In this work organic molecules, namely derivatives of BODIPY and poly-para-phenyls are investigated on different metal surfaces by means of LT-STM. These molecule are important for the development of molecular electronics and spintronics. I show that aza-BODIPY molecules form a weak chemical bond with the Au(111) substrate and the molecular structure significantly changes upon adsorption. Due to the low corrugation of the Au(111) surface, diffusion of the molecule is observed for applied bias in excess of ±1 V.
The temperature dependent formation of different molecular nanostructures formed by polyparaphenyls and Au adatoms is discussed. The diffusing Au adatoms act as coordination centers for the cyano groups present on one end of the molecules. The structure of the super molecular assemblies completely changes in a temperature range of only 60 K.
Furthermore, I investigate in this work the hybridization of atomic orbitals within the molecular ligand. The Kondo resonance of a Co atom incorporated into an other aza-BODIPY derivative is investigated in detail on Ag(100). The hybridization of the atomic Co orbital with the organic ligands molecular orbitals is shown by spectroscopy measurements with submolecular resolution. The changing line shape of the Kondo resonance for the molecule-substrate system is discussed.
This data is compared to measurements of Co incorporated in another molecular binding motive and on different metal samples to show the importance of the local environment for molecular materials.:Introduction 1
1 Basic Principles 5
1.1 The Scanning Tunneling Microscope 6
1.2 Theory of STM/STS 8
1.2.1 Scanning Tunneling Microscopy 8
1.2.2 Scanning Tunneling Spectroscopy 12
1.2.3 dI/dV-maps and SPECGRIDs 15
1.3 Lateral Manipulation of Adsorbates 15
1.4 The Kondo Effect 17
1.4.1 Investigation of Kondo Systems by STM 19
2 Experimental Setup 23
2.1 LT-STM and UHV System 24
2.2 Substrates 26
2.2.1 Au(111) 26
2.2.2 Ag(100) 28
2.2.3 Cu(110) 28
2.2.4 Surface Preparation 29
2.3 The Molecules 29
2.3.1 aza-BODIPY 29
2.3.2 6Ph-CN 30
2.3.3 Co-(BiPADI)2, Co-BiPADI, and BiPADI 31
2.3.4 Sample Preparation 32
2.4 Organic Photovoltaics 32
3 Aza-BODIPY on Au(111) 35
3.1 Experimental Results 36
3.1.1 STM Images 36
3.1.2 Spectroscopy 38
3.1.3 Lateral Manipulation 38
3.2 Discussion 39
4 6Ph-CN on Au(111) 43
4.1 Experimental Results 44
4.1.1 STM Images 44
4.1.2 Temperature Dependent Nanostructure Formation 44
4.1.3 Spectroscopy 46
4.2 Discussion 47
5 Co-BiPADI on Ag(100) and Cu(110) 55
5.1 Experimental Results 56
5.1.1 Co-BiPADI on Ag(100) 56
5.1.1.1 STM Images and Identification 56
5.1.1.2 Adsorption Geometry 56
5.1.1.3 Spectroscopy and Kondo Resonance 59
5.1.1.4 Temperature Dependent Measurements 63
5.1.1.5 SPECGRID Measurements and Comparison with Molecular Structure
64
5.1.1.6 Interaction of Several Co-BiPADI Molecules and Related Changes
of Their Kondo Resonances 67
5.1.1.7 Determination of Adsorption Position of Molecules in SPECGRID
Measurements 69
5.1.2 Co-BiPADI on Cu(110) 71
5.1.2.1 STM Images and Identification 71
5.1.2.2 STS Measurements and dI/dV Maps 72
5.2 Discussion 74
6 Co-(BiPADI)2 on Au(111) 81
6.1 Experimental Results 82
6.1.1 STM Images 82
6.1.2 Spectroscopy 82
6.2 Discussion 86
7 Conclusions and Outlook 89
Bibliography 93
List of Publications 101
Acknowledgments 103
A Appendices 105
A.1 Fitting Routine for Kondo STS 105
A.2 Background Subtraction in Kondo STS 107
A.3 MATLAB Fitting Tool fit.m 107
A.4 Import Routine and Fitting Script for SPECGRID Files 111
A.5 Calibration of Piezo Constants from Atomically Resolved Images 112
A.5.1 Au(111) 112
A.5.2 Ag(100) 112
Confirmation 113 / In dieser Arbeit werden organische Moleküle, Derivate von BODIPY und poly-para-Phenyl, auf verschiedenen Metalloberflächen mittels Tief-Temperatur Rastertunnelmikroskopie (LT-STM) untersucht. Diese Moleküle sind wichtig für die Entwicklung von molekularer Elektronik und Spintronik. Ich zeige, dass aza-BODIPY-Moleküle eine schwache chemische Bindung mit dem Au(111)- Substrat eingehen und die molekulare Struktur bei der Adsorption deutlich verändert wird. Wegen der geringen Rauigkeit der Au(111)-Oberfläche wird bereits bei einer angelegten Spannungen über ±1 V die Diffusion der Moleküle beobachtet.
