scholarly journals Effect of Electronic Acceptor Segments on Photophysical Properties of Low-Band-Gap Ambipolar Polymers

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Yuanzuo Li ◽  
Jingang Cui ◽  
Jianing Zhao ◽  
Jinglin Liu ◽  
Peng Song ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Photophysical Properties ◽  
Energy Levels ◽  
Quantum Chemistry Calculation ◽  
Difference Density ◽  
Charge Difference Density ◽  
Chemistry Calculation ◽  
Donor Acceptor ◽  
The Relationship

Stimulated by a recent experimental report, charge transfer and photophysical properties of donor-acceptor ambipolar polymer were studied with the quantum chemistry calculation and the developed 3D charge difference density method. The effects of electronic acceptor strength on the structure, energy levels, electron density distribution, ionization potentials, and electron affinities were also obtained to estimate the transporting ability of hole and electron. With the developed 3D charge difference density, one visualizes the charge transfer process, distinguishes the role of molecular units, and finds the relationship between the role of DPP and excitation energy for the three polymers during photo-excitation.

scholarly journals The role of L/W in the solar radiation for Saharian cities

2019 ◽  
Vol 91 ◽  
pp. 05006
Author(s):  
Rami Qaoud ◽  
Alkama Djamal
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Energy Levels ◽  
Direct Solar Radiation ◽  
Test Field ◽  
Natural Lighting ◽  
The Difference ◽  
The Impact ◽  
The Relationship

The urban fabric of the desert cities is based on the principle of reducing the impact of urban canyons on direct solar radiation. Here comes this research, which is based on a comparative study of the periods of direct solarisation and values of the solar energy of urban canyons via two urban fabrics that have different building densities, where the ratio between L/W is different. In order to obtain the real values of the solar energy (thermal, lighting), the test field was examined every two hours, each three consecutive days. The measurement stations are positioned by the three types of the relationship between L/W, (L≥2w, L=w, L≤0.5w). According to the results, we noticed and recorded the difference in the periods of direct solarization between the types of urban engineering canyons, reaching 6 hours a day, the difference in thermal values of air, reaching 4 °C, and the difference in periods of direct natural lighting, reaching 6 hours. It should be noted that the role of the relationship between L/W is to protect the urban canyons by reducing the impact of direct solar radiation on urban canyons, providing longer hours of shading, and reducing solar energy levels (thermal, lighting) at the urban canyons. This research is classified under the research axis (the studies of external spaces in the urban environment according to the bioclimatic approach and geographic approach). But this research aims to focus on the tracking and studying the distribution of the solar radiation - thermal radiation and lighting radiation - in different types of street canyons by comparing the study of the direct solarization periods of each type and the quantity of solar energy collected during the solarization periods.

On the Relationship Between Donor/Acceptor Interface Energy Levels and Open-Circuit Voltages

2017 ◽  
Vol 3 (8) ◽  
pp. 1700115 ◽  
Author(s):  
Peicheng Li ◽  
Weiji Hong ◽  
Yiying Li ◽  
Grayson Ingram ◽  
Zheng-Hong Lu
Keyword(s):  
Energy Levels ◽  
Interface Energy ◽  
Open Circuit ◽  
Donor Acceptor ◽  
The Relationship ◽  
Open Circuit Voltages

A FIRST PRINCIPLE ANALYSIS ON THE STRUCTURAL AND PHOTO-INDUCED CHARGE TRANSFER IN RUTHENIUM COMPLEXES OF HEXAAZATRIPHENYLENE

2012 ◽  
Vol 11 (04) ◽  
pp. 895-905 ◽  
Author(s):  
SHA-SHA LIU ◽  
XIAO-XIA LIU ◽  
KANG QIU ◽  
PENG SONG
Keyword(s):  
Charge Transfer ◽  
Quantum Chemical ◽  
Absorption Maximum ◽  
Frontier Molecular Orbital ◽  
First Principle ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Difference Density ◽  
Charge Difference Density ◽  
Induced Charge

Three complexes [ Ru ( CN )4( HAT )]2-( HAT = hexaazatriphenylene ;[ Ru 1]2-), [{ Ru ( CN )4}2 (μ2- HAT )]4-([ Ru 2]4-) and [{ Ru ( CN )4}3(μ3- HAT )]6-([ Ru 3]6-) for supramolecular assemblies are investigated by quantum-chemical calculations. Due to symmetry of complexes, the energy level differences are 2.014 eV and 2.019 eV for [ Ru 2]4- and [ Ru 3]6- complex, which are about 0.4 eV larger than that for [ Ru 1]2- complex. The absorption maximum for [ Ru 1]2- complex in water is at 375.8 nm. Coordination of the second and third Ru(II) center to produce [ Ru 2]4- and [ Ru 3]6- result in a red-shift of this strongest absorption to 453.4 nm and 468.1 nm, respectively. Absorption maximum of three complexes belong to MLCT transitions, which are revealed by frontier molecular orbital theory and charge difference density method.

