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

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.

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

Chemical Science ◽

10.1039/c5sc04954g ◽

2016 ◽

Vol 7 (6) ◽

pp. 3851-3856 ◽

Cited By ~ 55

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).

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

10.26434/chemrxiv.12245537.v1 ◽

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

The mechanistic study of molecular doping of organic semiconductors (OSC) requiresan improved understanding of the role and formation of integer charge transfer complexes(ICTC) on a microscopic level. In the present work we go one crucial step beyondthe simplest scenario of an isolated bi-molecular ICTC and study ICTCs formed ofup 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-benzothiadiazole)](PCPDT-BT) oligomers and up to two CN6-CP molecules. We find that dependingon geometric arrangement, complexes containing two conjugated oligomers and twodopant molecules can show p-type doping with double integer charge transfer, resulting in eithertwo singly doped oligomers or one doubly doped oligomer. Interestingly, compared to an individualoligomer-dopant complex, the resulting in-gap states on the doped oligomers are significantlylowered in energy. Indicating that, already in the relatively small systems studied here, Coulombbinding of the doping-induced positive charge to the counter-ion is reduced which is an elementalstep towards generating mobile charge carriers through molecular doping.

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Microscopic picture of molecular double doping

10.33774/chemrxiv-2021-v9q4z ◽

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.

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

10.26434/chemrxiv.12245537 ◽

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

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P-type molecular doping by charge transfer in halide perovskite

Materials Advances ◽

10.1039/d1ma00160d ◽

2021 ◽

Author(s):

Julie Euvrard ◽

Gunawan Oki ◽

Xinjue Zhong ◽

Steven P. Harvey ◽

Antoine Kahn ◽

...

Keyword(s):

Charge Transfer ◽

Significant Control ◽

Molecular Doping ◽

Halide Perovskite ◽

P Type ◽

Electronic Technologies

Electronic technologies critically rely on the ability to broadly dope the active semiconductor; yet the promising class of halide perovskite semiconductors so far does not allow for significant control over...

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