Die temperaturabhängige Bildung verschiedener molekularer Nanostrukturen aus poly-para-Phenyl und frei beweglichen Goldatomen wird diskutiert. Die diffundierenden Goldatome agieren hierbei als Koordinationszentren für die Cyanogruppen am einen Ende der Moleküle. Die Struktur der supramolekularen Anordnungen verändert sich dabei in einem Temperaturbereich von nur 60 K vollkommen.
Außerdem beschäftige ich mich in dieser Arbeit mit der Hybridisierung atomare Orbitale im molekularen Verbund. Die Kondo-Resonanz eine Co-Atoms, welches in einem anderen aza-BODIPY-Derivat gebunden ist, wird detailliert auf der Ag(100)-Oberfläche untersucht. Die Hybridisierung des atomaren Co-Orbitals mit den molekularen Orbitalen des organischen Liganden wird an Hand von Spektroskopiemessungen mit submolekularer Auflösung gezeigt. Die veränderte Form der Kondo-Resonanz für dieses Molekül-Substrat-System wird diskutiert. Diese Daten werden mit Messungen an Co-Atomen in anderen molekularen Bindungsschemen und auf anderen Substraten verglichen um dieWichtigkeit der lokalen Umgebung für molekulare Materialien zu verdeutlichen.:Introduction 1
1 Basic Principles 5
1.1 The Scanning Tunneling Microscope 6
1.2 Theory of STM/STS 8
1.2.1 Scanning Tunneling Microscopy 8
1.2.2 Scanning Tunneling Spectroscopy 12
1.2.3 dI/dV-maps and SPECGRIDs 15
1.3 Lateral Manipulation of Adsorbates 15
1.4 The Kondo Effect 17
1.4.1 Investigation of Kondo Systems by STM 19
2 Experimental Setup 23
2.1 LT-STM and UHV System 24
2.2 Substrates 26
2.2.1 Au(111) 26
2.2.2 Ag(100) 28
2.2.3 Cu(110) 28
2.2.4 Surface Preparation 29
2.3 The Molecules 29
2.3.1 aza-BODIPY 29
2.3.2 6Ph-CN 30
2.3.3 Co-(BiPADI)2, Co-BiPADI, and BiPADI 31
2.3.4 Sample Preparation 32
2.4 Organic Photovoltaics 32
3 Aza-BODIPY on Au(111) 35
3.1 Experimental Results 36
3.1.1 STM Images 36
3.1.2 Spectroscopy 38
3.1.3 Lateral Manipulation 38
3.2 Discussion 39
4 6Ph-CN on Au(111) 43
4.1 Experimental Results 44
4.1.1 STM Images 44
4.1.2 Temperature Dependent Nanostructure Formation 44
4.1.3 Spectroscopy 46
4.2 Discussion 47
5 Co-BiPADI on Ag(100) and Cu(110) 55
5.1 Experimental Results 56
5.1.1 Co-BiPADI on Ag(100) 56
5.1.1.1 STM Images and Identification 56
5.1.1.2 Adsorption Geometry 56
5.1.1.3 Spectroscopy and Kondo Resonance 59
5.1.1.4 Temperature Dependent Measurements 63
5.1.1.5 SPECGRID Measurements and Comparison with Molecular Structure
64
5.1.1.6 Interaction of Several Co-BiPADI Molecules and Related Changes
of Their Kondo Resonances 67
5.1.1.7 Determination of Adsorption Position of Molecules in SPECGRID
Measurements 69
5.1.2 Co-BiPADI on Cu(110) 71
5.1.2.1 STM Images and Identification 71
5.1.2.2 STS Measurements and dI/dV Maps 72
5.2 Discussion 74
6 Co-(BiPADI)2 on Au(111) 81
6.1 Experimental Results 82
6.1.1 STM Images 82
6.1.2 Spectroscopy 82
6.2 Discussion 86
7 Conclusions and Outlook 89
Bibliography 93
List of Publications 101
Acknowledgments 103
A Appendices 105
A.1 Fitting Routine for Kondo STS 105
A.2 Background Subtraction in Kondo STS 107
A.3 MATLAB Fitting Tool fit.m 107
A.4 Import Routine and Fitting Script for SPECGRID Files 111
A.5 Calibration of Piezo Constants from Atomically Resolved Images 112
A.5.1 Au(111) 112
A.5.2 Ag(100) 112
Confirmation 113
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:29418 |
| Date | 26 February 2016 |
| Creators | Meyer, Jörg |
| Contributors | Moresco, Francesca, Cuniberti, Gianaurelio, Wiesmann, Hans Peter, Technische Universität Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
Page generated in 0.0022 seconds