Synthesis of a new W-type of functional polymer for improving intermolecular charge transfer processes at donor/acceptor interfaces

2019 ◽  
Vol 31 (5) ◽  
pp. 521-527 ◽  
Author(s):  
Yun-Fan Zhang ◽  
Fawen Wu
Keyword(s):  
Charge Transfer ◽  
Energy Gap ◽  
Energy Levels ◽  
Coupling Reaction ◽  
Photocurrent Density ◽  
Orbital Energy ◽  
Functional Polymer ◽  
Suzuki Coupling Reaction ◽  
Donor Acceptor ◽  
Lowest Unoccupied Molecular Orbital

Optimizing charge transfer (CT) processes at donor/acceptor interfaces is an important subject to improving photocurrent density. Geometries of functional polymers play important roles in design of new types of polymers, which were used as electron donor to improve effective separation of electron-hole pairs at donor/acceptor interfaces. In this article, a novel W-type of polymer, poly(1-[4-(9-(2-ethylhexyl)carbazole-3-yl)]phenylazo-2-phenylazoacenaphthylene), was synthesized by a Suzuki coupling reaction for improving interaction between polymers and electron acceptors to enhance intermolecular CT. Geometry of combination of the polymer and C60 shows that main-chain of the polymer could sufficiently touch C60 derivatives. The polymer exhibited a broadband light absorption at the wavelength range from 250 to 650 nm. Ultraviolet–visible spectra and cyclic voltammetry curve suggest that the highest occupied, lowest unoccupied molecular orbital energy levels, and energy gap values are −5.09, −3.18 and 1.91 eV. Fluorescence quenching experiments shows that 99.9% of emission fluorescence of the polymer was quenched by added C60. Therefore, excited electrons at the polymer would be completely transferred to C60 molecules. This article suggests a new W-type functional polymer for improving intermolecular CT processes at donor/acceptor interfaces.

scholarly journals Charge transfer excitons in a donor–acceptor amphidynamic crystal: the role of dipole orientational order

2020 ◽  
Vol 7 (11) ◽  
pp. 2951-2958
Author(s):  
Joshua W. R. Macdonald ◽  
Giacomo Piana ◽  
Massimiliano Comin ◽  
Elizabeth von Hauff ◽  
Gabriele Kociok-Köhn ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Large Amplitude ◽  
Orientational Order ◽  
Molecular Solids ◽  
Electrical Characteristics ◽  
Large Amplitude Motions ◽  
Donor Acceptor ◽  
Charge Transfer Excitons

Large amplitude motions in molecular solids are responsible for anomalous electrical characteristics in amphidynamic crystals. Here we explore the implications for charge transfer excitons photophysics.

“Hot or cold”: how do charge transfer states at the donor–acceptor interface of an organic solar cell dissociate?

2015 ◽  
Vol 17 (43) ◽  
pp. 28451-28462 ◽  
Author(s):  
Heinz Bässler ◽  
Anna Köhler
Keyword(s):  
Charge Transfer ◽  
Solar Cell ◽  
Organic Semiconductors ◽  
Organic Solar Cell ◽  
Excess Energy ◽  
Donor Acceptor ◽  
Photogeneration Of Charges

This perspective discusses concepts to understand efficient photogeneration of charges in organic semiconductors, with particular emphasis on the role of excess energy.

Density functional study on electric structure and optical properties in Na-doped 3C-SiC

2019 ◽  
Vol 33 (24) ◽  
pp. 1950288 ◽  
Author(s):  
Xuefeng Lu ◽  
Jianhua Luo ◽  
Panfeng Yang ◽  
Tingting Zhao ◽  
Junqiang Ren ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Energy Levels ◽  
Functional Study ◽  
Na Doping ◽  
Difference Density ◽  
Density Maps ◽  
Charge Difference Density ◽  
Electric Structure ◽  
Energy Formula

Structural stability along with the electronic and the optical properties of intrinsic 3C-SiC, [Formula: see text] and [Formula: see text] are studied by the first-principles calculations. [Formula: see text] system possesses the most considerate stability with lowest binding energy [Formula: see text] and formation energy [Formula: see text] compared to [Formula: see text]. It is observed that the non-filled impurity energy levels in the vicinity of the Fermi level can subsequently give rise to an enhancement of electrical conductivity of 3C-SiC. Through the analysis of charge difference density maps, it is found that covalence of bonds between the Na atom and nearby C atom reduces in varying degrees. In different concentrations of Na doping systems, especially for the supercell of [Formula: see text], the real and imaginary parts of the dielectric constant are visibly added in the energy range of 0–0.5 eV, demonstrating that the dielectric loss property of the 3C-SiC is improved evidently. These features confirm that the Na-doped 3C-SiC semiconductor is propitious to the wide application of 3C-SiC in the field of absorbing materials.

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