Electronic Structure and Dynamics at Organic Donor/Acceptor Interfaces

MRS Bulletin ◽  
2010 ◽  
Vol 35 (6) ◽  
pp. 443-448 ◽  
Author(s):  
Xiaoyang Zhu ◽  
Antoine Kahn
Keyword(s):  
Electronic Structure ◽  
Charge Separation ◽  
High Energy ◽  
Electronic Energy ◽  
Molecular Orbitals ◽  
Separation Process ◽  
Energy Gain ◽  
Donor Acceptor ◽  
The Difference ◽  
A Charge

AbstractWe present our understanding of the electronic energy landscape and dynamics of charge separation at organic donor/acceptor interfaces. The organic/organic interface serves as a valuable point of reference and plays an important role in emerging electronic and optoelectronic applications, particularly organic photovoltaics (OPVs). The key issue on electronic structure at organic donor/acceptor interfaces is the difference in the lowest unoccupied molecular orbitals or that in the highest occupied molecular orbitals. This difference represents an energy gain needed to overcome the exciton binding energy in a charge-separation process in OPV. A sufficiently large energy gain favors the formation of charge transfer (CT) states that are energetically close to the charge-separation state. At an organic donor/acceptor interface in an OPV device, these high-energy CT states, also called hot CT excitons, are necessary intermediates in a successful charge-separation process.

New development of photoinduced electron-transfer catalytic systems

2007 ◽  
Vol 79 (6) ◽  
pp. 981-991 ◽  
Author(s):  
Shunichi Fukuzumi
Keyword(s):  
Electron Transfer ◽  
Organic Solar Cells ◽  
Charge Separation ◽  
Energy Charge ◽  
High Energy ◽  
Significant Loss ◽  
Catalytic Systems ◽  
Molecular Electron ◽  
New Development ◽  
Donor Acceptor

As an alternative to conventional charge-separation functional molecular models based on multi-step long-range electron transfer (ET) within redox cascades, simple donor-acceptor dyads have been developed to attain a long-lived and high-energy charge-separated (CS) state without significant loss of excitation energy. In particular, a simple molecular electron donor-acceptor dyad, 9-mesityl-10-methylacridinium ion (Acr+-Mes), is capable of fast charge separation but extremely slow charge recombination. Such a simple molecular dyad has significant advantages with regard to synthetic feasibility, providing a variety of applications for photoinduced ET catalytic systems, including efficient photocatalytic systems for the solar energy conversion and construction of organic solar cells.

The electronic structure and spin-charge separation of one-dimensional SrCuO2

2019 ◽  
Vol 33 (02) ◽  
pp. 1950006
Author(s):  
Huaisong Zhao ◽  
Jiasheng Qian ◽  
Sheng Xu ◽  
Feng Yuan
Keyword(s):  
Electronic Structure ◽  
Charge Separation ◽  
Energy Region ◽  
Doping Concentration ◽  
High Energy ◽  
Intermediate Energy ◽  
Low Energy ◽  
One Dimensional ◽  
High Energy Peak ◽  
Energy Peak

Based on the t-J model and slave-boson theory, we have studied the electronic structure in one-dimensional SrCuO2 by calculating the electron spectrum. Our results show that the electron spectra are mainly composed of three parts in one-dimensional SrCuO2, a sharp low-energy peak, a broad intermediate-energy peak and a high-energy peak. The sharp low-energy peak corresponds to the main band (MB) while the broad intermediate-energy peak and high-energy peak are associated with the shadow band (SB) and high-energy band (HB), respectively. From low-energy to intermediate-energy region, a clear two-peak structure (MB and SB) around the momentum [Formula: see text] appears, and the distance between two peaks decreases along the momentum direction from [Formula: see text] to [Formula: see text], then disappears at the critical momentum point [Formula: see text], leaving a single peak above [Formula: see text]. The electron spectral function in one-dimensional SrCuO2 is also the doping and temperature dependent. In particular, in the very low doping concentration, the HB merges into the MB. However, with the increases of the doping concentration, the HB separates from the MB and moves quickly to the high-binding energy region. The HB and MB are the direct results of the spin-charge separation while SB is the result of strong interaction between charge and spin parts. Therefore, our theoretical result predicts that the HB is more likely to be found at the low doping concentration, and it will be drowned in the background when the doping concentration is larger. Then with the temperature increases, the magnitude of the SB decreases, and it disappears at high temperature.

