scholarly journals Tuning the Optoelectronic Properties of Cross Conjugated Small Molecules Using Benzodithiophene As a Core Unit With Favorable Photovoltaic Parameters

2021 ◽  
Author(s):  
Sana Majeed ◽  
Shafiq Ur Rehman ◽  
Anjum Zia ◽  
Javed Iqbal
Keyword(s):  
Density Functional ◽  
Photovoltaic Cells ◽  
Transition Density ◽  
Reorganization Energy ◽  
Hole Mobility ◽  
Open Circuit ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Conjugated Molecules ◽  
Basic Parameters

Abstract In a recent study, cross conjugated molecules (BDT-C1 to BDT-C6) based on Benzo [1,2-b:4,5-bʹ] (BDT) as core units linked with different acceptor moieties are designed for encouraging photovoltaic applications. The optoelectronic study has been conducted by density functional theory (DFT) at B3LYP 6-31G (d, p) basis set combination by equating them with recently reported cross conjugated reference (BDT-CR) molecule and to study basic parameters such as frontier molecular orbital , density of states, reorganization energy, maximum absorption, dipole moment, transition density matrix (TDM) and open-circuit voltage (VOC). Six new cross conjugated molecules (BDT-C1 to BDT-C6) with modified acceptor moieties are designed to evaluate their photophysical behavior in photovoltaic cells and the optoelectronic analysis of designed molecules indicates that among all cross conjugated molecules, BDT-C3 molecule exhibited the lowest bandgap value (1.83 eV) and broad absorption (747 nm) spectrum in dichloromethane (DCM) due to extended conjugation in molecule than BDT-CR. TDM results reveal the easy dissociation of exciton due to the transfer of electron density in a diagonal direction from donor to acceptor moieties. The lowest value of electron mobility (0.0030 eV) and hole mobility (0.0027 eV) of BDT-C4 indicates its excellent electron and hole transfer behavior. The newly architecture molecule BDT-C5 displayed the highest VOC value of 1.75 eV concerning PC61BM. All above-mentioned outcomes reflects that our newly architecture cross conjugated molecules are suitable applicants for photovoltaic cells and can exhibit wonderful results in the quest of power conversion efficiency (PCE).

scholarly journals Exploration of promising optical and electronic properties of (non-polymer) small donor molecules for organic solar cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Khalid ◽  
Muhammad Usman Khan ◽  
Saeed Ahmed ◽  
Zahid Shafiq ◽  
Mohammed Mujahid Alam ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solar Cells ◽  
Organic Solar Cells ◽  
Density Functional ◽  
Reorganization Energy ◽  
Energy Difference ◽  
Open Circuit ◽  
Frontier Molecular Orbital ◽  
Functional Theory ◽  
Td Dft

AbstractNon-fullerene based organic compounds are considered promising materials for the fabrication of modern photovoltaic materials. Non-fullerene-based organic solar cells comprise of good photochemical and thermal stability along with longer device lifetimes as compared to fullerene-based compounds. Five new non-fullerene donor molecules were designed keeping in view the excellent donor properties of 3-bis(4-(2-ethylhexyl)-thiophen-2-yl)-5,7-bis(2ethylhexyl) benzo[1,2-:4,5-c′]-dithiophene-4,8-dione thiophene-alkoxy benzene-thiophene indenedione (BDD-IN) by end-capped modifications. Photovoltaic and electronic characteristics of studied molecules were determined by employing density functional theory (DFT) and time dependent density functional theory (TD-DFT). Subsequently, obtained results were compared with the reference molecule BDD-IN. The designed molecules presented lower energy difference (ΔΕ) in the range of 2.17–2.39 eV in comparison to BDD-IN (= 2.72 eV). Moreover, insight from the frontier molecular orbital (FMO) analysis disclosed that central acceptors are responsible for the charge transformation. The designed molecules were found with higher λmax values and lower transition energies than BDD-IN molecule due to stronger end-capped acceptors. Open circuit voltage (Voc) was observed in the higher range (1.54–1.78 V) in accordance with HOMOdonor–LUMOPC61BM by designed compounds when compared with BDD-IN (1.28 V). Similarly, lower reorganization energy values were exhibited by the designed compounds in the range of λe(0.00285–0.00370 Eh) and λh(0.00847–0.00802 Eh) than BDD-IN [λe(0.00700 Eh) and λh(0.00889 Eh)]. These measurements show that the designed compounds are promising candidates for incorporation into solar cell devices, which would benefit from better hole and electron mobility.

