结构进行改进,设计了一种可大容量储存电解质和补充电解质的新型对电极结构.当染料敏化纳米晶体TiO2太阳能电池因液态电解质挥发泄漏而失效时,可以对其进行液态电解质的及时补充,从而使失效的染料敏化纳米晶体TiO2太阳能电池重新恢复工作.该新型对电极结构为解决染料敏化纳米晶体TiO2太阳能电池由于液态电解质泄漏导致的寿命降低问题提供了一种新的解决方法.     

染料敏化太阳电池用电解质的研究进展

染料敏化太阳能电池(DSCs)由于其清洁廉价的优点而受到广泛关注。经过多年的研究,目前电池的转换效率已十分可观。电解质在染料敏化太阳能电池中起到桥梁作用,担负着还原染料、输运载流子完成电池内部循环的作用。电解质根据物理状态不同将其分为液态电解质、准固态电解质和固态电解质。介绍了这三种不同电解质的性能、各自的优点及存在问题,并对染料敏化太阳能电池中电解质在国内外研究发展现状进行了综述。     

Carbon nanotubes as photoprotectors of organic dyes: reversible photoreaction instead of permanent photo-oxidation

In this paper we report that single-walled carbon nanotubes (SWNTs) can protect surface adsorbed Rhodamine B (RhB) molecules from permanent photo-oxidation via a reversible reaction. Upon strong light irradiation at 514 nm, the SWNT-adsorbed RhB molecules were switched to a non-fluorescent form, which looked like ordinary bleaching behavior. However, after staying without light for several hours the non-fluorescent dye species turned back to the original fluorescent form. This on/off switching can be considered as a reversible photobleaching process of the dye molecules. Other irreversible photochemical pathways of RhB were strongly prohibited due to the presence of SWNTs, providing the dye molecules with a high resistance against permanent photodegradation. By determining the maximum number of reconvertable RhB molecules per unit length of the nanotubes, we have further proved that this effect only works for the first layer of adsorbed dye molecules on the SWNT surfaces.     

Aggregation of rhodamine 3B adsorbed in Wyoming Montmorillonite aqueous suspensions

The adsorption of Rhodamine 3B (R3B) molecules in Wyoming Montmorillonite (Mont) particles suspended in water was studied by electronic absorption spectroscopy. Several adsorbed R3B species in the Mont tactoids were characterized from the observed changes in the absorption spectra by increasing the relative dye/clay concentration and the stirring time of the samples. R3B molecules can be adsorbed as monomeric units both in the water/clay interface and in the interlayer space, and head-to-tail R3B dimers and trimers were present in the external surface of Mont. The formation of internally adsorbed R3B monomers by the migration of the externally adsorbed species to the interlayer space leads to the deaggregation of the dye molecules in the external surface.     

Dye Bonding to TiO(2): In Situ Attenuated Total Reflection Infrared Spectroscopy Study, Simulations, and Correlation with Dye-Sensitized Solar Cell Characteristics

Processing dye-sensitized solar cells gains more and more importance as interest in industrial applications grows daily. For large-scale processing and optimizing manufacturing in terms of environmental acceptability as well as time and material saving, a detailed knowledge of certain process steps is crucial. In this paper we concentrate on the sensitizing step of production, i.e., the anchoring of the dye molecules onto the TiO(2) semiconductor. A vacuum-tight attentuated total reflection infrared (ATR-IR) flow-through cell was developed, thus allowing measurements using a vacuum spectrometer to monitor infiltration of dye molecules into the porous TiO(2) film in situ at high sensitivity. In particular, the influence of the anchor and backbone of perylene dye molecules as well as the influence of solvents on the adsorption process was investigated. The experiments clearly show that an anhydride group reacts much slower than an acid group. A significantly lower amount of anhydride dye can be adsorbed on the films. Ex situ transmission experiments furthermore indicate that the availability of OH groups on the TiO(2) surface may limit dye adsorption. Also the backbone and base frame of the dye can influence the adsorption time drastically. Electrical cell characteristics correlate with the amount of adsorbed dye molecules determined by in situ ATR-IR measurements. The latter is also sensitive toward the diffusion of the dye through the porous layer. To gain a deeper understanding of the interplay between diffusion and adsorption, simulations were performed that allowed us to extract diffusion and adsorption constants. Again it was demonstrated that the anchoring group has a strong effect on the adsorption rate. The influence of the solvent was also studied, and it was found that both adsorption and desorption are affected by the solvent. Protic polar solvents are able to remove bound dye molecules, which is a possible pathway of cell degradation. Most importantly, the analysis shows the potential of this approach for the evaluation of molecules or additives concerning their characteristics important for cell processing.     