Electronic Structure of a Single Hydrogen Centre in Magnesium Crystals

1985 ◽  
Vol 40 (5) ◽  
pp. 433-438
Author(s):  
R. Duscher ◽  
J. K. Maichle
Keyword(s):  
Electronic Structure ◽  
Density Distribution ◽  
Electron Density Distribution ◽  
Energy Difference ◽  
Electronic Energy ◽  
Hexagonal Structure ◽  
Metal Crystal ◽  
Nearest Neighbours ◽  
The Difference ◽  
Radial Electron Density Distribution

In the present work, the problem “hydrogen storage in metals” is treated with the aid of the so-called New Tamm-Dancoff (NTD) procedure. We employ this method in lowest approximation for the evaluation of the electronic energy difference eigenvalue between a metal crystal with and without hydrogen centre. As an example we use Magnesium with hexagonal structure. For this system we calculate the difference eigenvalue with dependence on the displacement of the nearest neighbours and next nearest neighbours of the hydrogen centre, respectively. Finally we calculate the radial electron density distribution in the environment of the proton.

From charge-transfer to a charge-separated state: a perspective from the real-time TDDFT excitonic dynamics

2014 ◽  
Vol 16 (44) ◽  
pp. 24457-24465 ◽  
Author(s):  
Alessio Petrone ◽  
David B. Lingerfelt ◽  
Nadia Rega ◽  
Xiaosong Li
Keyword(s):  
Charge Transfer ◽  
Block Copolymers ◽  
Real Time ◽  
Charge Separation ◽  
The Real ◽  
Separation Mechanisms ◽  
Electronic Dynamics ◽  
Donor Acceptor ◽  
A Charge

Real-time TDDFT electronic dynamics for studying the charge separation mechanisms in donor/acceptor block copolymers.

Electronic Structure Benchmark Calculations of Inorganic and Biochemical Carboxylation Reactions

2018 ◽  
Author(s):  
Oscar A. Douglas-Gallardo ◽  
David A. Sáez ◽  
Stefan Vogt-Geisse ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Electronic Structure ◽  
Chemical Reactions ◽  
Density Functional ◽  
Correlation Energy ◽  
Electronic Energy ◽  
Basis Sets ◽  
Electronic Correlation ◽  
Correct Description ◽  
Carbon Dioxide Co2 ◽  
High Level

<div><div><div><p>Carboxylation reactions represent a very special class of chemical reactions that is characterized by the presence of a carbon dioxide (CO2) molecule as reactive species within its global chemical equation. These reactions work as fundamental gear to accomplish the CO2 fixation and thus to build up more complex molecules through different technological and biochemical processes. In this context, a correct description of the CO2 electronic structure turns out to be crucial to study the chemical and electronic properties associated with this kind of reactions. Here, a sys- tematic study of CO2 electronic structure and its contribution to different carboxylation reaction electronic energies has been carried out by means of several high-level ab-initio post-Hartree Fock (post-HF) and Density Functional Theory (DFT) calculations for a set of biochemistry and inorganic systems. We have found that for a correct description of the CO2 electronic correlation energy it is necessary to include post-CCSD(T) contributions (beyond the gold standard). These high-order excitations are required to properly describe the interactions of the four π-electrons as- sociated with the two degenerated π-molecular orbitals of the CO2 molecule. Likewise, our results show that in some reactions it is possible to obtain accurate reaction electronic energy values with computationally less demanding methods when the error in the electronic correlation energy com- pensates between reactants and products. Furthermore, the provided post-HF reference values allowed to validate different DFT exchange-correlation functionals combined with different basis sets for chemical reactions that are relevant in biochemical CO2 fixing enzymes.</p></div></div></div>

scholarly journals Ion tracks in silicon formed by much lower energy deposition than the track formation threshold

