Influence of Modification of Counter Electrode on PhotoelectricProperties of Dye-sensitized TiO_2 Solar Cells

A dye-sensitized nanocrystalline TiO 2 solar cell(DYSC) was assembled, of which counter electrode was modified already by platinum, nickel and carbon. It was found that the DYSC had better photoelectric performance when the electrode was modified by platinum than by nickel and carbon. The influence of the incidence light wavelength on the incidence monochromatic photoelectric conversion efficiency(IPCE) was investigated. The result shows that the IPCE mainly depends on the short-circuit current density(I SC) of a DYSC, and the IPCE reaches 48.32% under the irradiation with the wavelength of 560 nm when the counter electrode of a DYSC was modified by platinum. The influence of incident light intensity on the photoelectric properties of a DYSC was also investigated. It was found that the I SC and open-circuit voltage(V OC) increased and the fill factor(f f) of the DYSC decreased with the increase of the incident light intensity.

Review on development of electrolytes for dye-sensitized solar cells

Since the prototype of a dye-sensitized solar cell(DSSC)was reported in 1991 by M. Gratzel,it has aroused intensive interest over the past decade due to its low cost and simple preparation procedure.The typical cell consists of a dye-coated mesoporous nanocrystalline TiO_2 film sandwiched between two transparent electroldes.A liquid electrolyte,traditionally containing the trioidide/iodide redox couple,fills the pores of the mesoporous nanocrystalline TiO_2 film and contacts the nanoparticles.Photoexcite...

A highly efficient electric additive for enhancing photovoltaic performance of dye-sensitized solar cells

N-cetylpyridinium iodide (N-CPI) as a new electric additive for enhancing photovoltaic performance of the dye-sensitized solar cell (DSSC) was studied.It showed high efficiency for enhancing both the open-circuit voltage and the short-circuit current density of DSSC when the suitable amount of N-CPI as 0.02 M was added in liquid electrolyte.The energy conversion effi- ciency of DSSC increased from 4.429% to 6.535%,with 47.55% enhancement.Therefore,it is a highly efficient electric addi- tive for DSSC.The intrinsic reason is owing to the special molecular structure of N-CPI,which contains two different polarity groups.As a surfactant,N-CPI could form ordered arrangement in liquid electrolyte,which affects the diffusing ability and the redox reaction of I-/I3-,and further affects the photovoltaic performance of DSSC.

Significant Enhancement in Photovoltaic Performances for C217-based Dye Sensitizers via Introducing Electron-withdrawing Substituents: a Theoretical Study

Dye-sensitized solar cells(DSSCs) are one of the most promising photovoltaic technologies, and the development of efficient dye sensitizers, especially inexpensive metal-free organic dyes, is always crucial for fabricating new DSSC devices. In this paper, a series of novel metal-free dyes with the D-A-π-A structure were designed by introducing electron-withdrawing substituents into the C217 molecular skeleton, and then their photovoltaic parameters were predicted by means of density functional theory(DFT) and time-dependent DFT(TD-DFT) calculations in combination with the Marcus charge transfer model. Our results showed that compared with C217, the introduction of trifluoromethyl(-CF3), cyano(-CN), and nitryl(-NO2) can efficiently narrow the HOMO-LUMO gap, and remarkably enhance the dye’s sunlight harvesting. With the(TiO2)38 cluster model, the photoelectric conversion efficiency(PCE) for the C217 dye was predicted to be up to 9.82%, which is in good agreement with the measured value(9.6%~9.8%), suggesting that our scheme used in this paper is reliable. Based on the same method, the PCE of most designed dyes was estimated to exceed over 10%, denoting that the molecular design strategy recommended by us in this work is reasonable. Especially, the PCE values of the dye 1, 4, and 6 were found to be as high as 14.75%, 16.02% and 15.75% respectively, suggesting that these three dyes are potential candidates as efficient sensitizers, and are worth further experimental study.

