Mapping the Electronic Structure of Polypyrrole with Image-Based Electrochemical Scanning Tunnelling Spectroscopy

Conducting polymers are versatile semiconductors whose applications cover a wide range of devices. Their versatility is due, in addition to other factors, to properties that can be easily modulated according to the intended application. It is therefore important to study and map the electronic structure of these materials to allow for a better correlation between structure and properties. Electrochemical scanning tunnelling spectroscopy (EC-STS) can be a powerful tool to characterize the electronic structure of the semiconductor electrolyte interface. In this work we have used image-based EC-STS (IB-EC-STS) to describe quantitatively the band structure of an electrochemically deposited polypyrrole (PPy) film. IB-EC-STS located the band edge of the polymer’s valence band (VB) at 0.95 V vs. RHE (-5.33 eV in the absolute potential scale) and the intragap polaron states formed when the polymer is oxidised (doped) at 0.46 V vs. RHE (-4.84 eV in the absolute potential scale). The IB-EC-STS data were cross checked with electrochemical impedance spectroscopy (EIS) and Mott-Schottky analysis of the interfacial capacitance. The DOS spectrum obtained from EIS data is consistent with the STS-deduced location of the VB and the polarons.

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Mapping the Electronic Structure of Polypyrrole with Image-Based Electrochemical Scanning Tunnelling Spectroscopy

10.26434/chemrxiv.13135532 ◽

2020 ◽

Author(s):

Roger Goncalves ◽

Robert S. Paiva ◽

Andres M R Ramirez ◽

Jonathan A Mwanda ◽

Ernesto C. Pereira ◽

...

Keyword(s):

Electronic Structure ◽

Electrochemical Impedance ◽

Wide Range ◽

Scanning Tunnelling ◽

Potential Scale ◽

Electrochemically Deposited ◽

Interfacial Capacitance ◽

The Absolute ◽

Absolute Potential ◽

Scanning Tunnelling Spectroscopy

Conducting polymers are versatile semiconductors whose applications cover a wide range of devices. Their versatility is due, in addition to other factors, to properties that can be easily modulated according to the intended application. It is therefore important to study and map the electronic structure of these materials to allow for a better correlation between structure and properties. Electrochemical scanning tunnelling spectroscopy (EC-STS) can be a powerful tool to characterize the electronic structure of the semiconductor electrolyte interface. In this work we have used image-based EC-STS (IB-EC-STS) to describe quantitatively the band structure of an electrochemically deposited polypyrrole (PPy) film. IB-EC-STS located the band edge of the polymer’s valence band (VB) at 0.95 V vs. RHE (-5.33 eV in the absolute potential scale) and the intragap polaron states formed when the polymer is oxidised (doped) at 0.46 V vs. RHE (-4.84 eV in the absolute potential scale). The IB-EC-STS data were cross checked with electrochemical impedance spectroscopy (EIS) and Mott-Schottky analysis of the interfacial capacitance. The DOS spectrum obtained from EIS data is consistent with the STS-deduced location of the VB and the polarons.

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Scanning tunnelling spectroscopy on the local electronic structure of Gd@C82 peapods

physica status solidi (b) ◽

10.1002/pssb.201000152 ◽

2010 ◽

Vol 247 (11-12) ◽

pp. 3030-3032 ◽

Cited By ~ 1

Author(s):

Kazunori Ohashi ◽

Naoki Imazu ◽

Ryo Kitaura ◽

Hisanori Shinohara

Keyword(s):

Electronic Structure ◽

Scanning Tunnelling ◽

Local Electronic Structure ◽

Scanning Tunnelling Spectroscopy

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The absolute potential scale in solid state electrochemistry

Solid State Ionics ◽

10.1016/s0167-2738(02)00396-x ◽

2002 ◽

Vol 152-153 ◽

pp. 625-639 ◽

Cited By ~ 24

Author(s):

D Tsiplakides

Keyword(s):

Solid State ◽

Solid State Electrochemistry ◽

Potential Scale ◽

The Absolute ◽

Absolute Potential ◽

State Electrochemistry

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Modelling pH and potential in dynamic structures of the water/Pt(111) interface on the atomic scale

Physical Chemistry Chemical Physics ◽

10.1039/c7cp03576d ◽

2017 ◽

Vol 19 (34) ◽

pp. 23505-23514 ◽

Cited By ~ 25

Author(s):

Martin Hangaard Hansen ◽

Anders Nilsson ◽

Jan Rossmeisl

Keyword(s):

Electrode Potential ◽

Atomic Scale ◽

Potential Scale ◽

Work Functions ◽

The Absolute ◽

Absolute Potential ◽

Dynamic Structures ◽

Grand Canonical

Modelling liquid structures averages of water in the interface with Pt(111) as grand canonical averages, that are functions of pH and electrode potential, using work functions as the absolute potential scale.

