Theoretical study of new donor-π-Acceptor compounds based on Carbazole, Thiophene and Benzothiadiazole for photovoltaic application as dye-sensitized solar cells (original) (raw)
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2011
In this paper, four carbazole-based D-D-π-A organic dyes code as CCT2A, CCT3A, CCT1PA and CCT2PA were reported. A series of these organic dyes containing identical donor and acceptor group but different π-system. The effect of replacing of thiophene by phenyl thiophene as π-system on the physical properties has been focused. The structural, energetic properties and absorption spectra were theoretically investigated by means of Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT). The results show that nonplanar conformation due to steric hindrance in donor part (cabazolecarbazole unit) of dye molecule can prevent unfavorable dye aggregation. By means of the TD-DFT method, the absorption spectra were calculated by B3LYP and BHandHLYP to study the affect of hybrid functional on the excitation energy (Eg). The results revealed the increasing of thiophene units not only resulted in decreasing of Eg, but also found the shifting of absorption spectra to hi...
Thieno[2,3-a]carbazole-based donor–π–acceptor organic dyes for efficient dye-sensitized solar cells
Tetrahedron, 2014
New donorepeacceptor organic dyes K-1 and K-2 containing thieno[2,3-a]carbazole as an electron donor were designed and synthesized for dye-sensitized solar cells (DSCs). Photophysical and electrochemical properties of K-dyes were investigated. DSCs based on K-dyes showed a high conversion efficiency of 6.6e6.7% with a J sc of 12.40e12.49 mA cm À2 and a V oc of 0.70e0.71 V. The molecular geometry calculation indicated that the existence of thienocarbazole donor in K-dyes enhanced the molecular planarity compared to the carbazole analogue dye MK-3. As a result, DSCs based on K-dyes showed high IPCEs, perhaps due to efficient intramolecular charge transfer and electron injection from excited dye to TiO 2 conduction band.
2021
In this article, we studied a series of dye-sensitized solar cells (DSSCs) type Donor-π-Acceptor involving carbazole as donors and cyanoacrylic acid as acceptors of the electrons. These cells are linked by different π-spacer unit’s, with the aim to develop new organic dyes with high-performance optoelectronic properties. Different units have been introduced in the π-bridge in order to investigate their effects on the structural and optoelectronic properties of the studied compounds, as well as their adsorbed compounds-titanium dioxide (TiO2) semi-conductor. We evaluated and assessed the important relevant parameters that influence the performance of photovoltaic cell to measure their involvement in the short-circuit photocurrent density (Jsc). Using Density Functional Theory (DFT) and Time-Dependent-BHandHLYP, the geometrical and optoelectronics properties have been predicted theoretically. The results obtained indicate that introducing the oxazole (S5) and thiazole (S6) molecules i...
Journal of Molecular Structure, 2019
The metal free organic sensitizers for dye sensitized solar cells (DSSC) have been developed from carbazole donor based on D-π-A architecture. From the structural modifications, the optical and electronic properties of the dyes were tuned. In the present investigation series of carbazole donor based metal free dyes were studied using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The optimized geometry, frontier molecular orbitals, energy levels and electronic absorption spectra were studied. The natural bond orbital analysis (NBO) gives the net electron transfer from the donor to acceptor. The electrochemical properties and light harvesting efficiency of the designed dye sensitizers were calculated. The π spacer increase induced the absorption peak and red shift was noted. The life time was increased by adding phenyl ring in the donor side. Based on theoretical calculations designed dye molecules are evaluated for DSSC application.