2D-π-A Type Organic Dyes Based on N,N-Dimethylaryl Amine and Rhodamine-3-acetic Acid for Dye-sensitized Solar Cells

Three organic dyes XS17--19 based on N,N-dimethylaryl amine and rhodamine-3-acetic acid moieties are designed and synthesized. These dyes were applied into nanocrystalline TiOa dye-sensitized solar cells through standard operations, showing strong absorption bands at around 320--650 rim, and exhibiting broad IPCE responses. Cell based on XS17 gave a Jsc of 3.7 mA/cm2, an open circuit voltage of 550 mV, and a fill factor of 0.68, corresponding to an overall conversion efficiency of 1.4%. The low overall conversion efficiency is due to the modest IPCE and Voc values, which mainly stem from the acceptor of rhodanine-3-acetic acid.

Dye-sensitized solar cells based on functionalized truxene structure

Three new metal-free organic dyes （TX1, TX2 and TX3） based on truxene core structure, with triphenylamine as the electron donor, thiophene as the n spacers, and cyanoacetic acid or rhodanine-3- acetic acid as the electron acceptor are designed and synthesized. Their UV-vis absorption spectra, electrochemical and photovoltaic properties were investigated. The cyanoacrylic acid is verified to be a better acceptor unit （meanwhile the anchoring group） compared to the rhodanine-3-acetic acid. And also, two anchoring groups in TX2 could provide stronger adsorption ability on the TiO2 surface. In addition, the EIS results indicate a slower charge recombination processes for TX2. As a result, dye TX2 bearing two cyanoacetic acid outperforms the other two dyes, exhibiting the photo-conversion efficiency of 2.64%, with Jsc = 5.09 mAcm^-2, Voc = 729 mV, FF = 71.1.

Integration of buildings with third-generation photovoltaic solar cells: a review

Clean-energy technologies have been welcomed due to environmental concerns and high fossil-fuel costs.Today,photovoltaic(PV)cells are among the most well-known technologies that are used today to integrate with buildings.Particularly,these cells have attracted the attention of researchers and designers,combined with the windows and facades of buildings,as solar cells that are in a typical window or facade of a building can reduce the demand for urban electricity by generating clean electricity.Among the four generations that have been industrialized in the development of solar cells,the third generation,including dye-sensitized solar cells(DSSCs)and perovskite,is used more in combination with the facades and windows of buildings.Due to the characteristics of these cells,the study of transparency,colour effect and their impact on energy consumption is considerable.Up to now,case studies have highlighted the features mentioned in the building combination.Therefore,this paper aims to provide constructive information about the practical and functional features as well as the limitations of this technology,which can be used as a reference for researchers and designers.

Recent research progress for upconversion assisted dye-sensitized solar cells

Upconversion(UC)technology makes it possible to harvest infrared(IR)light from the sun and has increasingly been employed in recent years to improve the efficiency of solar cells.The progress in the area concerns both research on fundamental principles and processes of UC and technologies of device fabrication.Significant increase of important solar cell parameters,like short-circuit photocurrent density and open-circuit photovoltage as well as the total photon-to-current efficiency,has been accomplished.We here review the research published during the last few years in the area,in particular we consider the two most cherished techniques,namely the incorporation of upconverting nanophosphors directly into the photoanodes of the solar cells and the introduction of plasmonic metal nanoparticles co-existing with the UC particles.Other ways to achieve strong field enhancement,and the use of the non-linear nature of UC,is to apply microlenses,with or without assisting plasmonic excitation.Further enhanced UC action has been demonstrated by broad band and effective harvesting by organic IR antennas,with subsequent mediation by an intermediate nanoshell of the energy into the upconverting core.Codoping,nanohybrid and layer-by-layer technologies involving upconverting particles as well as the use of upconverting nanoparticles in hole-transport and electrolyte layers,tested in recent works,are also reviewed.While most of these technologies employ upconverting rare earth metals for sequential photon absorption,the main alternative technique,namely triplet-triplet annihilation UC using organic materials,is also reviewed.It is our belief that all these approaches will be further much researched in the near future,with potentially great impact on solar cell technology.

Ethoxy-substituted Oligo-phenylenevinylene-Bridged Organic Dyes for Efficient Dye-Sensitized Solar Cells

Organic dyes with ethoxy-substituted oligo-phenylenevinylene as chromophores were synthesized for dye-sensitized solar cells （DSSCs）, and the detailed relationships between the dye structures, photophysical properties, electrochemical properties, and performances of DSSCs were described. The dye S3O showed broad IPCE spectra in the spectral range of 350--750 nm, and the dye S1P showed solar energy-to-electricity conversion efficiency （1/） of up to 4.23% under AM 1.5 irradiation （100 mW/cm2） in comparison with the reference Ru-complex （N719 dye） with an r/value of 5.90% under similar experimental conditions.