Adsorption study of cationic dyes having a trimethylammonium anchor group on hectorite using electrooptic and spectroscopic methods

Clay minerals are natural or synthetic material of colloidal dimensions. Due to the sheetlike structure clay minerals offer a huge specific surface area and hence optimal properties for modification through adsorption. The current work studies the adsorption of five cationic dyes on the synthetic clay mineral hectorite. All dyes have a trimethylammonium anchoring group in common. The adsorbed dye molecules are characterized by means of pulsed electric linear dichroism and UV-VIS spectroscopy. With increasing dye loading a continuous shift in the absorption spectra is observed. But there is no occurrence of a new absorption band. Therefore we conclude that the dyes preferentially adsorb as amorphous aggregates on the clay surface. At low dye loadings the dye molecules lie flat on the clay mineral surface. Increasing dye concentration leads to a continuous increase in average tilt angle. However the orientation of the dye molecules is very sensitive to functional groups. The introduction of a nitro group to a particular dye increases significantly the tendency to lie flat on the surface whereas the introduction of a methoxy group at the same position has the opposite effect.     

The influence of noncovalent interactions in metal‐free organic dye molecules to augment the efficiency of dye sensitized solar cells: A computational study

The efficiency of dye sensitized solar cells (DSSCs) can be enhanced with achieving better planarity of metal‐free organic dye molecules and thinning of their aggregation on the semiconductor surface. We report that the subtle noncovalent N^…S interaction between the substituted phosphazene group and thiophene spacer unit in dye molecule which induces the desired planarity and avoid aggregation of such molecules on the TiO₂ surface using DFT calculations. DFT results show that phosphazene group increases the maximum absorption wavelength (λ_max), driving force for electrons injection (ΔG_injection), singlet excited state lifetime (τ), dipole moments (μ_normal), and number of electrons transferred from dye to TiO₂ surface (Δq), which are known to augment the efficiency of DSSCs. Further, the lower ΔG_regeneration value of phosphazene containing dyes (e.g., –.37 eV, dye 2 ) than the reported dyes (e.g., –.81 eV, dye 1 ) indicate the faster electron injection rate from the former dye to the semiconductor TiO₂. The role of phosphazene group to prevent the aggregation of dye molecules on the TiO₂ anatase surface was also examined with GGA‐PBE/DNP level of theory. The calculated results suggest that the dye molecules on 1 ‐(TiO₂)₃₈ and 2 ‐(TiO₂)₃₈ anatase clusters avoids the aggregation due to the steric congestion induced by phosphazene group. This work reports to accomplish dual properties with subtle noncovalent interactions in dye molecules to augment the efficiency in DSSCs.     

Design of high‐performance chlorine type dyes for dye‐sensitized solar cells

Intrinsic defect of electronic structure for the chlorine‐type porphyrin 1, which was synthesized for use in dye‐sensitized solar cell (DSSC), is found by theoretical calculation including density functional method (DFT), time‐dependent DFT, and C+/C? function. It is believed that the limited cell performance obtained by using dye 1 as the sensitizer is due to the existence of this electronic defect. To avoid this defect, a series of novel molecules with electron deficient π bridge were designed. The subsequent theoretical calculation indicated that the electron deficient π bridge in the newly designed molecule is quite effective in offsetting the electronic defect observed for dye 1. The parameters for the designed molecules closely associated with open‐circuit voltage and short‐circuit current density including dipole moment of dye vertical to the surface of semiconductor and light‐harvesting efficiency were then evaluated. By comparing these parameters of designed dyes with those of dye 1, we can predict that the DSSC based on dye 4 (2, 6‐cyan benzoic acid as anchoring group) should possess enhanced performance, which would be a valuable theoretical guidance for the practical work. © 2013 Wiley Periodicals, Inc.     