2018
In this paper, we have designed several novel organic donor-π-acceptor dyes. The electron acceptor group is the 2–cyanoacetic for all dyes; whereas the electron donor is the bridged thienylen-phenylene with varied unit based on a series of X moieties and their influence was analyzed. These dyes were studied by using density functional theory (DFT) and its extensible time dependent DFT (TDDFT). However, the electronic properties (HOMO, LUMO, Gap…) were determined from the most stable conformations obtained from completely optimized structures. The absorption properties (λmax, Eex, f) of these molecules are obtained by TD-B3LYP/6-31G(d) method. Moreover, the open-circuit photovoltage (Voc) and the key parameters in close connection with the short-circuit current density (Jsc), including light-harvesting efficiency (LHE), injection driving force (ΔGinject) were discussed. These properties suggest these dyes as good candidates for use in organic dye-sensitized solar cells
Optical and Quantum Electronics, 2020
Modulation of metal free organic (MFO) molecules become imperative to researchers to obtain low-cost sensitizer for dye sensitized solar cells (DSSCs) purposes. A series of metal free phenothiazine-based (PTZ) organic dyes are designed and optimized as sensitizers for DSSCs application. Their electronic and optical properties were probed using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) approaches. Effects of additional donor unit, π-conjugation bridges, and benzothiadiazole (BTDA) were investigated. Introducing BTDA in the acceptor unit leads to the tailoring of the energy band gap and promotion of charge transfer within donor and anchor groups with increased effective parameters in DSSC efficiency. The addition of diphenylamine, triphenylamine, or hexyloxyphenyl to the PTZ unit increased electron delocalization and enhanced intramolecular charge transfer. Changing π-spacer from phenyl to thiophene has a great effect on the electronic properties and absorption spectra of the dyes. The relationship between light harvesting efficiency (LHE) and chemical hardness (ƞ) shows that structural design that consists of BTDA and thiophene as π-spacer tends most towards excellent performance as dye sensitizers in DSSCs.
Efficient thieno[3,2-a]carbazole-based organic dyes for dye-sensitized solar cells
Tetrahedron, 2015
Dedicated to Professor Emeritus Jiro Tsuji for his outstanding contribution to chemistry of palladiumcatalyzed reactions ABSTRACT A new series of donor-π-acceptor organic dyes based on thieno[3,2-a]carbazole as a new donor moiety, designated as JH-dyes, has been synthesized for dye-sensitized solar cells (DSCs). The photophysical properties and DSC performances of JH-dyes have been characterized. Among the three JH-dyes, a high power conversion efficiency (η) of 8.04% with a short-circuit current (J sc) of 14.08 mA cm-2 and an open-circuit voltage (V oc) of 0.78 V has been achieved for DSC based on JH03 bearing hexyl chains on the terthiophene π-linker. The electrochemical impedance spectra (EIS) and intensity-modulated photovoltage spectroscopy (IMVS) of JH-cells were measured to understand the effect of molecular structure on charge transfer process and electron life time.
Theoretical Chemistry Accounts, 2014
Based on our recent report on a high overall conversion efficiency of the dye namely CCT3A exhibiting 96 % of the standard N719-based cell (Sudyoadsuk et al. in Eur J Org Chem, 23:5051-5063, 2013), a new series of metal-free organic donor-p-acceptor dyes are systematically further designed by an assistance of density functional theory (DFT) and time-dependent DFT (TD-DFT) methods. By taking carbazole-carbazole as a double-donor group and cyanoacrylic acid as an acceptor units, the plinkers have been varied with different transporting moieties to investigate their potential performances in dyesensitized solar cells (DSSCs) and evaluated through optimized geometries, charge distributions, electronic structures, simulated absorption spectra, and free energies of electron injection. The absorption spectrum of CCTA, one of our dyes in CCT3A series, was simulated by five different DFTs with various exchange-correlation functions to validate an appropriate functional prior to being employed as the functional of choice to investigate our new designed dyes. The long-range-corrected TD-CAM-B3LYP is found to provide the best results in predicting the k max close to experimental data. The variation of p-linkers strongly affects the molecular orbital energy levels. The efficiencies of all dyes as sensitizers in DSSCs are also predicted by analyzing the important key parameters (the HOMO-LUMO energy gap (D H-L ), dipole moment change (Dl), distance of charge transfer upon excitation from ground to excited state (D CT ), free energies of injection (DG inject ), and light-harvesting efficiencies). Our results suggest that the two carbazole-carbazole-based dyes containing thieno [3,2-b]thiophene and benzothiadiazole as the p-linker exhibit higher efficiencies than the existing CCTA dye.