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
H. Amekura ◽  
M. Toulemonde ◽  
K. Narumi ◽  
R. Li ◽  
A. Chiba ◽  
...  
Keyword(s):  
Nuclear Energy ◽  
Energy Deposition ◽  
Ion Irradiation ◽  
High Energy ◽  
Electronic Energy ◽  
Synergy Effect ◽  
Ion Tracks ◽  
Track Formation ◽  
Low Energies ◽  
High Energy Ions

AbstractDamaged regions of cylindrical shapes called ion tracks, typically in nano-meters wide and tens micro-meters long, are formed along the ion trajectories in many insulators, when high energy ions in the electronic stopping regime are injected. In most cases, the ion tracks were assumed as consequences of dense electronic energy deposition from the high energy ions, except some cases where the synergy effect with the nuclear energy deposition plays an important role. In crystalline Si (c-Si), no tracks have been observed with any monomer ions up to GeV. Tracks are formed in c-Si under 40 MeV fullerene (C60) cluster ion irradiation, which provides much higher energy deposition than monomer ions. The track diameter decreases with decreasing the ion energy until they disappear at an extrapolated value of ~ 17 MeV. However, here we report the track formation of 10 nm in diameter under C60 ion irradiation of 6 MeV, i.e., much lower than the extrapolated threshold. The diameters of 10 nm were comparable to those under 40 MeV C60 irradiation. Furthermore, the tracks formed by 6 MeV C60 irradiation consisted of damaged crystalline, while those formed by 40 MeV C60 irradiation were amorphous. The track formation was observed down to 1 MeV and probably lower with decreasing the track diameters. The track lengths were much shorter than those expected from the drop of Se below the threshold. These track formations at such low energies cannot be explained by the conventional purely electronic energy deposition mechanism, indicating another origin, e.g., the synergy effect between the electronic and nuclear energy depositions, or dual transitions of transient melting and boiling.

Influence of metal phthalocyanine molecular orientation on charge separation at organic donor/acceptor interface

2021 ◽  
Author(s):  
Heeseon Lim ◽  
Sena Yang ◽  
Sang-Hoon Lee ◽  
Jung-Yong Lee ◽  
Yeunhee Lee ◽  
...  
Keyword(s):  
Solar Cell ◽  
Charge Separation ◽  
Molecular Orientation ◽  
Organic Solar Cell ◽  
Metal Phthalocyanine ◽  
Dipole Orientation ◽  
Highly Efficient ◽  
Donor Acceptor

To achieve a highly efficient organic solar cell (OPVs), control of molecular orientation is one of prime important factors, for interfacial dipole orientation and energy offset at donor/acceptor (D/A) interface...

scholarly journals Efficient Inverted Solar Cells Using Benzotriazole-Based Small Molecule and Polymers

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 393
Author(s):  
Ja Eun Lee ◽  
Yoon Kim ◽  
Yang Ho Na ◽  
Nam Seob Baek ◽  
Jae Woong Jung ◽  
...  
Keyword(s):  
Solar Cell ◽  
Conjugated Polymers ◽  
Power Conversion ◽  
High Energy ◽  
Photovoltaic Properties ◽  
Device Structures ◽  
Donor Acceptor ◽  
Medium Band ◽  
Inverted Solar Cell ◽  
Conventional Device

We synthesized medium-band-gap donor-acceptor (D-A) -type conjugated polymers (PBTZCZ-L and PBTZCZ-H) consisting of a benzotriazole building block as an acceptor and a carbazole unit as a donor. In comparison with the polymers, a small conjugated molecule (BTZCZ-2) was developed, and its structural, thermal, optical, and photovoltaic properties were investigated. The power conversion efficiency (PCE) of the BTZCZ-2-based solar cell devices was less than 0.5%, considerably lower than those of polymer-based devices with conventional device structures. However, inverted solar cell devices configured with glass/ITO/ZnO:PEIE/BTZCZ-2:PC71BM/MoO3/Ag showed a tremendously improved efficiency (PCE: 5.05%, Jsc: 9.95 mA/cm2, Voc: 0.89 V, and FF: 57.0%). We believe that this is attributed to high energy transfer and excellent film morphologies.

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