scholarly journals Theoretical modeling of Ring-Locked S-shaped acceptor molecules for High-Performance Organic Solar Cells

2021 ◽  
Author(s):  
Malik Muhammad Asif Iqbal ◽  
Muhammad Mehboob ◽  
Dr. Riaz Hussain ◽  
Talha Hassan ◽  
Muhammad Ramzan Saeed Ashraf Janjua
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
High Performance ◽  
Density Functional ◽  
Transition Density ◽  
Reorganization Energy ◽  
Open Circuit ◽  
Matrix Analysis ◽  
Conversion Efficiencies ◽  
Acceptor Molecules

The introduction of a bridge element to covalently ring-lock the neighboring aryl or heteroaryl groups connected by a single bond has led to a variety of fascinating multifused ladder-type structures. Here, we have designed a new series of 2H-pyran containing tetracyclic dithienocyclopentapyran compounds (MMA1 to MMA3). Long conjugation at end-capped of designed systems enhances the power conversion efficiencies of non-fullerene-containing organic solar cells. Different geometric parameters of designed systems have been examined through density functional theory and time-dependent density function theory. Designed molecules expressed high absorption maxima values with a reduced energy bandgap. Open circuit voltage along with transition density matrix analysis recommended that charge transfer occurs from lower energy orbitals to higher energy orbitals. Reorganization energy analysis also suggested high charge mobility occurs from donor polymer to acceptor molecules. Results of all parameters advocated that designed molecules are potential candidates for high-performance organic solar cells.

Theoretical investigation on tautomerism and NLO properties of Salicylideneaniline derivatives

2021 ◽  
Author(s):  
N. Daho ◽  
N. Benhalima ◽  
F. KHELFAOUI ◽  
O. SADOUKI ◽  
M. Elkeurti ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Intramolecular Proton Transfer ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Visible Absorption ◽  
Charge Delocalization ◽  
Intramolecular Hydrogen

In this work, a comprehensive investigation of the salicylideneaniline derivatives is carried out using density functional theory to determine their linear and non-linear optical properties. Geometry optimizations, for gas and solvent phases, of the tautomers (enol and keto forms) are calculated using B3LYP levels with 6–31G (d,p) basis set . An intramolecular proton transfer, for 1SA-E and 2SA-E, is performed by a PES scan process at the B3LYP/6-31G (d,p) level. The optical properties are determined and show that they have extremely high nonlinear optical properties. In addition, the RDG analysis, MEP, and gap energy are calculated. The low energy gap value indicates the possibility of intramolecular charge transfer. The frontier molecular orbital calculations clearly show the inverse relationship of HOMO–LUMO gap with the first-order hyperpolarizability (β = 59.6471 × 10-30 esu), confirming that the salicylideneaniline derivatives can be used as attractive future NLO materials. Therefore, the reactive sites are predicted using MEP and the visible absorption maxima are analyzed using a theoretical UV–Vis spectrum. Natural bond orbitals are used to investigate the stability, charge delocalization, and intramolecular hydrogen bond.

scholarly journals Theoretical Study of Solvent Effects on the Electronic and Thermodynamic Properties of Tetrathiafulvalene (TTF) Molecule Based on DFT

2021 ◽  
pp. 42-54
Author(s):  
Rabiu Nuhu Muhammad ◽  
N. M. Mahraz ◽  
A. S Gidado ◽  
A. Musa
Keyword(s):  
Thermodynamic Properties ◽  
Bond Length ◽  
Density Functional ◽  
Theoretical Study ◽  
Energy Gap ◽  
Basis Set ◽  
Basis Sets ◽  
Frontier Molecular Orbital ◽  
Orbital Energy ◽  
Chemical Hardness

