双链结构有机光敏染料的合成及性能

设计合成了2个含双D-π-A结构的新型有机光敏染料DP1和DP2,利用高分辨质谱(HRMS)、核磁共振氢谱及核磁共振碳谱对其结构进行了表征。 研究了2个染料的光物理和电化学性质,并将其应用于染料敏化太阳能电池(DSSCs)的制作中。 在100×10-3 W/cm2(AM 1.5) 模拟太阳光的照射下,由染料DP2所制备的敏化太阳能电池的光电转化效率为4.10%;开路电压(Voc)、短路电流密度(Jsc)和填充因子(FF)分别为0.63 V、8.59×10-3 A/cm2和0.76。 而在同等条件下,由染料DP1所制作的染料敏化电池光电转化效率为3.83%。     

High-Performance Dipolar Organic Dyes with an Electron-Deficient Diphenylquinoxaline Moiety in the π-Conjugation Framework for Dye-Sensitized Solar Cells

We report here the synthesis and electrochemical and photophysical properties of a series of easily prepared dipolar organic dyes and their application in dye-sensitized solar cells (DSSCs). For the six organic dyes, the molecular structures comprised a triphenylamine group as an electron donor, a cyanoacrylic acid as an electron acceptor, and an electron-deficient diphenylquinoxaline moiety integrated in the π-conjugated spacer between the electron donor and acceptor moieties. The incorporation of the electron-deficient diphenylquinoxaline moiety effectively reduces the energy gap of the dyes and broadly extends the spectral coverage. DSSCs based on dye 6 produced the best overall cell performance of 7.35?%, which translates to approximately 79?% of the intrinsic efficiency of the DSSCs based on the standard N719 dye under identical experimental conditions. The high performance of DSSCs based on dye 6 among the six dyes explored is attributed to the combined effects of high dye loading on a TiO(2) surface, rapid dye regeneration, and effective retardation of charge recombination.     

High‐Performance Dipolar Organic Dyes with an Electron‐Deficient Diphenylquinoxaline Moiety in the π‐Conjugation Framework for Dye‐Sensitized Solar Cells

We report here the synthesis and electrochemical and photophysical properties of a series of easily prepared dipolar organic dyes and their application in dye‐sensitized solar cells (DSSCs). For the six organic dyes, the molecular structures comprised a triphenylamine group as an electron donor, a cyanoacrylic acid as an electron acceptor, and an electron‐deficient diphenylquinoxaline moiety integrated in the π‐conjugated spacer between the electron donor and acceptor moieties. The incorporation of the electron‐deficient diphenylquinoxaline moiety effectively reduces the energy gap of the dyes and broadly extends the spectral coverage. DSSCs based on dye 6 produced the best overall cell performance of 7.35 %, which translates to approximately 79 % of the intrinsic efficiency of the DSSCs based on the standard N719 dye under identical experimental conditions. The high performance of DSSCs based on dye 6 among the six dyes explored is attributed to the combined effects of high dye loading on a TiO₂ surface, rapid dye regeneration, and effective retardation of charge recombination.     

Photophysical and Electrochemical Properties,and Molecular Structures of Organic Dyes for Dye‐Sensitized Solar Cells

Dye‐sensitized solar cells (DSSCs) based on organic dyes adsorbed on oxide semiconductor electrodes, such as TiO₂, ZnO, or NiO, which have emerged as a new generation of sustainable photovoltaic devices, have attracted much attention from chemists, physicists, and engineers because of enormous scientific interest in not only their construction and operational principles, but also in their high incident‐solar‐light‐to‐electricity conversion efficiency and low cost of production. To develop high‐performance DSSCs, it is important to create efficient organic dye sensitizers, which should be optimized for the photophysical and electrochemical properties of the dyes themselves, with molecular structures that provide good light‐harvesting features, good electron communication between the dye and semiconductor electrode and between the dye and electrolyte, and to control the molecular orientation and arrangement of the dyes on a semiconductor surface. The aim of this Review is not to make a list of a number of organic dye sensitizers developed so far, but to provide a new direction in the epoch‐making molecular design of organic dyes for high photovoltaic performance and long‐term stability of DSSCs, based on the accumulated knowledge of their photophysical and electrochemical properties, and molecular structures of the organic dye sensitizers developed so far.     

