scholarly journals Molecular Controlling the Transport Properties for Benzothiadiazole-Based Hole Transport Materials

2018 ◽  
Vol 8 (9) ◽  
pp. 1461 ◽  
Author(s):  
Qian Liu ◽  
Xiaochen Lin ◽  
Xinlan Cao ◽  
Peng Song ◽  
Fengcai Ma ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Perovskite Solar Cells ◽  
Hole Mobility ◽  
Hole Transport ◽  
Core Structure ◽  
Level Energy ◽  
Functional Theory ◽  
The Core ◽  
Molecular Stability

Three experimental hole transport materials containing fluorine-substituted benzothiadiazole-based organic molecules (Jy5–Jy7) have been studied to explore the relationship between photoelectric performances and the core structures of hole transport materials (HTM). By employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT), it was found that the substitution of the hydrogen atom by fluorine atom in the core structure can significantly boost the hole mobility; and the replacement of core structure from electron-withdrawing group to electron-donating group has strong influence on the increment of LUMO level energy, ability to preventing electron-backflow, molecular stability and oscillator strength of HTM molecules. We hope our investigation can provide theoretical guidance to reasonably optimize HTM molecules for perovskite solar cells.

scholarly journals Density Functional Theory Investigation of Carbon Dots as Hole-transport Material in Perovskite Solar Cells

ChemPhysChem ◽  
2018 ◽  
Vol 19 (22) ◽  
pp. 3018-3023 ◽  
Author(s):  
Sri Kasi Matta ◽  
Chunmei Zhang ◽  
Anthony P. O'Mullane ◽  
Aijun Du
Keyword(s):  
Density Functional Theory ◽  
Solar Cells ◽  
Carbon Dots ◽  
Density Functional ◽  
Perovskite Solar Cells ◽  
Hole Transport ◽  
Functional Theory

STRUCTURES, ABSORPTION SPECTRA, AND ELECTRONIC PROPERTIES OF POLYFLUORENE AND ITS DERIVATIVES: A THEORETICAL STUDY

2006 ◽  
Vol 05 (03) ◽  
pp. 595-608 ◽  
Author(s):  
KRIENGSAK SRIWICHITKAMOL ◽  
SONGWUT SURAMITR ◽  
POTJAMAN POOLMEE ◽  
SUPA HANNONGBUA
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Level Energy ◽  
Excitation Energies ◽  
Lumo Energy ◽  
Functional Theory ◽  
Local Energy Minimum ◽  
Pi Systems ◽  
Homo Lumo

The structural and energetic properties of polyfluorene and its derivatives were investigated, using quantum chemical calculations. Conformational analysis of bifluorene was performed by using ab initio (HF/6-31G* and MP2/6-31G*) and density functional theory (B3LYP/6-31G*) calculations. The results showed that the local energy minimum of bifluorene lies between the coplanar and perpendicular conformation, and the B3LYP/6-31G* calculations led to the overestimation of the stability of the planar pi systems. The HOMO-LUMO energy differences of fluorene oligomers and its derivatives — 9,9-dihexylfluorene (DHPF), 9,9-dioctylfluorene (PFO), and bis(2-ethylhexyl)fluorene (BEHPF) — were calculated at the B3LYP/6-31G* level. Energy gaps and effective conjugation lengths of the corresponding polymers were obtained by extrapolating HOMO-LUMO energy differences and the lowest excitation energies to infinite chain length. The lowest excitation energies and the maximum absorption wavelength of polyfluorene were also performed, employing the time-dependent density functional theory (TDDFT) and ZINDO methods. The extrapolations, based on TDDFT and ZINDO calculations, agree well with experimental results. These theoretical methods can be useful for the design of new polymeric structures with a reducing energy gap.

A comparative study of structural, electronic and optical properties based on metal-doped methylammonium lead halidesviafirst-principles calculations

2019 ◽  
Vol 43 (24) ◽  
pp. 9453-9457 ◽  
Author(s):  
Diwen Liu ◽  
Huijuan Jing ◽  
Rongjian Sa ◽  
Kechen Wu
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Solar Cells ◽  
Comparative Study ◽  
Density Functional ◽  
Perovskite Solar Cells ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Metal Doped

To reduce the toxicity of Pb in perovskite solar cells, the structural stabilities, and electronic and optical properties of the mixed perovskites MAPb0.75B0.25I3(B = Mg, Ca, Sr, and Ba) were predicted using density functional theory.

scholarly journals Solvent Free Three-Component Synthesis of 2,4,5-trisubstituted-1H-pyrrol-3-ol-type Compounds from L-tryptophan: DFT-B3LYP Calculations for the Reaction Mechanism and 3H-pyrrol-3-one↔1H-pyrrol-3-ol Tautomeric Equilibrium

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4402
Author(s):  
Diego Quiroga ◽  
Lili Dahiana Becerra ◽  
Ericsson Coy-Barrera
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Potassium Hydroxide ◽  
Density Functional ◽  
Tautomeric Equilibrium ◽  
Solvent Free ◽  
Functional Theory ◽  
Solvent Free Conditions ◽  
Molecular Stability ◽  
B3lyp Calculations

In this paper, we describe the solvent-free three-component synthesis of 2,4,5-trisubstituted-1H-pyrrol-3-ol-type compounds from L-tryptophan. The first step of the synthetic methodology involved the esterification of L-tryptophan in excellent yields (93–98%). Equimolar mixtures of alkyl 2-aminoesters, 1,3-dicarbonyl compounds, and potassium hydroxide (0.1 eq.) were heated under solvent-free conditions. The title compounds were obtained in moderate to good yields (45%–81%). Density functional theory using “Becke, 3-parameter, Lee–Yang–Parr” correlational functional (DFT-B3LYP) calculations were performed to understand the molecular stability of the synthesized compounds and the tautomeric equilibrium from 3H-pyrrol-3-one type intermediates to 1H-pyrrol-3-ol type aromatized rings.

Density functional theory is straying from the path toward the exact functional

Science ◽  
2017 ◽  
Vol 355 (6320) ◽  
pp. 49-52 ◽  
Author(s):  
Michael G. Medvedev ◽  
Ivan S. Bushmarinov ◽  
Jianwei Sun ◽  
John P. Perdew ◽  
Konstantin A. Lyssenko
Keyword(s):  
Density Functional Theory ◽  
Density Distribution ◽  
Ground State ◽  
Electron Density Distribution ◽  
Density Functional ◽  
Electron System ◽  
The Other ◽  
Functional Theory ◽  
The Core ◽  
Exact Density

The theorems at the core of density functional theory (DFT) state that the energy of a many-electron system in its ground state is fully defined by its electron density distribution. This connection is made via the exact functional for the energy, which minimizes at the exact density. For years, DFT development focused on energies, implicitly assuming that functionals producing better energies become better approximations of the exact functional. We examined the other side of the coin: the energy-minimizing electron densities for atomic species, as produced by 128 historical and modern DFT functionals. We found that these densities became closer to the exact ones, reflecting theoretical advances, until the early 2000s, when this trend was reversed by unconstrained functionals sacrificing physical rigor for the flexibility of empirical fitting.

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