scholarly journals Molecular Doping in Multi-Molecule Polymer-Dopant Complexes Shows Reduced Coulomb Binding

2020 ◽  
Author(s):  
Chuanding Dong ◽  
Stefan Schumacher
Keyword(s):  
Charge Transfer ◽  
Organic Semiconductors ◽  
Positive Charge ◽  
Charge Carriers ◽  
Mechanistic Study ◽  
Charge Transfer Complexes ◽  
Mobile Charge ◽  
Molecular Doping ◽  
Gap States ◽  
P Type

<p>The mechanistic study of molecular doping of organic semiconductors (OSC) requires</p><p>an improved understanding of the role and formation of integer charge transfer complexes</p><p>(ICTC) on a microscopic level. In the present work we go one crucial step beyond</p><p>the simplest scenario of an isolated bi-molecular ICTC and study ICTCs formed of</p><p>up to two (poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b,3,4-b”]dithiophene)-alt-4,7-(2,1,3-</p><p>benzothiadiazole)](PCPDT-BT) oligomers and up to two CN6-CP molecules. We find that depending</p><p>on geometric arrangement, complexes containing two conjugated oligomers and two</p><p>dopant molecules can show p-type doping with double integer charge transfer, resulting in either</p><p>two singly doped oligomers or one doubly doped oligomer. Interestingly, compared to an individual</p><p>oligomer-dopant complex, the resulting in-gap states on the doped oligomers are significantly</p><p>lowered in energy. Indicating that, already in the relatively small systems studied here, Coulomb</p><p>binding of the doping-induced positive charge to the counter-ion is reduced which is an elemental</p><p>step towards generating mobile charge carriers through molecular doping.</p>

scholarly journals Molecular Doping in Multi-Molecule Polymer-Dopant Complexes Shows Reduced Coulomb Binding

2020 ◽  
Author(s):  
Chuanding Dong ◽  
Stefan Schumacher
Keyword(s):  
Charge Transfer ◽  
Organic Semiconductors ◽  
Positive Charge ◽  
Charge Carriers ◽  
Mechanistic Study ◽  
Charge Transfer Complexes ◽  
Mobile Charge ◽  
Molecular Doping ◽  
Gap States ◽  
P Type

<p>The mechanistic study of molecular doping of organic semiconductors (OSC) requires</p><p>an improved understanding of the role and formation of integer charge transfer complexes</p><p>(ICTC) on a microscopic level. In the present work we go one crucial step beyond</p><p>the simplest scenario of an isolated bi-molecular ICTC and study ICTCs formed of</p><p>up to two (poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b,3,4-b”]dithiophene)-alt-4,7-(2,1,3-</p><p>benzothiadiazole)](PCPDT-BT) oligomers and up to two CN6-CP molecules. We find that depending</p><p>on geometric arrangement, complexes containing two conjugated oligomers and two</p><p>dopant molecules can show p-type doping with double integer charge transfer, resulting in either</p><p>two singly doped oligomers or one doubly doped oligomer. Interestingly, compared to an individual</p><p>oligomer-dopant complex, the resulting in-gap states on the doped oligomers are significantly</p><p>lowered in energy. Indicating that, already in the relatively small systems studied here, Coulomb</p><p>binding of the doping-induced positive charge to the counter-ion is reduced which is an elemental</p><p>step towards generating mobile charge carriers through molecular doping.</p>

Electronic Conduction in Polymers. III. Electronic Properties of Polypyrrole

1963 ◽  
Vol 16 (6) ◽  
pp. 1090 ◽  
Author(s):  
BA Bolto ◽  
R McNeill ◽  
DE Weiss
Keyword(s):  
Charge Transfer ◽  
Pyrolysis Temperature ◽  
Electron System ◽  
Charge Carriers ◽  
Charge Transfer Complexes ◽  
Spin Resonance ◽  
Broad Signal ◽  
Donor Nitrogen ◽  
P Type ◽  
Narrow Signal

The electron spin resonance absorption and electrical resistivity have been measured under rigorous conditions for a series of polypyrroles prepared over the temperature range 120-500�. When plotted as a function of pyrolysis temperature the resistivity shows a maximum in the region 200-300�. Although the resistivity of the polymers prepared at 120� and 500� is roughly similar, their e.s.r. behaviour is quite different. The low-temperature polymer, containing much complexed iodine, shows a very broad signal arising from an excited state probably associated with a polypyrrole-iodine charge-transfer complex; the high temperature polymer, containing no iodine, shows a strong narrow signal arising from the ground state of the polymer. The changes in conductivity of the polymers following the adsorption of electron acceptor or donor molecules have been measured. It is concluded that, depending on the relative amounts of electron donating or attracting chemisorbed species in relation to the concentration of donor nitrogen atoms in the polypyrrole, the polymer may behave as an intrinsic or extrinsic semiconductor with n- or p-type characteristics. Charge-transfer complexes of strength sufficient to cause partial ionization induce extrinsic behaviour by changing the ratio of the number of electrons to the number of holes. Substituent groups such as the hetero atoms which interact with the π-electron system inductively or through resonance affect only the relative mobility of the charge carriers and induce intrinsic behaviour.

scholarly journals Switching charge-transfer characteristics from p-type to n-type through molecular “doping” (co-crystallization)

2016 ◽  
Vol 7 (6) ◽  
pp. 3851-3856 ◽  
Author(s):  
Jing Zhang ◽  
Peiyang Gu ◽  
Guankui Long ◽  
Rakesh Ganguly ◽  
Yongxin Li ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Type Compound ◽  
Transfer Characteristics ◽  
Type Semiconductor ◽  
Molecular Doping ◽  
P Type