Structure–Performance Correlations of Organic Dyes with an Electron‐Deficient Diphenylquinoxaline Moiety for Dye‐Sensitized Solar Cells

The high performances of dye‐sensitized solar cells (DSSCs) based on seven new dyes are disclosed. Herein, the synthesis and electrochemical and photophysical properties of a series of intentionally designed dipolar organic dyes and their application in DSSCs are reported. The molecular structures of the seven organic dyes are composed of a triphenylamine group as an electron donor, a cyanoacrylic acid as an electron acceptor, and an electron‐deficient diphenylquinoxaline moiety integrated in the π‐conjugated spacer between the electron donor and acceptor moieties. The DSSCs based on the dye DJ104 gave the best overall cell performance of 8.06 %; the efficiency of the DSSC based on the standard N719 dye under the same experimental conditions was 8.82 %. The spectral coverage of incident photon‐to‐electron conversion efficiencies extends to the onset at the near‐infrared region due to strong internal charge‐transfer transition as well as the effect of electron‐deficient diphenylquinoxaline to lower the energy gap in these organic dyes. A combined tetraphenyl segment as a hydrophobic barrier in these organic dyes effectively slows down the charge recombination from TiO₂ to the electrolyte and boosts the photovoltage, comparable to their Ru^II counterparts. Detailed spectroscopic studies have revealed the dye structure–cell performance correlations, to allow future design of efficient light‐harvesting organic dyes.     

Nanocrystalline electrodes based on nanoporous-walled WO3 nanotubes for organic-dye-sensitized solar cells

Nanoporous-walled tungsten oxide (WO(3)) nanotubes (NTs), which had a more positive conduction band edge level compared to that of TiO(2), were applied to various organic dyes for dye-sensitized solar cells (DSSCs). The dye-sensitized WO(3) NTs displayed photosensitization for the organic dyes whose lowest unoccupied molecular orbital (LUMO) level was relatively positive to the conventional TiO(2) electrode and, thus, not applicable for electron injection to the TiO(2) electrode. Electron transport time and electron lifetime for the WO(3) electrode in the DSSCs were investigated. In comparison to the DSSCs based on TiO(2), SnO(2), and In(2)O(3), the WO(3) DSSCs displayed the longest lifetime. On the other hand, non-diffusion-like electron transport may be an issue to apply WO(3) for the DSSCs.     

Photovoltaic Performance of Triphenylamine Dyes-sensitized Solar Cells Employing Cobalt Redox Shuttle and Influence of π-conjugated Spacers

Developing photosensitizers suitable for the cobalt electrolyte and understanding the structure-property relationship of organic dyes is warranted for the dye-sensitized solar cells (DSSCs). The DSSCs incorporating tris(1,10-phenanthroline)cobalt(II/III)-based redox elec-trolyte and four synthesized organic dyes as photosensitizers are described. The photovoltaic performance of these dyes-sensitized solar cells employing the cobalt redox shuttle and the influences of the π-conjugated spacers of organic dyes upon the photovoltage and photocur-rent of mesoscopic titania solar cells are investigated. It is found that organic dyes with thiophene derivates as linkers are suitable for DSSCs employing cobalt electrolytes. DSSCs sensitized with the as-synthesized dyes in combination with the cobalt redox shuttle yield an overall power conversion efficiency of 6.1% under 100 mW/cm² AM1.5 G illumination.     

Influence of surface-attachment functionality on the aggregation, persistence, and electron-transfer reactivity of chalcogenorhodamine dyes on TiO2

