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1.
Molecular Engineering of Pyrido[3,4‐b]pyrazine‐Based Donor–Acceptor–π‐Acceptor Organic Sensitizers: Effect of Auxiliary Acceptor in Cobalt‐ and Iodine‐Based Electrolytes 下载免费PDF全文
Dr. Bo Liu Dr. Fabrizio Giordano Dr. Kai Pei Dr. Jean‐David Decoppet Prof. Wei‐Hong Zhu Dr. Shaik M. Zakeeruddin Prof. Michael Grätzel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(51):18654-18661
Due to the ease of tuning its redox potential, the cobalt‐based redox couple has been extensively applied for highly efficient dye‐sensitized solar cells (DSSCs) with extraordinarily high photovoltages. However, a cobalt electrolyte needs particular structural changes in the organic dye components to obtain such high photovoltages. To achieve high device performance, specific requirements in the molecular tailoring of organic sensitizers still need to be met. Besides the need for large electron donors, studies of the auxiliary acceptor segment of donor–acceptor–π‐acceptor (D‐A‐π‐A) organic sensitizers are still rare in molecular optimization in the context of cobalt electrolytes. In this work, two novel organic D‐A‐π‐A‐type sensitizers ( IQ13 and IQ17 ) have been developed and exploited in cobalt‐ and iodine‐based redox electrolyte DSSCs, specifically to provide insight into the effect of π‐bridge modification in different electrolytes. The investigation has been focused on the additional electron‐withdrawing acceptor capability with grafted long alkoxy chains. Optoelectronic transient measurements have indicated that IQ17 containing a pyrido[3,4‐b]pyrazine moiety bearing long alkoxyphenyl chains is more suitable for application in cobalt‐based DSSCs. 相似文献
2.
Huiyun Jiang Yameng Ren Weiwei Zhang Yongzhen Wu Etienne Christophe Socie Brian Irving Carlsen Jacques‐E. Moser He Tian Shaik Mohammed Zakeeruddin Wei‐Hong Zhu Michael Grtzel 《Angewandte Chemie (International ed. in English)》2020,59(24):9324-9329
Dye‐sensitized solar cells (DSSCs) based on CuII/I bipyridyl or phenanthroline complexes as redox shuttles have achieved very high open‐circuit voltages (VOC, more than 1 V). However, their short‐circuit photocurrent density (JSC) has remained modest. Increasing the JSC is expected to extend the spectral response of sensitizers to the red or NIR region while maintaining efficient electron injection in the mesoscopic TiO2 film and fast regeneration by the CuI complex. Herein, we report two new D‐A‐π‐A‐featured sensitizers termed HY63 and HY64 , which employ benzothiadiazole (BT) or phenanthrene‐fused‐quinoxaline (PFQ), respectively, as the auxiliary electron‐withdrawing acceptor moiety. Despite their very similar energy levels and absorption onsets, HY64 ‐based DSSCs outperform their HY63 counterparts, achieving a power conversion efficiency (PCE) of 12.5 %. PFQ is superior to BT in reducing charge recombination resulting in the near‐quantitative collection of photogenerated charge carriers. 相似文献
3.