Monolithic all-solid-state dye-sensitized solar cells

As a low-cost photovoltaic technology, dye- sensitized solar cell （DSSC） has attracted widespread attention in the past decade. During its development to commercial application, decreasing the production cost and increasing the device stability take the most impor- tance. Compared with conventional sandwich structure liquid-state DSSCs, monolithic all-solid-state mesoscopic solar cells based on mesoscopic carbon counter electrodes and solid-state electrolytes present much lower production cost and provide a prospect of long-term stability. This review presents the recent progress of materials and achievement for all-solid-state DSSCs. In particular, representative examples are highlighted with the results of our monolithic all-solid-state mesoscopic solar cell devices and modules.

铼联吡啶系列光敏染料的研究

设计合成了 2 ,2′ 联吡啶 4,4′ 二羧酸乙酯与过渡金属铼的系列络合物 [fac Re( 4 ,4′ di COOEt bpy) (CO) 3 (Xpy)PF6](其中bpy =2 ,2′ 联吡啶 ;py =吡啶 ;X =3 CH3 ,3 OH ,3 NH2 和H) ,对它们的电化学性能、紫外可见吸收、荧光激发和发射光谱进行了研究 .结果表明 ,随着吡啶环上取代基供电子能力的增强 ,H <CH3 <OH <NH2 ,Re(II/I)的氧化电位降低 ,减小了电子回传的驱动力 ;MLCT最大吸收波长变化不大 ,最大发射波长略有蓝移 ,荧光强度减弱 。

染料敏化纳米晶体光电池

对染料敏化纳米晶体太阳能电池 (Dye -SensitizedNanocrystallinePhotovoltaicSolarCells)的结构、工作原理进行了介绍 ,概述了它的研究现状及存在问题 ,指出它是一种非常有前途的清洁太阳能装置 ,具有结构简单 ,成本低廉 ,易于制造等优点 ,对光强度变化和温度变化不敏感 ,光电转换效率高 ,光稳定性好 ,对环境无污染 ,自 1 991年问世以来 ,引起了人们的广泛关注。并对这一研究领域的前景进行了展望。

铼联吡啶系列光敏染料的合成

In order to study the effects of the substituted groups on the properties of the complexes, a series of rhenium(Ⅰ) 2,2′-bipyridyl complexes [fac-(4,4′-di-COOEt-bpy)Re(CO) 3(X—pyridine)PF 6], where bpy is 2,2′-bipyridine and X is 4-methyl, 3-hydroxy, 4-hydroxy, 4-amino, or H, were synthesized with a yield more than 90%, and characterized by 1H NMR, 13C NMR, 2D-NMR( 1H- 1H COSY, HMBC, HSQC), ESI-MS and HRMS. The δ H values on the X—pyridine ring were shifted to up-field in 1H NMR and the MLCT absorbance maxima were red-shifted as the X groups became more electron-donating from H to 4-methyl, 4-hydroxy or 4-amino. The ESI-MS and HRMS showed the mono-charged peaks and their isotopic peaks of the complexes. The absorption maximum of 1d(X= 4-amino) is 20 nm longer than that of 1e(X=H). It might be used to broaden the absorption range of solar cells.

闪锌矿CdSe纳米晶的可控合成及其与MEH-PPV共混光电池的器件性能研究

采用溶剂热方法制备了闪锌矿CdSe纳米颗粒，利用TEM、XRD、荧光分析仪对其形貌、结构及光学性能进行了表征。结果表明，纳米颗粒的直径在3～5nm左右，为闪锌矿结构；其吸收峰在600nm左右，并与合成CdSe纳米晶所用的羧酸盐的链长略有差别；将CdSe与MEH-PPV（聚苯乙烯撑）共混，发现有明显的荧光淬灭现象；共混材料制成光电池器件，在模拟太阳光照射下获得了0．85％的能量转化效率。

纳米晶体太阳能电池及染料敏化剂

介绍了纳米晶体太阳能电池(Nanocrystalline Photovoltaic Cells,简称NPC)的结构和工作原理,概述了NPC电池所用染料敏化剂的研究现状及问题。