Chalcogenorhodamine dyes bearing phosphonic acids and carboxylic acids were compared as sensitizers of nanocrystalline TiO(2) in dye-sensitized solar cells (DSSCs). The dyes were constructed around a 3,6-bis(dimethylamino)chalcogenoxanthylium core and varied in the 9 substituent: 5-carboxythien-2-yl in dyes 1-E (E = O, Se), 4-carboxyphenyl in dyes 2-E (E = O, S), 5-phosphonothien-2-yl in dyes 3-E (E = O, Se), and 4-phosphonophenyl in dyes 4-E (E = O, Se). All dyes adsorbed to TiO(2) as mixtures of H aggregates and monomers, which exhibited broadened absorption spectra relative to those of purely amorphous monolayers. Surface coverages of dyes and the extent of H aggregation varied minimally with the surface-attachment functionality, the structure of the 9-aryl group, and the identity of the chalcogen heteroatom. Carboxylic acid-functionalized dyes 1-E and 2-E desorbed rapidly and completely from TiO(2) into acidified CH(3)CN, but phosphonic acid-functionalized dyes 3-E and 4-E persisted on TiO(2) for days. Short-circuit photocurrent action spectra of DSSCs corresponded closely to the absorptance spectra of dye-functionalized films; thus, H aggregation did not decrease the electron-injection yield or charge-collection efficiency. Maximum monochromatic incident photon-to-current efficiencies (IPCEs) of DSSCs ranged from 53 to 95% and were slightly higher for carboxylic acid-functionalized dyes 1-E and 2-E. Power-conversion efficiencies of DSSCs under white-light illumination were low (<1%), suggesting that dye regeneration was inefficient at high light intensities. The photoelectrochemical performance (under monochromatic or white-light illumination) of 1-E and 2-E decayed significantly within 20-80 min of the assembly of DSSCs, primarily because of the desorption of the dyes. In contrast, the performance of phosphonic acid-functionalized dyes remained stable or improved slightly on similar timescales. Thus, replacing carboxylic acids with phosphonic acids increased the inertness of chalcogenorhodamine-TiO(2) interfaces without greatly impacting the aggregation of dyes or the interfacial electron-transfer reactivity.     

Dipolar Compounds Containing Fluorene and a Heteroaromatic Ring as the Conjugating Bridge for High‐Performance Dye‐Sensitized Solar Cells

A novel series of dipolar organic dyes containing diarylamine as the electron donor, 2‐cyanoacrylic acid as the electron acceptor, and fluorene and a heteroaromatic ring as the conjugating bridge have been developed and characterized. These metal‐free dyes exhibited very high molar extinction coefficients in the electronic absorption spectra and have been successfully fabricated as efficient nanocrystalline TiO₂ dye‐sensitized solar cells (DSSCs). The solar‐energy‐to‐electricity conversion efficiencies of DSSCs ranged from 4.92 to 6.88 %, which reached 68–96 % of a standard device of N719 fabricated and measured under the same conditions. With a TiO₂ film thickness of 6 μm, DSSCs based on these dyes had photocurrents surpassing that of the N719‐based device. DFT computation results on these dyes also provide detailed structural information in connection with their high cell performance.     

Highly efficient organic indolocarbazole dye in different acceptor units for optoelectronic applications—a first principle study

A series of novel organic dyes (ICZA1, ICZA2, ICZA3, ICZA4) with D-π-A structural configuration incorporating indolo[3,2,1-jk]carbazole moiety as donor (D) unit, thiophene as π-linker and 2-cyanoacrylic acid as acceptor unit were investigated using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods. Indolo[3,2,1-jk]carbazole-based D-π-A dyes composed of different acceptor groups were designed. By modulating acceptor unit, the efficiency of D-π-A dye-based dye-sensitized solar cells (DSSCs) can be further improved. In the present work, four novel push-pull organic dyes only differing in electron acceptor, have been designed based on the experimental literature value of IC-2. In order to further improve the light harvesting capability of indolo[3,2,1-jk]carbazole dyes, the acceptor influence on the dye performance were examined. The NLO property of the designed dye molecules can be derived as polarizability and hyperpolarizability. The calculated value of ICZA2 dye is the best candidate for NLO properties. Furthermore, the designed organic dyes exhibit good photovoltaic performance of charge transfer characteristics, driving force of electron injection, dye regeneration, global reactivity, and light harvesting efficiency (LHE). From the calculated value of ICZA4 dye, it has been identified as a good candidate for DSSCs applications. Finally, it is concluded that the both ICZA2 and ICZA4 dyes theoretically agrees well with the experimental value of IC-2 dye. Hence, the dyes ICZA2 and ICZA4 can serve as an excellent electron withdrawing groups for NLO and DSSCs applications.     