Tetrathiafulvalene () is an organosulfur compound used in the production of molecular devices such as switches, sensors, nonlinear optical devices and rectifiers. In this work, a theoretical study on the effects of solvent on TTF molecule was investigated and reported based on Density Functional Theory (DFT) as implemented in Gaussian 03 package using B3LYP/6-31++G(d,p) basis set. Different solvents were introduced as a bridge to investigate their effects on the electronic structure. The HUMO, LUMO, energy gap, global chemical index, thermodynamic properties, NLO and DOS analysis of the TTF molecule in order to determine the reactivity and stability of the molecule were obtained. The results obtained showed that the solvents have effects on the electronic and non-linear-optical properties of the molecule. The optimized bond length revealed that the molecule has strong bond in gas phase with smallest bond length of about 1.0834Å than in the rest of the solvents. It was observed that the molecule is more stable in acetonitrile with HOMO-LUMO gap and chemical hardness of 3.6373eV and 1.8187eV respectively. This indicates that the energy gap and chemical hardness of TTF molecule increases with the increase in polarity and dielectric constant of the solvents. The computed results agreed with the results in the literature. The thermodynamics and NLO properties calculation also indicated that TTF molecule has highest value of specific heat capacity (Cv), total dipole moment () and first order hyperpolarizability () in acetonitrile, while acetone has the highest value of entropy and toluene has a slightly higher value of zero point vibrational energy (ZPVE) than the rest of the solvents. The results show that careful selection of the solvents and basis sets can tune the frontier molecular orbital energy gap of the molecule and can be used for molecular device applications.

scholarly journals Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

2017 ◽  
Vol 13 ◽  
pp. 863-873 ◽  
Author(s):  
Vinila N Viswanathan ◽  
Arun D Rao ◽  
Upendra K Pandey ◽  
Arul Varman Kesavan ◽  
Praveen C Ramamurthy
Keyword(s):  
Molecular Orbital ◽  
Architectural Design ◽  
Density Functional ◽  
Short Circuit ◽  
Energy Levels ◽  
Photovoltaic Performance ◽  
Hole Mobility ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Lowest Unoccupied Molecular Orbital

A series of low band gap, planar conjugated polymers, P1 (PFDTBT), P2 (PFDTDFBT) and P3 (PFDTTBT), based on fluorene and benzothiadiazole, was synthesized. The effect of fluorine substitution and fused aromatic spacers on the optoelectronic and photovoltaic performance was studied. The polymer, derived from dithienylated benzothiodiazole and fluorene, P1, exhibited a highest occupied molecular orbital (HOMO) energy level at −5.48 eV. Density functional theory (DFT) studies as well as experimental measurements suggested that upon substitution of the acceptor with fluorine, both the HOMO and lowest unoccupied molecular orbital (LUMO) energy levels of the resulting polymer, P2, were lowered, leading to a higher open circuit voltage and short circuit current with an overall improvement of more than 110% for the photovoltaic devices. Moreover, a decrease in the torsion angle between the units was also observed for the fluorinated polymer P2 due to the enhanced electrostatic interaction between the fluorine substituents and sulfur atoms, leading to a high hole mobility. The use of a fused π-bridge in polymer P3 for the enhancement of the planarity as compared to the P1 backbone was also studied. This enhanced planarity led to the highest observed mobility among the reported three polymers as well as to an improvement in the device efficiency by more than 40% for P3.

scholarly journals Structure, electronic properties, NBO, NLO and chemi-cal reactivity of bis (1, 4-dithiafulvalene) derivatives: functional density theory study

2017 ◽  
Vol 6 (1) ◽  
pp. 18
Author(s):  
Tahar Abbaz ◽  
Amel Bendjeddou ◽  
Didier Villemin
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Computational Study ◽  
Molecular Geometry ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Reactivity Descriptors ◽  
Nlo Property ◽  
Functional Density Theory ◽  
Nucleophilic Reactivity