Ping Fang XIA Jianping Lu Chi Ho Kwok Hiroshi Fukutani Man Shing Wong Ye Tao 《Journal of polymer science. Part A, Polymer chemistry》2009,47(1):137-148
Two novel series of monodisperse multi‐triarylamine‐substituted oligothiophenes, G 2 ‐ OT ( n )‐ G 2 with thiophene unit (n) varying from 6 to 8, and 4,7‐bis(2′‐oligothienyl)‐2,1,3‐benzothiadiazoles G 2 ‐ OT ( n ) BTD ‐ G 2 (n = 2, 4, 6) have been synthesized by the Suzuki coupling reactions. With an elongation of alkyl‐substituted oligothiophene core or an incorporation of benzothiadiazole into the central core, the absorption and emission spectra of G 2 ‐ OT ( n )‐ G 2 and G 2 ‐ OT ( n ) BTD ‐ G 2 series red‐shift substantially with the optical gap reducing to 1.95 eV for G 2 ‐ OT ( 6 ) BTD ‐ G 2 . Alkyl‐substitution onto oligothiophene backbone not only improves the solubility of the highly extended dendrimers but also renders coplanarity of the dendritic oligothiophene backbone at the excited state, which results in the enhancement of fluorescence quantum efficiency. The bulk heterojunction solar cells using these newly synthesized dendritic oligothiophenes as a donor material and [6,6]‐phenyl C61‐butyric acid methyl ester (PCBM) as an acceptor material were fabricated and investigated which showed an increase in device performance as compared with those of the lower homologues. On increasing the loading of PCBM from 1.5 to 3 times in the active layer, there was also an enhancement in device performance with power conversion efficiencies of as‐fabricated solar cells increasing from 0.18% to 0.32%. In addition, proper annealing procedure could significantly improve the device performance of the dendrimer‐based photovoltaic cell. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 137–148, 2009 相似文献
4.
Ooyama Y Nagano T Inoue S Imae I Komaguchi K Ohshita J Harima Y 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(52):14837-14843
A new‐type of donor–acceptor π‐conjugated (D‐π‐A) fluorescent dyes NI3 – NI8 with a pyridine ring as electron‐withdrawing‐injecting anchoring group have been developed and their photovoltaic performances in dye‐sensitized solar cells (DSSCs) are investigated. The short‐circuit photocurrent densities and solar energy‐to‐electricity conversion yields of DSSCs based on NI3 – NI8 are greater than those for the conventional D‐π‐A dye sensitizers NI1 and NI2 with a carboxyl group as the electron‐withdrawing anchoring group. The IR spectra of NI3 – NI8 adsorbed on TiO2 indicate the formation of coordinate bonds between the pyridine ring of dyes NI3 – NI8 and the Lewis acid sites (exposed Tin+ cations) of the TiO2 surface. This work demonstrates that the pyridine rings of D‐π‐A dye sensitizers that form a coordinate bond with the Lewis acid site of a TiO2 surface are promising candidates as not only electron‐withdrawing anchoring group but also electron‐injecting group, rather than the carboxyl groups of the conventional D‐π‐A dye sensitizers that form an ester linkage with the Brønsted acid sites of the TiO2 surface. 相似文献
5.
Yen‐Ju Cheng Lung‐Chang Hung Fong‐Yi Cao Wei‐Shun Kao Chih‐Yu Chang Chain‐Shu Hsu 《Journal of polymer science. Part A, Polymer chemistry》2011,49(8):1791-1801
We have synthesized six p‐type copolymers, CPDT ‐ co ‐ TPADCN , CPDT ‐ co ‐ TPADTA , CPDT ‐ co ‐ TPATCN , CPDT ‐ co ‐ DFADCN , CPDT ‐ co ‐ DFADTA , and CPDT ‐ co ‐ DFATCN , consisting of a cyclopenta[2,1‐b:3,4‐b′]dithiophene (CPDT) unit and an organic dye in an alternating arrangement. Triphenylamine (TPA) or difluorenylphenyl amine (DFA) units serve as the electron donors, whereas dicyanovinyl (DCN), 1,3‐diethyl‐2‐thiobarbituric acid, or tricyanovinyl (TCN) units act as the electron acceptors in the dyes. The target polymers were prepared via Stille coupling, followed by postfunctionalization to introduce the electron acceptors to the side chains. Because of the strongest withdrawing ability of TCN acceptor to induce efficient intramolecular charge transfer, CPDT ‐ co ‐ TPATCN and CPDT ‐ co ‐ DFATCN exhibit the broader absorption spectra covering from 400 to 900 nm and the narrower optical band gaps of 1.34 eV. However, the CPDT ‐ co ‐ TPATCN :PC71BM and CPDT ‐ co ‐ DFATCN :PC71BM based solar cells showed the power conversion efficiencies (PCEs) of 0.22 and 0.31%, respectively, due to the inefficient exciton dissociation. The DFA‐based polymers possess deeper‐lying HOMO energy levels than the TPA‐based polymer analogues, leading to the higher Voc values and better efficiencies. The device based on CPDT ‐ co ‐ DFADTA :PC71BM blend achieved the best PCE of 1.38% with a Voc of 0.7 V, a Jsc of 4.57 mA/cm2, and a fill factor of 0.43. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
6.
Huimin Liu Kaixuan Wang Yinfeng Ma Yong Tian Houpeng Zhang Yu Wang Chaofan Zhong 《欧洲无机化学杂志》2023,26(15):e202200647
Donor-acceptor-π bridge-acceptor (D−A−π−A) motif dyes are promising dye sensitizers in dye-sensitized solar cells (DSSCs). In this study, to strengthen with-drawing electron force of the auxiliary electron acceptors(A) in D−A−π−A motif dye sensitizers, the metal complexes unit is be used as auxiliary electron acceptor(A) instead of organic electron-withdrawing monomer. The four polymeric metal complexes were designed, synthesized, and characterized, which used metal complexes of phenanthroline derivatives as auxiliary acceptors (A), benzodithiophene-dithiophene derivatives (BDTT) as donors (D), and 8-hydroxyquinoline derivatives as π-bridges and acceptors of the dye sensitizers, and have been used for dye sensitizers. Under AM 1.5 G (100 mW cm−2), the photovoltaic test results indicated that the short-circuit photocurrent density (Jsc) of the DSSCs based four polymeric metal complexes are 11.26, 13.68, 14.42 and 15.57 mA cm−2 and power conversion efficiency (PCE) are 5.96 %, 7.83 %, 8.07 %, 9.28 % respectively. Both Jsc and PCE value of the four polymeric metal complexes increased in order. This may be due to the fact that larger radius of metal ion under the same change number can enhance the coordination bond and cause stronger electron-withdrawing ability of auxiliary acceptor and stronger charge-transfer ability between the donor and the acceptor, which results in higher Jsc and higher PCE of the polymeric complex dye sensitizer. 相似文献
7.
Dr. Ming Cheng Prof. Xichuan Yang Dr. Jiajia Li Dr. Cheng Chen Dr. Jianghua Zhao Yu Wang Prof. Licheng Sun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(50):16196-16202
New hemicyanine dyes ( CM101 , CM102 , CM103 , and CM104 ) in which tetrahydroquinoline derivatives are used as electron donors and N‐(carboxymethyl)‐pyridinium is used as an electron acceptor and anchoring group were designed and synthesized for dye‐sensitized solar cells (DSSCs). Compared with corresponding dyes that have cyanoacetic acid as the acceptor, N‐(carboxymethyl)‐pyridinium has a stronger electron‐withdrawing ability, which causes the absorption maximum of dyes to be redshifted. The photovoltaic performance of the DSSCs based on dyes CM101 – CM104 markedly depends on the molecular structures of the dyes in terms of the n‐hexyl chains and methoxyl. The device sensitized by dye CM104 achieved the best conversion efficiency of 7.0 % (Jsc=13.4 mA cm?2, Voc=704 mV, FF=74.8 %) under AM 1.5 irradiation (100 mW cm?2). In contrast, the device sensitized by reference dye CMR104 with the same donor but the cyanoacetic acid as the acceptor gave an efficiency of 3.4 % (Jsc=6.2 mA cm?2, Voc=730 mV, FF=74.8 %). Under the same conditions, the cell fabricated with N719 sensitized porous TiO2 exhibited an efficiency of 7.9 % (Jsc=15.4 mA cm?2, Voc=723 mV, FF=72.3 %). The dyes CM101 – CM104 show a broader spectral response compared with the reference dyes CMR101 – CMR104 and have high IPCE exceeding 90 % from 450 to 580 nm. Considering the reflection of sunlight, the photoelectric conversion efficiency could be almost 100 % during this region. 相似文献
8.
Kai Pei Yongzhen Wu Wenjun Wu Dr. Qiong Zhang Baoqin Chen Prof. Dr. He Tian Prof. Dr. Weihong Zhu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(26):8190-8200
Four organic D–A –π‐A‐featured sensitizers (TQ1, TQ2, IQ1, and IQ2) have been studied for high‐efficiency dye‐sensitized solar cells (DSSCs). We employed an indoline or a triphenylamine unit as the donor, cyanoacetic acid as the acceptor/anchor, and a thiophene moiety as the conjugation bridge. Additionally, an electron‐withdrawing quinoxaline unit was incorporated between the donor and the π‐conjugation unit. These sensitizers show an additional absorption band covering the broad visible range in solution. The contribution from the incorporated quinoxaline was investigated theoretically by using DFT and time‐dependent DFT. The incorporated low‐band‐gap quinoxaline unit as an auxiliary acceptor has several merits, such as decreasing the band gap, optimizing the energy levels, and realizing a facile structural modification on several positions in the quinoxaline unit. As demonstrated, the observed additional absorption band is favorable to the photon‐to‐electron conversion because it corresponds to the efficient electron transitions to the LUMO orbital. Electrochemical impedance spectroscopy (EIS) Bode plots reveal that the replacement of a methoxy group with an octyloxy group can increase the injection electron lifetime by a factor of 2.4. IQ2 and TQ2 can perform well without any co‐adsorbent, successfully suppress the charge recombination from TiO2 conduction band to I3? in the electrolyte, and enhance the electron lifetime, resulting in a decreased dark current and enhanced open circuit voltage (Voc) values. By using a liquid electrolyte, DSSCs based on dye IQ2 exhibited a broad incident photon‐to‐current conversion efficiency (IPCE) action spectrum and high efficiency (η=8.50 %) with a short circuit current density (Jsc) of 15.65 mA cm?2, a Voc value of 776 mV, a fill factor (FF) of 0.70 under AM 1.5 illumination (100 mW cm?2). Moreover, the overall efficiency remained at 97 % of the initial value after 1000 h of visible‐light soaking. 相似文献
9.
Jinxiang He Fuling Guo Dr. Xin Li Wenjun Wu Jiabao Yang Prof. Dr. Jianli Hua 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(25):7903-7915
A series of new push–pull organic dyes ( BT‐I – VI ), incorporating electron‐withdrawing bithiazole with a thiophene, furan, benzene, or cyano moiety, as π spacer have been synthesized, characterized, and used as the sensitizers for dye‐sensitized solar cells (DSSCs). In comparison with the model compound T1 , these dyes containing a thiophene moiety between triphenylamine and bithiazole display enhanced spectral responses in the red portion of the solar spectrum. Electrochemical measurement data indicate that the HOMO and LUMO energy levels can be tuned by introducing different π spacers between the bithiazole moiety and cyanoacrylic acid acceptor. The incorporation of bithiazole substituted with two hexyl groups is highly beneficial to prevent close π–π aggregation, thus favorably suppressing charge recombination and intermolecular interaction. The overall conversion efficiencies of DSSCs based on bithiazole dyes are in the range of 3.58 to 7.51 %, in which BT‐I ‐based DSSCs showed the best photovoltaic performance: a maximum monochromatic incident photon‐to‐current conversion efficiency (IPCE) of 81.1 %, a short‐circuit photocurrent density (Jsc) of 15.69 mA cm?2, an open‐circuit photovoltage (Voc) of 778 mV, and a fill factor (ff) of 0.61, which correspond to an overall conversion efficiency of 7.51 % under standard global AM 1.5 solar light conditions. Most importantly, long‐term stability of the BT‐I – III ‐based DSSCs with ionic‐liquid electrolytes under 1000 h of light soaking was demonstrated and BT‐II with a furan moiety exhibited better photovoltaic performance of up to 5.75 % power conversion efficiency. 相似文献
10.
Effect of Substituents in Catechol Dye Sensitizers on Photovoltaic Performance of Type II Dye‐Sensitized Solar Cells 下载免费PDF全文
Dr. Yousuke Ooyama Masahiro Kanda Koji Uenaka Prof. Dr. Joji Ohshita 《Chemphyschem》2015,16(14):3049-3057
In order to provide a direction in molecular design of catechol (Cat) dyes for type II dye‐sensitized solar cells (DSSCs), the dye‐to‐TiO2 charge‐transfer (DTCT) characteristics of Cat dyes with various substituents and their photovoltaic performance in DSSCs are investigated. The Cat dyes with electron‐donating or moderately electron‐withdrawing substituents exhibit a broad absorption band corresponding to DTCT upon binding to TiO2 films, whereas those with strongly electron‐withdrawing substituents exhibit weak DTCT. This study indicates that the introduction of a moderately electron‐withdrawing substituent on the Cat moiety leads to not only an increase in the DTCT efficiency, but also the retardation of back electron transfer. This results in favorable conditions for the type II electron‐injection pathway from the ground state of the Cat dye to the conduction band of the TiO2 electrode by the photoexcitation of DTCT bands. 相似文献
11.
Oliver Langmar Ettore Fazio Peter Schol Gema delaTorre Rubn D. Costa Toms Torres Dirk M. Guldi 《Angewandte Chemie (International ed. in English)》2019,58(12):4056-4060
We designed and synthesized a series of novel electron‐accepting zinc(II)phthalocyanines (ZnPc) and probed them in p‐type dye sensitized solar cells (p‐DSSCs) by using CuO as photocathodes. By realizing the right balance between interfacial charge separation and charge recombination, optimized fill factors (FFs) of 0.43 were obtained. With a control over fill factors in p‐DSSCs in hand we turned our attemtion to t‐DSSCs, in which we combined for the first time CuO‐based p‐DSSCs with TiO2‐based n‐DSSCs using ZnPc and N719. In the resulting t‐DSSCs, the VOC of 0.86 V is the sum of those found in p‐ and n‐DSSCs, while the FF remains around 0.63. It is only the smaller Jscs in t‐DSSCs that limits the efficiency to 0.69 %. 相似文献
12.
Dr. Nguyen Van Nghia Dr. Saibal Jana Surendran Sujith Ji Yeon Ryu Prof. Junseong Lee Prof. Sang Uck Lee Prof. Min Hyung Lee 《Angewandte Chemie (International ed. in English)》2018,57(38):12483-12488
An approach to the design of nido‐carborane‐based luminescent compounds that can exhibit thermally activated delayed fluorescence (TADF) is proposed. 7,8‐Dicarba‐nido‐undecaboranes (nido‐carboranes) having various 8‐R groups (R=H, Me, i‐Pr, Ph) are appended to the meta or para position of the phenyl ring of the dimesitylphenylborane (PhBMes2) acceptor, forming donor–acceptor compounds (nido‐ m1 – m4 and nido‐ p1 – p4 ). The bulky 8‐R group and meta substitution of the nido‐carborane are essential to attain a highly twisted arrangement between the donor and acceptor moieties, leading to a very small energy splitting between the singlet and triplet excited states (ΔEST <0.05 eV for nido‐ m2 , ‐ m3 , and ‐ p3 ). These compounds exhibit efficient TADF with microsecond‐range lifetimes. In particular, nido‐ m2 and ‐ m3 display aggregation‐induced emission (AIE) with TADF properties. 相似文献
13.
Modification of D–A–π–A Configuration toward a High‐Performance Triphenylamine‐Based Sensitizer for Dye‐Sensitized Solar Cells: A Theoretical Investigation 下载免费PDF全文
Ruangchai Tarsang Vinich Promarak Taweesak Sudyoadsuk Supawadee Namuangruk Nawee Kungwan Siriporn Jungsuttiwong 《Chemphyschem》2014,15(17):3809-3818
In an attempt to shed light on how the addition of a benzothiadiazole (BTD) moiety influences the properties of dyes, a series of newly designed triphenylamine‐based sensitizers incorporating a BTD unit as an additional electron‐withdrawing group in a specific donor–acceptor–π‐acceptor architecture has been investigated. We found that different positions of the BTD unit provided significantly different responses for light absorption. Among these, it was established that the further the BTD unit is away from the donor part, the broader the absorption spectra, which is an observation that can be applied to improve light‐harvesting ability. However, when the BTD unit is connected to the anchoring group a faster, unfavorable charge recombination takes place; therefore, a thiophene unit was inserted between these two acceptors, providing redshifted absorption spectra as well as blocking unfavorable charge recombination. The results of our calculations provide valuable information and illustrate the potential benefits of using computation‐aided sensitizer design prior to further experimental synthesis. 相似文献
14.
Lifen Xiao Yuan Liu Qian Xiu Lirong Zhang Lihui Guo Hailiang Zhang Chaofan Zhong 《Journal of polymer science. Part A, Polymer chemistry》2010,48(9):1943-1951
Two novel main chain polymeric metal complexes containing 8‐hydroxyquinoline europium complexes and phenylethyl or fluorene units: 1,4‐Dioctyloxy‐2,5‐bis[2‐(8‐hydroxyquinoline)‐vinyl]‐benzene Eu(III) (3) and 2,7‐bis[2‐(8‐hydroxyquinoline)‐vinyl]‐9,9′‐diocthylfluorene Eu(III) (4) with donor–acceptor‐π‐conjugated structure (D‐π‐A) have been synthesized and investigated as dye sensitizers for dye‐sensitized solar cells dyes (DSSCs). They have been determined and studied by FT‐IR, TGA, DSC, GPC, Elemental analysis, UV–vis absorption spectroscopy, photoluminescence spectroscopy, cyclic voltammetry, and application in dye‐sensitized solar cells (DSSCs) as dye sensitizers. On the basis of optimized dye and molecular structure, they have shown solar‐to‐electricity conversion efficiency 2.25% for 3 (Jsc = 4.77 mA cm?2, Voc = 630 mV, FF = 0.75) and 3.04% for 4 (Jsc = 6.33 mA cm?2, Voc = 640 mV, FF = 0.75), under the illumination of AM1.5G, 100 mW/cm2. The IPCE of 3 and 4 are 30% and 46% at 400 nm, respectively. Besides, they showed good stabilities with thermal decomposition temperatures at 280 °C and 225 °C, respectively, which are suitable for DSSCs. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1943–1951, 2010 相似文献
15.
Eunwoo Lee Chanhoi Kim Prof. Jyongsik Jang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(31):10280-10286
High‐performance Förster resonance energy transfer (FRET)‐based dye‐sensitized solar cells (DSSCs) have been successfully fabricated through the optimized design of a CdSe/CdS quantum‐dot (QD) donor and a dye acceptor. This simple approach enables quantum dots and dyes to simultaneously utilize the wide solar spectrum, thereby resulting in high conversion efficiency over a wide wavelength range. In addition, major parameters that affect the FRET interaction between donor and acceptor have been investigated including the fluorescent emission spectrum of QD, and the content of deposited QDs into the TiO2 matrix. By judicious control of these parameters, the FRET interaction can be readily optimized for high photovoltaic performance. In addition, the as‐synthesized water‐soluble quantum dots were highly dispersed in a nanoporous TiO2 matrix, thereby resulting in excellent contact between donors and acceptors. Importantly, high‐performance FRET‐based DSSCs can be prepared without any infrared (IR) dye synthetic procedures. This novel strategy offers great potential for applications of dye‐sensitized solar cells. 相似文献
16.
Prof. Jie Xu Ligen Zhu Dong Fang Biao Chen Prof. Li Liu Prof. Luoxin Wang Prof. Weilin Xu 《Chemphyschem》2012,13(14):3320-3329
A series of metal‐free organic donor–π bridge–acceptor dyes are studied computationally using density functional theory (DFT) and time‐dependent DFT (TDDFT) approaches to explore their potential performances in dye‐sensitized solar cells (DSSCs). Taking triphenylamine (TPA) and cyanoacrylic acid moieties as donor and acceptor units, respectively, the effects of different substituents of the π linkers in the TPA‐based dyes on the energy conversion efficiency of the DSSCs are theoretically evaluated through optimized geometries, charge distributions, electronic structures, simulated absorption spectra, and free energies of injection. The results show that the molecular orbital energy levels and electron‐injection driving forces of the TPA dyes can be tuned by the introduction of substituents with different electron‐withdrawing or ‐donating abilities. The electron‐withdrawing substituent always lowers the energies of both frontier orbitals, while the electron‐donating one heightens them simultaneously. The efficiency trend of these TPA derivatives as sensitizers in DSSCs is also predicted by analyzing the light‐harvesting efficiencies and the free energies of injection. The following substituents are shown to increase the efficiency of the dye: OMe, OEt, OHe, and OH. 相似文献
17.
MP2/6-31 g(d) calculations were performed verifying the existences of blue-shifting X-C≡C-CF2-H…OH2 hydrogen bonds.Detailed analyses revealed that the interaction energy and donor-acceptor distance had good correlations with the substituent Hammett constants.However,the extent of C-H bond contraction and the blue shift of the C-H stretching vibration did not show any good correlation with the traditional substituent constants,indicating that certain more complicated mechanisms might be involved in the present systems.Nevertheless,it was found that highly electron-with-drawing susbtituents were not favorable to the C-H bond contraction,and it was suggested that the attractive interaction between water and the carbon of -CF2H probably played an important role in the blue shift. 相似文献
18.
Dr. Hironobu Ozawa Megumi Awa Dr. Takahiko Ono Prof. Dr. Hironori Arakawa 《化学:亚洲杂志》2012,7(1):156-162
The effects of the dye‐adsorption solvent on the performances of the dye‐sensitized solar cells (DSSCs) based on black dye have been investigated. The highest conversion efficiency (10.6 %) was obtained in the cases for which 1‐PrOH and the mixed solvent of EtOH and tBuOH (3:1 v/v) were employed as dye‐adsorption solvents. The optimized value for the dielectric constant of the dye‐adsorption solvent was found to be around 20. The DSSCs that used MeOH as a dye‐adsorption solvent showed inferior solar‐cell performance relative to the DSSCs that used EtOH, 1‐PrOH, 2‐PrOH, and 1‐BuOH. Photo‐ and electrochemical measurements of black dye both in solution and adsorbed onto the TiO2 surface revealed that black dye aggregates at the TiO2 surface during the adsorption process in the case for MeOH. Both the shorter electron lifetime in the TiO2 photoelectrode and the greater resistance in the TiO2–dye–elecrolyte interface, attributed to the dye aggregation at the TiO2 surface, cause the decrease in the solar‐cell performance of the DSSC that used MeOH as a dye adsorption solvent. 相似文献
19.
Dye‐Sensitized Solar Cells Based on (Donor‐π‐Acceptor)2 Dyes With Dithiafulvalene as the Donor 下载免费PDF全文
Ting‐Hui Lee Dr. Chih‐Yu Hsu You‐Ya Liao Dr. Hsien‐Hsin Chou Heather Hughes Prof. Dr. Jiann T. Lin 《化学:亚洲杂志》2014,9(7):1933-1942
Dipolar metal‐free sensitizers (D‐π‐A; D=donor, π=conjugated bridge, A=acceptor) consisting of a dithiafulvalene (DTF) unit as the electron donor, a benzene, thiophene, or fluorene moiety as the conjugated spacer, and 2‐cyanoacrylic acid as the electron acceptor have been synthesized. Dimeric congeners of these dyes, (D‐π‐A)2, were also synthesized through iodine‐induced dimerization of an appropriate DTF‐containing segment. Dye‐sensitized solar cells (DSSCs) with the new dyes as the sensitizers have cell efficiencies that range from 2.11 to 5.24 %. In addition to better light harvesting, more effective suppression of the dark current than the D‐π‐A dyes is possible with the (D‐π‐A)2 dyes. 相似文献
20.
Dr. Sie‐Rong Li Chuan‐Pei Lee Dr. Hui‐Tung Kuo Prof. Kuo‐Chuan Ho Dr. Shih‐Sheng Sun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(38):12085-12095
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. 相似文献