Starburst triarylamine based dyes for efficient dye-sensitized solar cells

We report here on the synthesis and photophysical/electrochemical properties of a series of novel starburst triarylamine-based organic dyes (S1, S2, S3, and S4) as well as their application in dye-sensitized nanocrystalline TiO2 solar cells (DSSCs). For the four designed dyes, the starburst triarylamine group and the cyanoacetic acid take the role of electron donor and electron acceptor, respectively. It was found that the introduction of starburst triarylamine group to form the D-D-pi-A configuration brought about superior performance over the simple D-pi-A configuration, in terms of bathochromically extended absorption spectra, enhanced molar extinction coefficients and better thermo-stability. Moreover, the HOMO and LUMO energy levels tuning can be conveniently accomplished by alternating the donor moiety, which was confirmed by electrochemical measurements and theoretical calculations. The DSSCs based on the dye S4 showed the best photovoltaic performance: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 85%, a short-circuit photocurrent density (J(sc)) of 13.8 mA cm(-2), an open-circuit photovoltage (V(oc)) of 0.63 V, and a fill factor (ff) of 0.69, corresponding to an overall conversion efficiency of 6.02% under 100 mW cm(-2) irradiation. This work suggests that the dyes based on starburst triphenylamine donor are promising candidates for improvement of the performance of the DSSCs.     

Organic Dyes with Well‐Defined Structures for Highly Efficient Dye‐Sensitised Solar Cells Based on a Cobalt Electrolyte

Seven SGT organics dyes, containing bis‐dimethylfluoreneyl amino groups with a dialkoxyphenyl unit as an electron donor and a cyanoacrylic acid group as an anchoring group, connected with oligothiophenes, fused thiophenes and benzothiadiazoles as π‐bridges, were designed and synthesised for applications in dye‐sensitised solar cells (DSSCs). The photovoltaic performance of DSSCs based on organic dyes with oligothiophenes depends on the molecular structure of the dyes, in terms of the length change of the π‐bridging units. The best performance was found with a π‐bridge length of about 6 Å. To further enhance the photovoltaic performance associated with this concept, cyclopenta[1,2‐b:5,4‐b′]dithiophene (CPDT) and benzothiadiazole were introduced into the π‐bridge unit. As a result, the DSSC based on the organic dye containing the CPDT moiety showed the best photovoltaic performance with a short‐circuit photocurrent density (J_sc) of 14.1 mA cm^?2, an open‐circuit voltage (V_oc) of 0.84 V and a fill factor (FF) of 0.72, corresponding to an overall conversion efficiency (η) of 8.61 % under standard AM 1.5 irradiation.     

Theoretical investigation of triphenylamine dye/titanium dioxide interface for dye-sensitized solar cells

The structural, electronic and optical features of two metal-free triphenylamine (TPA) organic dyes (namely C206 and C217) before and after binding to a TiO(2) anatase nanoparticle have been investigated in detail, as a model for the corresponding dye-sensitized solar cells (DSSCs). The combination of density functional tight-binding (DFTB), density functional theory (DFT), and time-dependent DFT (TDDFT) approaches are employed. To understand the effects of the linker part in the TPA organic dyes on the energy conversion efficiency of the DSSCs, C217 and C206, which share the same donor and anchor parts but different linker parts, are theoretically evaluated. Our results show that compared with C206 containing just one thienothiophene unit as the linker, for C217 the introduction of one electron-rich 3,4-ethylenedioxythiophene group to the linker part results in stronger couplings with the TiO(2) conduction band and more efficient electron transfer. This difference contributes to the higher efficiency of C217 in DSSCs experiments. This study is expected to assist the molecular design of new and more efficient TPA-based organic dyes for the optimization of the DSSCs.     

Exploration on Charge Transfer and Absorption Spectra of Spiro[fluorene-9,90-xanthene]-based Polyoxometalate Hybrids Toward High Performance Dye-sensitized Solar Cell

Based on spiro[fluorene-9,90-xanthene](SFX, dye 1), the Lindqvist-type polyoxometalate(POM) functionalized with SFX and its derivatives(dyes 2-4) used in dye-sensitized solar cells(DSSCs) were designed and investigated with the density functional theory(DFT) and time-dependent DFT(TD-DFT) calculations. The results indicate that Lindqvist-type POM is the main contribution to the lowest unoccupied molecular orbital(LUMO) and affects the LUMO energies of dyes 2-4. The maximum absorptions of the designed dyes containing POM(dyes 2-4) are red shifted comparing with that of dye 1. The introduction of electron-donating group onto SFX segment is helpful to red shift the absorption spectra. The major factors affecting the performance of DSSCs, including light harvesting and electron injection were evaluated. Considering the absorption spectra and photovoltaic parameters, dyes 3 and 4 are promising high performance dye sensitizers in n-type DSSCs.     