In this work, through computational study based on density functional theory (DFT/B3LYP) using basis set 6-31G (d,p) a number of global and local reactivity descriptors for a series of molecules containing a TTF function which are bis (1,4-dithiafulvalene) derivatives. They were computed to predict the reactivity and the reactive sites on the molecules. The molecular geometry and the electronic properties in the ground state such as frontier molecular orbital (HOMO and LUMO), ionization potential (I) and electron affinity (A) were investigated to get a better insight of the molecular properties. Molecular electrostatic potential (MEP) for all compounds were determined to check their electrophilic or nucleophilic reactivity. Fukui index, polarizability, hyperpolarizability, second order NLO property and natural bond orbital (NBO) analyses have also employed to determine the reactivity of bis (1,4-dithiafulvalene) derivatives.

scholarly journals Density functional theory calculations and Hirshfeld surface analysis of propyl-para-hydroxybenzoate (PHB) for optoelectronic application

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
V. Mohankumar ◽  
N. Karunagaran ◽  
M. Senthil Pandian ◽  
P. Ramasamy
Keyword(s):  
Charge Transfer ◽  
Surface Analysis ◽  
Density Functional ◽  
Hirshfeld Surface ◽  
Basis Set ◽  
Hirshfeld Surface Analysis ◽  
Frontier Molecular Orbital ◽  
Mulliken Charge ◽  
Charge Analysis ◽  
Orbital Analysis

AbstractThe geometries, electrostatic potential, Mulliken charge analysis, Natural Bond Orbital analysis and polarizabilities of propyl-para-hydroxybenzoate were calculated using B3LYP functional with 6-311++G(d,p) basis set. The calculated geometries are well matched with the experimental values. The Mullliken atomic charge analysis shows that the eventual charges are contained in the molecule. The NBO analysis explains the intramolecular charge transfer in the PHB molecule. The bonding features of the molecule were analyzed with the aid of Hirshfeld surface analysis. The frontier molecular orbital analysis showed the charge transfer obtained within the molecule. The calculated hyperpolarizability of the PHB molecule was 6.977E−30 esu and it was 8.9 times that of standard urea molecule.

scholarly journals Crystal Structure, Hirshfeld Surface and Frontier Molecular Orbital Analyses of N-[2-(trifluoromethyl)phenyl]succinamic Acid

2020 ◽  
Vol 32 (12) ◽  
pp. 3179-3185
Author(s):  
P.A. Suchetan ◽  
S. Naveen ◽  
N.K. Lokanath ◽  
P. Krishna Murthy ◽  
M.V. Deepa Urs
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Orbital ◽  
Density Functional ◽  
Hirshfeld Surface ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Reactivity Descriptors ◽  
Succinamic Acid ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

The ortho-CF3 substituent and the N-H bond are in syn-conformation in N-[2-(trifluoromethyl)phenyl]succinamic acid. In amide and acid functionalities, the carbonyl groups are directed in opposite directions to each other and their related-CH2 groups. syn-Conformation is observed for the acid functionality, where the carbonyl C=O and hydroxyl O-H bonds are directed in the same direction. Three planar fragments comprise of the molecule: aromatic ring (A), core portion -Carm-N(H)-C(=O)-C(H2)-C(H2)(B) and -C(H2)-C(=O)-OH(C). The dihedral angle between a pair of fragments being 48.6(4)º (A and B), 81.6 (4)º (B and C) and 70.5 (5)º (A and C). N-H•••O hydrogen bonds bind the molecules forming C(4) chains in the crystal, and the neighbouring anti-parallel chains are bound by O-H•••O hydrogen bonds resulting in a chair shaped ribbon of one-dimensional nature. The Hirshfeld surface study was carried out, including fingerprint plots. Studies have shown that the interactions with O•••H/H•••O (27.4%), H•••H (27.3%) and H•••F/F•••H (20.2%) substantially added to the surface. Theoretically, the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and various global reactivity descriptors were also computed by the density functional theory (DFT/B3LYP) approach with a 6-311G(d, p) basis set in the ground state on the geometrically optimized structure in the gas phase.

scholarly journals Designing and Theoretical study of fluorinated small molecule donor materials for organic solar cells