A novel molecule, DTPTP, which originally is a p-type compound, can be switched to an n-type semiconductor through tetracyanoquinodimethane doping (co-crystallization).

scholarly journals Microscopic picture of molecular double doping

2021 ◽  
Author(s):  
Thomas Bathe ◽  
Chuan-Ding Dong ◽  
Stefan Schumacher
Keyword(s):  
Absorption Spectrum ◽  
Charge Transfer ◽  
Density Functional ◽  
Near Infrared ◽  
Infrared Absorption Spectrum ◽  
Functional Theory ◽  
Double Doping ◽  
Molecular Doping ◽  
P Type ◽  
Dopant Molecule

Double doping, in which a single dopant molecule induces two charge carriers in an organic semiconductor (OSC), was recently experimentally observed and promises to enhance the efficiency of molecular doping. Here we present a theoretical investigation of p-type molecular double doping in a CN6-CP:bithiophene–thienothiophene OSC system. Our analysis is based on density functional theory (DFT) calculations for the electronic ground state. In a molecular complex with two OSC oligomers and one CN6-CP dopant molecule we explicitly demonstrate double integer charge transfer and find formation of two individual polarons on the OSC molecules and a di-anion dopant molecule. We show that the vibrational modes and related infrared absorption spectrum of this complex can be traced back to those of the charged dopant and OSC molecules in their isolated forms. The near-infrared optical absorption spectrum calculated by time-dependent DFT shows both features of typical intra-molecular polaron excitations and weak inter-molecular charge transfer excitations associated with the doping-induced polaron states.

Tuning the Carrier Type and Density of Monolayer Tin Selenide via Organic Molecular Doping

2021 ◽  
Author(s):  
Yu Jie Zheng ◽  
Qi Zhang ◽  
Omololu Odunmbaku ◽  
Zeping Ou ◽  
Meng Li ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Organic Molecules ◽  
Single Layer ◽  
Conduction Band Edge ◽  
Shallow Acceptor ◽  
Tin Selenide ◽  
Lowest Unoccupied Molecular Orbital ◽  
Molecular Doping ◽  
P Type ◽  
Highest Occupied Molecular Orbitals

Abstract Utilizing first-principles calculations, charge transfer doping process of single layer tin selenide (SL-SnSe) via the surface adsorption of various organic molecules was investigated. Effective p-type SnSe, with carrier concentration exceeding 3.59×1013 cm-2, was obtained upon adsorption of tetracyanoquinodimethane (TCNQ) or 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-quinodimethane (F4TCNQ) on SL-SnSe due to their lowest unoccupied molecular orbital (LUMO) acting as shallow acceptor states. While we could not obtain effective n-type SnSe through adsorption of tetrathiafulvalene (TTF) or 1,4,5,8-tetrathianaphthalene (TTN) on pristine SnSe due to their highest occupied molecular orbitals (HOMO) being far from the conduction band edge of SnSe, this disadvantageous situation can be amended by the introduction of an external electric field perpendicular to the monolayer surface. It is found that Snvac will facilitate charge transfer from TTF to SnSe through introducing an unoccupied gap state just above the HOMO of TTF, thereby partially compensating for the p-type doping effect of Snvac. Our results show that both effective p-type and n-type SnSe can be obtained and tuned by charge transfer doping, which is necessary to promote its applications in nanoelectronics, thermoelectrics and optoelectronics.

Ultrafast photogeneration and band-like transport of mobile charge carriers in organic semiconductors

2005 ◽  
Author(s):  
O. Ostroverkhova ◽  
D. G. Cooke ◽  
S. Shcherbyna ◽  
R. F. Egerton ◽  
F. A. Hegmann ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Charge Carriers ◽  
Mobile Charge

scholarly journals Long-distance charge transport through DNA. An extended hopping model

2001 ◽  
Vol 73 (3) ◽  
pp. 449-453 ◽  
Author(s):  
Bernd Giese ◽  
Martin Spichty ◽  
Stefan Wessely
Keyword(s):  
Charge Transfer ◽  
Charge Transport ◽  
Positive Charge ◽  
Charge Carriers ◽  
Long Distance ◽  
Transfer Rates ◽  
Trapping Reactions ◽  
Hopping Model

Long-distance transfer of a positive charge through DNA can be described by a hopping model. In double strands where the (A:T)n bridges between the guanines are short (n 3), the charge hops only between guanines, and each hopping step depends strongly upon the guanine to guanine distances. In strands where the (A:T)n sequences between the guanines are rather long (n 4), also the adenines act as charge carriers. To predict the yields of the H2O-trapping products one has to take into account not only the charge-transfer rates but also the rates of H2O-trapping reactions.

Investigating the Relationship Between Atomic Structure and Carrier Depletion at [001] tilt Grain Boundaries in Ybco

1999 ◽  
Vol 574 ◽  
Author(s):  
N. D. Browning ◽  
J. P. Buban
Keyword(s):  
Grain Boundaries ◽  
Structural Unit ◽  
Boundary Plane ◽  
Charge Carriers ◽  
Mobile Charge ◽  
Band Bending ◽  
Donor States ◽  
P Type ◽  
The Relationship ◽  
Theoretical Analyses

AbstractRecent theoretical analyses [1] have suggested that the origin of the reduced Jc at grain boundaries in high-Tc superconductors may be band bending, which results in the depletion of mobile charge carriers at the boundaries. For this to occur in these p-type superconductors there must, by definition, be a high density of localized donor states in the boundary plane. Here we report a “structural unit” analysis of [0011 tilt grain boundaries in YBa2Cu 3O7-δ (YBCO) that indicates there may be a simple structural origin for such localized donor states.

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