The Structure‐property Relationships of D‐π‐A BODIPY Dyes for Dye‐sensitized Solar Cells

BODIPY dyes have attracted considerable attention as potential photosensitizers in dye‐sensitized solar cells (DSSCs) owing to their excellent optical properties and facile structural modification. This account focuses on recent advances in the molecular design of D‐π‐A BODIPY dyes for applications in DSSCs. Special attention has been paid to the structure‐property relationships of D‐π‐A BODIPY dyes for DSSCs. The developmental process in the modified position at the BODIPY core with a donor/acceptor is described. The devices based on 2,6‐modified BODIPY dyes exhibit better photovoltaic performance over other modified BODIPY dyes. Meanwhile, the research reveals the correlation of molecular structures (various donor chromophores, extended units, molecular frameworks, and long alkyl groups) with their photophysical and electrochemical properties and relates it to their performance in DSSCs. The structure‐property relationships give valuable information and guidelines for designing new D‐π‐A BODIPY dyes for DSSCs.

     

New tetrazole-based organic dyes for dye-sensitized solar cells

A series of new metal-free organic dyes that contain donors with triphenylamine or its derivatives and tetrazole-based acceptors were synthesized and characterized by photophysical, electrochemical, and theoretical computational methods. They were applied in nanocrystalline TiO_2 solar cells(DSSCs). It is found that the introduction of diphenylamine units as antennas in the as-synthesized dyes could improve photovoltaic performance compared with phenothiazine and carbazole units as antennas in DSSCs. The dye with(2H-tetrazol-5-yl) acrylonitrile electron acceptor also displayed the highest solar-to-electrical energy conversion efficiency.     

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。     

Effect of chenodeoxycholic acid (CDCA) additive on phenothiazine dyes sensitized photovoltaic performance

The effects of chenodeoxycholic acid (CDCA) in a dye solution as a co-adsorbent on the photovoltaic performance of dye-sensitized solar cells (DSSCs) based on two organic dyes containing phenothiazine and triarylamine segments (P1 and P2) were investigated.It was found that the coadsorption of CDCA can hinder the formation of dye aggregates and improve electron injection yield and thus Jsc.This has also led to a rise in photovoltage,which is attributed to the decrease of charge recombination.The DSSC based ...     

Oligothiophene-containing coumarin dyes for efficient dye-sensitized solar cells

We have developed oligothiophene-containing coumarin dyes fully functionalized for dye-sensitized nanocrystalline TiO(2) solar cells (DSSCs). DSSCs based on the dyes gave good performance in terms of incident photon-to-current conversion efficiency (IPCE) in the range of 400-800 nm. A solar energy-to-electricity conversion efficiency (eta) of 7.4% was obtained with a DSSC based on 2-cyano-3-[5'-(1,1,6,6-tetramethyl-10-oxo-2,3,5,6-tetrahydro-1H,4H,10H-11-oxa-3a-aza-benzo[de]anthracen-9-yl)-[2,2']bithiophenyl-5-yl]acrylic acid (NKX-2677) under simulated AM 1.5G irradiation (100 mW cm(-2)) with a mask: short-circuit current density (J(sc)) = 13.5 mA cm(-2); open-circuit voltage (V(oc)) = 0.71 V; fill factor (FF) = 0.77. Transient absorption spectroscopy measurements indicated that electron injection from NKX-2677 to the conduction band of TiO(2) is very rapid (<100 fs), which is much faster than the emission lifetime of the dye (1.0 ns), giving a highly efficient electron injection yield of near unity.     

染料敏化太阳能电池中二聚噻吩类光敏染料构效关系的理论研究

D-π-A型有机光敏染料结构上的微小差异会引起器件性能的显著不同. 为了合理解释染料分子1和2(给体分别为咔唑和二氢吲哚)结构与性能之间的关系, 采用密度泛函理论(DFT)和含时密度泛函理论(TD-DFT)讨论了包括紫外-可见吸收光谱、 光捕获效率、 电子注入驱动力、 垂直方向偶极矩和电子转移数目在内的一系列影响染料性能的理论参数. 结果表明, 在光捕获效率和电子注入效率差别不大的情况下, 染料分子2较低的染料再生效率可导致其短路电流较小; 同时, 在由光诱导产生的从染料分子转移到半导体的电子数目以及电子复合程度相差不大的情况下, 染料分子1垂直方向上较大的偶极矩则可导致其具有较高的开路电压. 计算结果与实验值相吻合, 有望对今后设计合成高效光敏染料提供一定的理论指导.