Colouring mechanism of dyed KDP crystal by quantum chemistry

Dye adsorption mechanism, in particular, colouring mechanism of KDP (KH₂PO₄) crystal was investigated by quantum chemistry in this study. Phenomena, such as different preferentially coloured faces of KDP when co-crystallised with different dyes, are explained by the minimum and maximum values of electrostatic potential (ESP). Furthermore, it is found that the ESP distribution of a dye molecule may not necessarily be the single mechanism affecting the dye adsorption in a crystal structure; and that the degree of protonation, crystal surface condition, steric exclusion of dye and the orientation of dye molecules situating on the crystal surface may as well be important factors for the dye adsorption.     

Luminescent properties of dye-PMMA composite nanospheres

The luminescent properties of two types of dye-poly(methyl methacrylate) (PMMA) composite nanospheres were discussed and compared. Dye molecules (Ru(bpy)(3)Cl(2)) were combined with PMMA nanospheres in two strategies: embedding dye molecules during PMMA nanosphere formation (Em-PMMA NPs) and adsorbing dye molecules onto the surface of the produced PMMA nanospheres (Ad-PMMA NPs). It has been proved that the electrostatic interaction dominated the load of Ru(bpy)(3)(2+) on the PMMA matrix. The luminescence intensity of the Em-PMMA NPs was much higher than that of the Ad-PMMA NPs under same dye concentration due to different dye load distribution in two types of dye-PMMA composite nanospheres. Luminescence lifetime measurement of Ru(bpy)(3)(2+) in the Em-PMMA NPs (containing 2.20 × 10(3) Ru(bpy)(3)(2+) molecules per NP) indicates that ～60% of dye molecules loaded in inside of the PMMA matrix and ～40% located close to/on the surface of NPs. For the Ad-PMMA NPs containing same amount of dye as Em-PMMA Nps, most of dye molecules (～84%) were on the surface of NPs and only ～16% of them penetrated into the PMMA matrix. The luminescence of the Em-PMMA NPs had nearly seven fold enhancement and the excited-state lifetime had nearly five fold extension relative to a dye aqueous solution. The mechanism of luminescence enhancement was studied. The results indicate that the larger viscosity and weaker polarity of a PMMA matrix led to the luminescence enhancement of Ru(bpy)(3)(2+). These luminescent PMMA nanospheres with high stability, long lifetime and high brightness hold great the potential for being a novel biological label.     

Inverted Opal Fluorescent Film Chemosensor for the Detection of Explosive Nitroaromatic Vapors through Fluorescence Resonance Energy Transfer

This paper reports an inverted opal fluorescence chemosensor for the ultrasensitive detection of explosive nitroaromatic vapors through resonance‐energy‐transfer‐amplified fluorescence quenching. The inverted opal silica film with amino ligands was first fabricated by the acid–base interaction between 3‐aminopropyltriethoxysilane and surface sulfonic groups on polystyrene microsphere templates. The fluorescent dye was then chemically anchored onto the interconnected porous surface to form a hybrid monolayer of amino ligands and dye molecules. The amino ligands can efficiently capture vapor molecules of nitroaromatics such as 2,4,6‐trinitrotoluene (TNT) through the charge‐transfer complexing interaction between electron‐rich amino ligands and electron‐deficient aromatic rings. Meanwhile, the resultant TNT–amine complexes can strongly suppress the fluorescence emission of the chosen dye by the fluorescent resonance energy transfer (FRET) from the dye donor to the irradiative TNT–amino acceptor through intermolecular polar–polar resonance at spatial proximity. The quenching response of the highly ordered porous films with TNT is greatly amplified by at least 10‐fold that of the amorphous silica films, due to the interconnected porous structure and large surface‐to‐volume ratio. The inverted opal film with a stable fluorescence brightness and strong analyte affinity has lead to an ultrasensitive detection of several ppb of TNT vapor in air.