TD-DFT investigation of D–π–A organic dyes with thiophene moieties as π-spacers for use as sensitizers in DSSCs

Hasanein, Ahmed A.; Elmarassi, Yasser R.; Kassem, Eman N.

doi:10.1007/s00894-016-2978-0

Cited by 14 publications

(11 citation statements)

References 55 publications

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“…These dyes were connected using thiophene as π‐conjugated bridges and the photovoltaic properties confirm the suitable effects of the π‐conjugated bridge of the dye on the performance of the DSSC. Hasanein et al reported a series of metal‐free dyes with two or more thiophene moieties as π‐linkers, theirs results show the versatility of chemical structure modification as a tool for designing DSSC sensitizers with suitable efficiencies.…”

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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“…[51,[83][84][85] Moreover, DFT provides a range of functionals and amongst these, B3LYP has been found as a reliable functional for the determination of optical, electronic, as well as structural properties of smallto medium-sized organic molecules. [86][87][88][89] The results obtained, after benchmark tests based on experimental and theoretical data for various functionals, have shown that the results obtained with B3LYP are generally in good agreement with the corresponding experimental values. [90-94]-The optimized geometries were checked for any imaginary frequency in order to be sure enough that the optimized geometries represent the true minima.…”

Section: Computational Detailsmentioning

confidence: 97%

Exploring the effect of different coumarin donors on the optical and photovoltaic properties of azo‐bridged push‐pull systems: A theoretical approach

Manzoor

Niaz

Pandith

2019

Int J of Quantum Chemistry

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We report the theoretical modeling of various azo-bridged coumarin-purpurin systems. The effect of varying the donor (coumarin) part of this D-π-D-π-A system was analyzed in terms of opto-electronic and photovoltaic parameters such as HOMO, LUMO, HOMO-LUMO energy gap, λ max , light harvesting efficiency, charge injection efficiency, open voltage, reorganization energy by employing density functional theory as incorporated in Gaussian 03 set of codes. The dye-TiO 2 adsorbed systems were also studied using the same level of theory. It was found that just by varying the donor, although of same nature, there is a marked effect on the efficiency parameters of the dye sensitized solar cells based on such dyes. Also, the dye molecules were found to be good sensitizers for TiO 2 semiconductors. K E Y W O R D S DFT, DSSC, light harvesting efficiency, optoelectronic, photovoltaic parameters | INTRODUCTIONDue to the over exploitation of the natural resources coupled with the increasing levels of pollutions, there is immediate need to develop some alternative, clean resources of energy. In this regard, solar energy is the easily available and clean form of energy that can be well harnessed to meet our present as well as future energy demands. To convert this solar energy into usable forms we have some devices called photovoltaic solar devices and amongst them dye sensitized solar cells (DSSC) are better options, owing to their easy manufacture, cost effectiveness, and flexibility.With the advent of the DSSC technology the conversion of the solar energy to electricity became cheap than the traditional silicon-based photovoltaics. [1,2] Amongst DSSCs, those based on organic dye sensitizers have been found to be advantageous owing to their easy synthesis and low cost. The study of these organic metal free dye sensitizers for DSSCs are important as they have paved the way for designing DSSCs with better efficiencies in a cost effective manner. Organic dyes have exhibited higher conversion efficiencies up to 12.5% for carbazoles and indenoperylene electron-donor based dye sensitizers while as 12.8% efficiency has been achieved for triphenylamine-based dye using cobalt-based electrolyte system. [3,4] Amongst the organic sensitizers, those based on push-pull framework or donor-π-acceptor (D-π-A) form are worth mentioning These push-pull dye molecules are very promising due to their high molar extinction coefficient, cost effectiveness, and diversity. [5][6][7][8][9] Along with experimental studies, a number of theoretical researches have been carried out on various organic dyes. The theoretical studies have served as a tool for verifying the results found experimentally. As such, number of such studies has been carried out, such as those based on coumarins [10][11][12][13][14][15][16] and triphenylamine. [17][18][19][20] Theoretical studies by several researchers [15,[21][22][23][24][25] on NKX coumarin derivatives have been carried for understanding the relationship between the molecular properties of these dye sensitizers and the...

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“…To avoid that a mistake is perpetuated, it should be noted that in the literature there are several reports using a wrong relation to determine V oc (see, for instance, References. [65][66][67][68][69][70][71][72][73][74]). In those cases, a confusion is made with the driving force for charge injection from the dye into the semiconductor, ∆G inj , which is calculated as the difference between the energy of the excited state of the dye (lowest unoccupied molecular orbital in DFT calculations), E dye* , and the TiO 2 conduction band edge, E CB [10,63,75]:…”

Section: Quantities Relevant To Device Performancementioning

confidence: 99%

Photoexcitation Processes in Oligomethine Cyanine Dyes for Dye-Sensitized Solar Cells—Synthesis and Computational Study

et al. 2020

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We report density functional theory (DFT) calculations of three newly synthesized oligomethine cyanine-based dyes as potential TiO2-sensitizers in dye-sensitized solar cells. The three dyes have π-symmetry and the same acceptor side, terminating in the carboxylic anchor, but they differ through the π-bridge and the donor groups. We perform DFT and time-dependent DFT studies and present the electronic structure and optical properties of the dyes alone as well as adsorbed to the TiO2 nanocluster, to provide some predictions on the photovoltaic performance of the system. We analyze theoretically the factors that can influence the short circuit current and the open circuit voltage of the dye-sensitized solar cells. We examine the matching of the absorption spectra of the dye and dye-nanocluster system with the solar irradiation spectrum. We display the energy level diagrams and discuss the alignment between the excited state of the dyes and the conduction band edge of the oxide as well as between the redox level of the electrolyte and the ground state of the dyes. We determine the electron density of the key molecular orbitals and analyze comparatively the electron transfer from the dye to the semiconducting substrate. To put our findings in the right perspective we compare the results of our calculations with those obtained for a coumarin-based dye used in fabricating and testing actual devices, for which experimental data regarding the photovoltaic performance are available.

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TD-DFT investigation of D–π–A organic dyes with thiophene moieties as π-spacers for use as sensitizers in DSSCs

Cited by 14 publications

References 55 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

Exploring the effect of different coumarin donors on the optical and photovoltaic properties of azo‐bridged push‐pull systems: A theoretical approach

Photoexcitation Processes in Oligomethine Cyanine Dyes for Dye-Sensitized Solar Cells—Synthesis and Computational Study

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