2021 ◽  
Author(s):  
Usama Mubashar ◽  
Afifa Farhat ◽  
Rasheed Ahmad Khera ◽  
Rabia Saleem ◽  
Javed IQBAL
Keyword(s):  
Band Gap ◽  
Organic Solar Cells ◽  
Density Functional ◽  
Optical Band Gap ◽  
Transition Density ◽  
Reorganization Energy ◽  
Binding Energies ◽  
Fullerene Derivative ◽  
Photovoltaic Properties ◽  
Enhanced Absorption

Abstract A recently synthesized photoactive donor named fluorinated thienyl substituted benzodithiophene (DRTB-FT), modified with four novel end capped acceptor molecules, have been investigated through different electrical, quantum and spectrochemical techniques for their enhanced electro-optical and photovoltaic properties. DRTB-FT was connected to 2-methylenemalononitrile (D-1), 2-methylene-3-oxobutanenitrile (D-2), 2-(2-methylene-3-oxo-2,3-dihydro-1H-inden-1-ylidene) malonitrile (D-3) and 3-methyl-5methylene-2-thioxothiazolidin-4-one (D-4) as terminal acceptor moieties. The architectural D-1 and D-3 molecules owe reduced optical band gap of 2.45 and 2.28 eV benefited from A-D-A configuration and have broaden maximum absorption band (λmax) at 617 and 602 nm in polar organic solvent (chloroform). Reduced optical band gap set the ease for enhanced absorption. Reorganization energy of electron (λe) of D-3 molecule (0.00397 eV) was smaller amongst all which disclosed its greater mobility of conducting electrons (ICT). Larger values of dipole moment (µ) of D-1(5.939 Debye) and D-3 (3.661 Debye) molecules in comparison to R indicated greater solubilities of the targeted molecules. Among the tailored molecules, D-3 showed lowest binding energy of 0.25 eV in solvent phase and 0.08 eV in gaseous phase. The voltaic strength of designed molecules was examined with respect to fullerene derivative (PC61BM) which exposed that D-1 is the best choice for achieving higher PCE. TDM (transition density matrix), DOS (density of states) analysis and binding energies all were estimated at MPW1PW91/6-31G (d, p) level of DFT (density functional theory).

scholarly journals Exploration of efficient electron acceptors for organic solar cells: rational design of indacenodithiophene based non-fullerene compounds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Khalid ◽  
Muhammad Usman Khan ◽  
Eisha-tul -Razia ◽  
Zahid Shafiq ◽  
Mohammed Mujahid Alam ◽  
...  
Keyword(s):  
Organic Solar Cells ◽  
Rational Design ◽  
Open Circuit Voltage ◽  
Quantum Chemical Study ◽  
Reorganization Energy ◽  
Open Circuit ◽  
Frontier Molecular Orbital ◽  
Photovoltaic Properties ◽  
Energy Devices ◽  
End Group

AbstractThe global need for renewable sources of energy has compelled researchers to explore new sources and improve the efficiency of the existing technologies. Solar energy is considered to be one of the best options to resolve climate and energy crises because of its long-term stability and pollution free energy production. Herein, we have synthesized a small acceptor compound (TPDR) and have utilized for rational designing of non-fullerene chromophores (TPD1–TPD6) using end-capped manipulation in A2–A1–D–A1–A2 configuration. The quantum chemical study (DFT/TD-DFT) was used to characterize the effect of end group redistribution through frontier molecular orbital (FMO), optical absorption, reorganization energy, open circuit voltage (Voc), photovoltaic properties and intermolecular charge transfer for the designed compounds. FMO data exhibited that TPD5 had the least ΔE (1.71 eV) with highest maximum absorption (λmax) among all compounds due to the four cyano groups as the end-capped acceptor moieties. The reorganization energies of TPD1–TPD6 hinted at credible electron transportation due to the lower values of λe than λh. Furthermore, open circuit voltage (Voc) values showed similar amplitude for all compounds including parent chromophore, except TPD4 and TPD5 compounds. These designed compounds with unique end group acceptors have the potential to be used as novel fabrication materials for energy devices.

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