一维带状SnO_2的电子传输性能

采用水辅助化学气相沉积法制备了结晶性好的一维带状SnO2.分别以小粒径锡粉和金修饰的小粒径锡粉作为反应原料制得带宽度不同的带状SnO2,小粒径锡粉作为反应原料能提高带状SnO2的产率.将所得SnO2带和SnO2纳米颗粒按不同比例混合配制成胶体,采用刮涂法制备含不同比例纳米颗粒和纳米带的复合SnO2薄膜并组装染料敏化太阳能电池(DSSCs)来评价带状SnO2的电子输运性能.组装的太阳能电池表现出与复合纳晶薄膜中一维SnO2带的带宽度和所含比例密切相关的光电性能.通过强度调制光电流谱的测量确定复合SnO2薄膜的电子传输速率,并进一步分析一维材料所具有的良好电子传输性能对光电流增加的贡献.因为一维SnO2带在复合纳晶薄膜中作为电子输运的快速通道可以加快电子的输运速度,所以以适宜的比例添加具有合适宽度的一维SnO2带可以明显提高太阳能电池的光电性能.

Recent progress of thin-film photovoltaics for indoor application

Indoor photovoltaics have attracted increasing attentions owing to their great potential in supplying energy for low power devices under indoor light in our daily life.The third generation thin-film solar cells,including dye-sensitized solar cells,perovskite solar cells and organic solar cells,have made rapid progress from the aspect of materials design to photovoltaic performance.This review provides an overview on the recent advances in the development of indoor photovoltaic technologies based on the third generation solar cells.The design principles of advanced thin-film indoor photovoltaics were also summarized according to the characteristics of indoor light and the advantages of the third generation solar cells.Finally,after summarizing the current research progress,the perspective on this topic is provided.

Efficient light harvesting from flexible perovskite solar cells under indoor white light-emitting diode illumination

This is the first report of an investigation on flexible perovskite solar cells for artificial light harvesting by using a white light-emitting diode （LED） lamp as a light source at 200 and 400 Ix, values typically found in indoor environments. Flexible cells were developed using either low-temperature sol-gel or atomic- layer-deposited compact layers over conducting polyethylene terephthalate （PET） substrates, together with ultraviolet （UV）-irradiated nanoparticle TiO2 scaffolds, a CH3NHBPbI3xClx perovskite semiconductor, and a spiro-MeOTAD hole transport layer. By guaranteeing high-quality carrier blocking （via the 10-40 nm-thick com- pact layer） and injection （via the nanocrystalline scaffold and perovskite layers） behavior, maximum power conversion efficiencies （PCE） and power densities of 10.8% and 7.2 pW-cm-2, respectively, at 200 lx, and 12.1% and 16.0 -tW＇cm-2, respectively, at 400 lx were achieved. These values are the state-of-the-art, comparable to and even exceeding those of flexible dye-sensitized solar cells under LED lighting, and significantly greater than those for flexible amorphous silicon, which are currently the main flexible photovoltaic technologies commercially considered for indoor applications. Furthermore, there are significant margins of improvement for reaching the best levels of efficiency for rigid glass-based counterparts, which we found was a high of PCE -24% at 400 lx. With respect to rigid devices, flexibility brings the advantages of being low cost, lightweight, very thin, and COlfformal, which is especially important for seamless integration in indoor environments.

纳米结构材料在太阳电池中的应用

各种纳米结构材料具有许多优异的光伏性质。例如量子阱具有良好的带隙可调谐能力,纳米薄膜具有较好的光吸收特性,量子点具有多激子产生能力,纳米线具有低反射特性等。重点评述了采用量子阱、纳米薄膜、各种一维纳米结构、纳米晶粒或量子点等不同纳米结构材料,制作的太阳电池的光伏性能及其近年研究进展。指出了各自的潜在优势与存在问题,并提出了设计与制作新型纳米结构太阳电池的若干技术对策,如选择合适的纳米结构材料、制备有序的量子点结构、设计叠层结构等一系列技术手段,借以提高太阳电池的光电转换效率。可以预期,高效率、低成本和长寿命的纳米结构太阳电池将会对未来光伏产业的发展产生重要影响。