Ground-State Electronic Structure in Charge-Transfer Complexes Based on Carbazole and Diarylamine Donors

2011 ◽  
Vol 115 (21) ◽  
pp. 10823-10835 ◽  
Author(s):  
Paul Winget ◽  
Jean-Luc Brédas
Keyword(s):  
Electronic Structure ◽  
Charge Transfer ◽  
Ground State ◽  
Charge Transfer Complexes

Introduction

2003 ◽  
Author(s):  
Toshiaki Enoki ◽  
Morinobu Endo ◽  
Masatsugu Suzuki
Keyword(s):  
Electronic Structure ◽  
Charge Transfer ◽  
Ionization Potential ◽  
Molecular Orbital ◽  
Electron Affinity ◽  
Basic Unit ◽  
Charge Transfer Complexes ◽  
Vacuum Level ◽  
2D System ◽  
Lowest Unoccupied Molecular Orbital

There are two important features in the structure and electronic properties of graphite: a two-dimensional (2D) layered structure and an amphoteric feature (Kelly, 1981). The basic unit of graphite, called graphene is an extreme state of condensed aromatic hydrocarbons with an infinite in-plane dimension, in which an infinite number of benzene hexagon rings are condensed to form a rigid planar sheet, as shown in Figure 1.1. In a graphene sheet, π-electrons form a 2D extended electronic structure. The top of the HOMO (highest occupied molecular orbital) level featured by the bonding π-band touches the bottom of the LUMO (lowest unoccupied molecular orbital) level featured by the π*-antibonding band at the Fermi energy EF, the zero-gap semiconductor state being stabilized as shown in Figure 1.2a. The AB stacking of graphene sheets gives graphite, as shown in Figure 1.3, in which the weak inter-sheet interaction modifies the electronic structure into a semimetallic one having a quasi-2D nature, as shown in Figure 1.2b. Graphite thus features a 2D system from both structural and electronic aspects. The amphoteric feature is characterized by the fact that graphite works not only as an oxidizer but also as a reducer in chemical reactions. This characteristic stems from the zero-gap-semiconductor-type or semimetallic electronic structure, in which the ionization potential and the electron affinity have the same value of 4.6 eV (Kelly, 1981). Here, the ionization potential is defined as the energy required when we take one electron from the top of the bonding π-band to the vacuum level, while the electron affinity is defined as the energy produced by taking an electron from the vacuum level to the bottom of the anti-bonding π*-band. The amphoteric character gives graphite (or graphene) a unique property in the charge transfer reaction with a variety of materials: namely, not only an electron donor but also an electron acceptor gives charge transfer complexes with graphite, as shown in the following reactions: . . .xC + D → D+ C+x. . . . . .(1.1). . . . . .xC + A → C+x A−. . . . . .(1.2). . . where C, D, and A are graphite, donor, and acceptor, respectively.

scholarly journals Efficient two-step photogeneration of long-lived charges in ground-state charge-transfer complexes of conjugated polymer doped with fullerene

2009 ◽  
Vol 11 (33) ◽  
pp. 7324 ◽  
Author(s):  
Artem A. Bakulin ◽  
Sergey A. Zapunidy ◽  
Maxim S. Pshenichnikov ◽  
Paul H.M. van Loosdrecht ◽  
Dmitry Yu. Paraschuk
Keyword(s):  
Charge Transfer ◽  
Ground State ◽  
Conjugated Polymer ◽  
Charge Transfer Complexes ◽  
State Charge

121Sb NMR and SCF-MS-Xα Studies of Quadrupole Interaction and The Electronic Structure of Mixed-Valence Compound, Cs2SbCl6

1996 ◽  
Vol 51 (5-6) ◽  
pp. 672-676 ◽  
Author(s):  
Takahiro Ueda ◽  
Nobuo Nakamura
Keyword(s):  
Electronic Structure ◽  
Charge Transfer ◽  
Ground State ◽  
Mixed Valence ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Nmr Spectrum ◽  
Quadrupole Coupling ◽  
Mixed Valence Compound ◽  
Complex Anions

Cs2SbCl6 is known as a typical mixed-valence compound. It crystallizes into a tetragonal space group I41/amd and contains two different complex anions, Sb(III)Cl3-6 and Sb(V)Cl-6 . The dark blue color of this compound has been considered to originate from a charge transfer between the above two anions. In order to study the electronic structure of these complex anions and the existence of charge transfer between them we measured the 121Sb NMR spectrum and carried out molecular orbital calculations on the electronic states of these anions. The 121Sb NMR spectrum consists of two peaks at 0 and 30 kHz which can be assigned to the central transition of 121Sb in Sb(V)Cl-6 and Sb(III)Cl3-6 , respectively. The line shape analyses of the spectra led to nuclear quadrupole coupling constants of nearly zero for Sb(V)Cl-6 and 4.9 ± 0.5 MHz for Sb(III)Cl3-6 at room temperature. The quadrupole coupling constant of 121Sb(III) decreases steadily on heating. The calculations of the electronic ground state energies of both anions were calculated by the MS-Xα molecular orbital method. The calculated charge-transfer band from the A1g state of Sb(III)Cl3-6 to the A1g state of Sb(V)Cl-6 appears at 610 nm and can account for the experimental electronic spectrum, the calculated quadrupole coupling constant in Sb(III)Cl3-6 however is far larger than the experimental one. The contribution of the charge-transferred state to the ground state is negligible and so the temperature dependence of the quadrupole coupling constant of 121Sb(III) is attributed to an anisotropic thermal expansion of the compound.

scholarly journals Ultrafast Charge Photogeneration Dynamics in Ground-State Charge-Transfer Complexes Based on Conjugated Polymers

2008 ◽  
Vol 112 (44) ◽  
pp. 13730-13737 ◽  
Author(s):  
Artem A. Bakulin ◽  
Dmitry S. Martyanov ◽  
Dmitry Yu. Paraschuk ◽  
Maxim S. Pshenichnikov ◽  
Paul H. M. van Loosdrecht
Keyword(s):  
Charge Transfer ◽  
Conjugated Polymers ◽  
Ground State ◽  
Charge Transfer Complexes ◽  
State Charge

Ground state and excited state charge transfer complexes between electron donors and pyrylium salts

1984 ◽  
Vol 26 (2-3) ◽  
pp. 131-140 ◽  
Author(s):  
V. Wintgens ◽  
J. Pouliquen ◽  
M. Simalty ◽  
J. Kossanyi ◽  
F.K. Justesen ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Ground State ◽  
Electron Donors ◽  
Charge Transfer Complexes ◽  
Pyrylium Salts ◽  
State Charge

scholarly journals Threshold-like complexation of conjugated polymers with small molecule acceptors in solution within the neighbor-effect model

2016 ◽  
Vol 18 (6) ◽  
pp. 4684-4696 ◽  
Author(s):  
Andrey Yu. Sosorev ◽  
Olga D. Parashchuk ◽  
Sergey A. Zapunidi ◽  
Grigoriy S. Kashtanov ◽  
Ilya V. Golovnin ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Conjugated Polymers ◽  
Small Molecule ◽  
Ground State ◽  
Cooperative Effect ◽  
Charge Transfer Complexes ◽  
Effect Model ◽  
Sharp Growth ◽  
Neighbor Effect ◽  
Electronic Ground

A pronounced cooperative effect leading to a sharp growth of charge-transfer complexes (CTCs) in the electronic ground state is observed.

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