Strategies for the Formation of Covalently Bonded Nano- Networks on Metal Surfaces through Amine Reactions. A thesis for the degree of PHILOSOPHIAE DOCTOR Presented to DUBLIN CITY UNIVERSITY Ollscoil Chathair Bhaile Átha Cliath by Hooi Ling Lee, M.Sc., B. App. Sci.(Hons) School of Physical Sciences Dublin City University Research Supervisor: Dr. A. A. Cafolla External Examiner: Prof. Andrew Evans Internal Examiner: Prof. Greg Hughes May 2012 Declaration I hereby certify that this material, which I now submit for assessment on the programme of study leading to the award of Doctor of Philosophy is entirely my own work, that I have exercised reasonable care to ensure that the work is original, and does not to the best of my knowledge breach any law of copyright, and has not been taken from the work of others save and to the extent that such work has been cited and acknowledged within the text of my work. ------------------------------- Hooi Ling Lee ID No: 58125361 April, 2012. ii Acknowledgements First of all, I wish to convey my heartfelt gratitude to my Ph.D supervisor, Dr. Tony Cafolla for his patience and guidance throughout my doctorate study. I am thankful to my colleagues in my laboratory particularly Dr. John P. Cuniffe, Mr. John P. Beggan, Ms. Catherine Doyle, Ms. Nina Berner and Mr. Thomas Carpy. It has been a wonderful experience working with all of you. I also wish to thank academicians and staff support in Dublin City University especially School of Physical Sciences for their assistance. My deepest appreciation is also dedicated to all my collaborators who have contributed enormously in my research work. I am truly honoured to have had the opportunity to work with the following collaborators who are specialised in their own field: 1. Prof. Louis Porte, Dr. Luca Giovanelli, Dr. Mathieu Abel, Dr. Mathieu Koudia, Dr. Sylvain Clair from IM2NP-CNRS, Aix-Marseille Université, Marseille, France. 2. Dr. Corinne Dufaure from ENSIACET/CIRIMAT, Toulouse, France. 3. Dr. Zheshen Li from The Institute for Storage Rings Facilities (ISA), Aarhus, Denmark. 4. Dr. Alexei B. Preobrajenski from MAX Lab, University of Lund, Sweden. To all my friends who know me, thank you for your friendships and care. Last but not least, thank you to my family especially my parents in Malaysia. Without their continuous faith, I would never make it until this stage. In short, it has been a very humbling journey. This Ph.D work was funded by Science Foundation Ireland (SFI) under grant number 08/RFP/PHY1366. My synchrotron trip to ISA laboratory was supported by the EU grant. The travelling grant to IM2NP was awarded by Ulysses Grant 2011 from Irish Research Council for Sciences, Engineering and Technology, IRCSET-Embark Initiative. Their financial supports are gratefully acknowledged. Thank you. Terima kasih. Go raibh maith agat. iii For my parents iv Table of Contents Declaration ii Acknowledgements iii Dedication iv Table of Contents v List of Poster Publications ix List of Acronyms x Abstract xi Chapter 1: Introduction and Literature Review. 1.0 Introduction. 1 1.1 Literature Review. 1 1.1.1 Supramolecular Chemistry and Self-Assembly. 1 1.2 Porphyrin and Porphyrin Derivatives. 5 1.2.1 Electronic Properties of Porphyrin and Porphyrin Derivatives. 7 1.3 Motivation 8 1.4 Outline of the Thesis. 8 References. 10 Chapter 2: Methodologies. 2.0 Experimental Methods. 13 2.1 The Ultra High Vacuum (UHV) System. 13 2.2 Scanning Tunneling Microscopy (STM). 14 2.2.1 Basic Operational Principles. 15 2.2.2 Scanning Tunnelling Microscopy: Apparatus. 19 2.2.3 Preparation of STM Tip. 21 2.3 X-ray Photoelectron Spectroscopy (XPS). 22 2.4 Ultraviolet Photoelectron Spectroscopy (UPS). 26 2.5 Synchrotron Radiation Techniques. 28 2.5.1 X-ray Absorption Spectroscopy (XAS). 30 2.6 Low Energy Electron Diffraction (LEED). 31 v 2.7 Metal Surfaces. 35 2.7.1 The (22 x 3) on Au(111) Reconstruction. 35 2.7.2 Cu(111) and Ag(111) Surfaces. 35 2.8 Sample Preparation. 36 References. 37 Chapter 3: The Formation of Surface Supported Covalently Bonded TAPP Networks on Au(111), Ag(111) and Cu(111) Surfaces. 3.0 Introduction. 39 3.1 Experimental. 40 3.2 Results and Discussion. 41 3.2.1 STM of TAPP on Au(111) