Enediyne as π linker in D–π–A dyes for dye-sensitized solar cells

Wang, Youfu; Dong, Luhua; Zheng, Zhiwei; Li, Xing; Xiong, Rulin; Hua, Jing; Hu, Aiguo

doi:10.1039/c5ra25938j

Cited by 2 publications

(3 citation statements)

References 47 publications

(58 reference statements)

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“…Overall, fused thiophene units such as 5 , 6 , 7 , and 8 among others, have been used as π‐conjugated linker to study photoelectronic properties in free metal dyes of the type A ‐bridge‐ D …”

Section: Methodsmentioning

confidence: 99%

Exploring the relevance of thiophene rings as bridge unit in acceptor‐bridge‐donor dyes on self‐aggregation and performance in DSSCs

et al. 2017

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The possibility of dye charge recombination in DSSCs remains a challenge for the field. This consists of: (a) back-transfer from the TiO to the oxidized dye and (b) intermolecular electron transfer between dyes. The latter is attributed to dye aggregation due to dimeric conformations. This leads to poor electron injection which decreases the photocurrent conversion efficiency. Most organic sensitizers are characterized by an Acceptor-Bridge-Donor (A-Bridge-D) arrangement that is commonly employed to provide charge separation and, therefore, lowering the unwanted back-transfer. Here, we address the intermolecular electron transfer by studying the dimerization and photovoltaic performance of a group of A-Bridge-D structured dyes. Specifically, eight famous sulfur containing π-bridges were analyzed (A and D remained fixed). Through quantum mechanical and molecular dynamics approaches, it was found that the formation of weakly stabilized dimers is allowed. The dyes with covalently bonded and fused thiophene rings as Bridges, 6d and 7d as well as 8d with a fluorene, would present high aggregation and, therefore, high probability of recombination processes. Conversely, using TiO cluster and surface models, delineated the shortest bridges to improve the adsorption energy and the stability of the system. Finally, the elongation of the bridge up to 2 and 3 units and their photovoltaic parameters were studied. These results showed that all the sensitizers are able to provide similar photocurrent outcomes, regardless of whether the bridge is elongated. © 2017 Wiley Periodicals, Inc.

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Section: Methodsmentioning

confidence: 99%

Exploring the relevance of thiophene rings as bridge unit in acceptor‐bridge‐donor dyes on self‐aggregation and performance in DSSCs

et al. 2017

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Typically, organic sensitizers consist of an electron donating group, a π-conjugated bridge and an electron accepting unit. [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] In addition, an anchoring group (usually comprising a carboxylic acid moiety, COOH) is introduced, that allows the chemical adsorption of the dye on the metal-oxide semiconductor.…”

Section: Introductionmentioning

confidence: 99%

“…Organic dyes used as sensitizers in dye-sensitized solar cells (DSSCs) have gained tremendous scientific attention because they exhibit low production costs, high molar extinction coefficients, and a large variety of structural modifications, which allow a specific tailoring of their properties at the molecular level to meet all of the application requirements. − Typically, organic sensitizers consist of an electron-donating group, a π-conjugated bridge, and an electron-accepting unit. − In addition, an anchoring group (usually comprising a carboxylic acid moiety, COOH) is introduced, which allows the chemical adsorption of the dye on the metal-oxide semiconductor. The most important process after light harvesting by the dye molecules is charge separation and electron injection from the dyes’ lowest unoccupied molecular orbital (LUMO) to the oxide semiconductor’s conduction band.…”

Section: Introductionmentioning

confidence: 99%

Solvent-Acidity-Driven Change in Photophysics and Significant Efficiency Improvement in Dye-Sensitized Solar Cells of a Benzothiazole-Derived Organic Sensitizer

Seintis

Şahın

Sigmundová³

et al. 2018

J. Phys. Chem. C

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The photophysics and solar cells efficiency of organic sensitizers comprising a cyanoacrylic acid group are greatly influenced by an equilibrium between the neutral ("non-deprotonated", COOH) and anionic ("deprotonated", COO -) forms, whose ratio depends on the solvent polarity and its H-bonding properties, dye concentration and temperature used. Herein, we report a detailed investigation on the relationship between the portions of COOH and COOdye forms and the photophysical and solar cell properties of an organic dipolar sensitizer, BTZA-II, bearing triphenylamine electron-donating and benzothiazole electron-withdrawing moieties. The photophysics has been studied by stationary and time-resolved fluorescence spectroscopy in apolar and polar solvents with a dye concentration ranging from 5×10 -7 M to 5×10 -5 M, also upon addition of small amounts of an external acid or base in order to change the solvent acidity, allowing us to distinguish the contribution and lifetime of the neutral and anionic form. The fluorescence of BTZA-II in apolar toluene originates from the neutral form, which has a lifetime of 1.9 ns. Addition of a strong base (1,8-diazabicyclo[5.4.0]undec-7-ene, DBU) shifts the equilibrium towards the less fluorescent anionic COOform with a lifetime of 1.1 ns. The situation is different in the polar acetonitrile, where the fluorescence of the anionic form dominates (with a lifetime of 2.0 ns). Adding small amounts of acetic acid (AcOH) protonates the COOform of the BTZA-II dye and reveals significant quenching of the fluorescence because of the increased contribution of the neutral species with a lifetime of 0.4-0.5 ns. This quenching of the neutral species in acetonitrile has been also observed in concentrated solutions and is due to excited state proton transfer. By contrast, the photophysics of a dye Btz-NPh2, similar to BTZA-II but without the cyanoacrylic acid group, is not affected upon adding acetic acid (H-donor) or DBU base (H-acceptor), that rules out the Brønsted-base role of the benzothiazole scaffold in the aforementioned observations. Finally, dye-sensitized solar cells (DSSCs) with a solid-state electrolyte were prepared from toluene and toluene+acid solutions. A significant increase of the solar cell efficiency, η, by 58% (η reaching a value of 4.9%) has been achieved after addition of a small, appropriate amount of acetic acid into the initial BTZA-II dye solution.3

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Enediyne as π linker in D–π–A dyes for dye-sensitized solar cells

Abstract: Three enediyne-bridged D–π–A dyes with different donor position and number are synthesized and their performance on DSSCs are investigated.

Cited by 2 publications

References 47 publications

Exploring the relevance of thiophene rings as bridge unit in acceptor‐bridge‐donor dyes on self‐aggregation and performance in DSSCs

Exploring the relevance of thiophene rings as bridge unit in acceptor‐bridge‐donor dyes on self‐aggregation and performance in DSSCs

Solvent-Acidity-Driven Change in Photophysics and Significant Efficiency Improvement in Dye-Sensitized Solar Cells of a Benzothiazole-Derived Organic Sensitizer

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