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Insulators at the ultrathin limit: electronic structure studied by scanning tunnelling microscopy and scanning tunnelling spectroscopy

Journal of Physics Condensed Matter ◽

10.1088/0953-8984/16/4/r02 ◽

2004 ◽

Vol 16 (4) ◽

pp. R49-R81 ◽

Cited By ~ 74

Author(s):

Silvia Schintke ◽

Wolf-Dieter Schneider

Keyword(s):

Electronic Structure ◽

Scanning Tunnelling Microscopy ◽

Scanning Tunnelling ◽

Tunnelling Microscopy ◽

Scanning Tunnelling Spectroscopy

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Electronic structure of single DNA molecules resolved by transverse scanning tunnelling spectroscopy

Nature Materials ◽

10.1038/nmat2060 ◽

2007 ◽

Vol 7 (1) ◽

pp. 68-74 ◽

Cited By ~ 113

Author(s):

Errez Shapir ◽

Hezy Cohen ◽

Arrigo Calzolari ◽

Carlo Cavazzoni ◽

Dmitry A. Ryndyk ◽

...

Keyword(s):

Electronic Structure ◽

Dna Molecules ◽

Single Dna Molecules ◽

Scanning Tunnelling ◽

Scanning Tunnelling Spectroscopy

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Performance of Electronic Structure Methods for the Description of Hückel-Möbius Interconversions in Extended π-Systems

10.26434/chemrxiv.10564115 ◽

2019 ◽

Author(s):

Tatiana Woller ◽

Ambar Banerjee ◽

Nitai Sylvetsky ◽

Xavier Deraet ◽

Frank De Proft ◽

...

Keyword(s):

Electronic Structure ◽

Basis Set ◽

Dft Methods ◽

Molecular Switching ◽

Wide Range ◽

Electronic Structure Methods ◽

Explicitly Correlated ◽

Relative Errors ◽

The Stability ◽

Basis Set Expansion

Expanded porphyrins provide a versatile route to molecular switching devices due to their ability to shift between several π-conjugation topologies encoding distinct properties. Taking into account its size and huge conformational flexibility, DFT remains the workhorse for modeling such extended macrocycles. Nevertheless, the stability of Hückel and Möbius conformers depends on a complex interplay of different factors, such as hydrogen bonding, p···p stacking, steric effects, ring strain and electron delocalization. As a consequence, the selection of an exchange-correlation functional for describing the energy profile of topological switches is very difficult. For these reasons, we have examined the performance of a variety of wavefunction methods and density functionals for describing the thermochemistry and kinetics of topology interconversions across a wide range of macrocycles. Especially for hexa- and heptaphyrins, the Möbius structures have a pronouncedly stronger degree of static correlation than the Hückel and figure-eight structures, and as a result the relative energies of singly-twisted structures are a challenging test for electronic structure methods. Comparison of limited orbital space full CI calculations with CCSD(T) calculations within the same active spaces shows that post-CCSD(T) correlation contributions to relative energies are very minor. At the same time, relative energies are weakly sensitive to further basis set expansion, as proven by the minor energy differences between MP2/cc-pVDZ and explicitly correlated MP2-F12/cc-pVDZ-F12 calculations. Hence, our CCSD(T) reference values are reasonably well-converged in both 1-particle and n-particle spaces. While conventional MP2 and MP3 yield very poor results, SCS-MP2 and particularly SOS-MP2 and SCS-MP3 agree to better than 1 kcal mol-1 with the CCSD(T) relative energies. Regarding DFT methods, only M06-2X provides relative errors close to chemical accuracy with a RMSD of 1.2 kcal mol-1. While the original DSD-PBEP86 double hybrid performs fairly poorly for these extended p-systems, the errors drop down to 2 kcal mol-1 for the revised revDSD-PBEP86-NL, again showing that same-spin MP2-like correlation has a detrimental impact on performance like the SOS-MP2 results.

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Single-charge transport through hybrid core–shell Au-ZnS quantum dots: a comprehensive analysis from a modified energy structure

Nanoscale ◽

10.1039/d0nr06883g ◽

2021 ◽

Author(s):

Tuhin Shuvra Basu ◽

Simon Diesch ◽

Ryoma Hayakawa ◽

Yutaka Wakayama ◽

Elke Scheer

Keyword(s):

Quantum Dots ◽

Electronic Structure ◽

Carrier Transport ◽

Comprehensive Analysis ◽

Energy Structure ◽

Core Shell ◽

Single Charge ◽

Scanning Tunnelling Microscope ◽

Single Carrier ◽

Scanning Tunnelling

We examined the modified electronic structure and single-carrier transport of individual hybrid core–shell metal–semiconductor Au-ZnS quantum dots using a scanning tunnelling microscope.

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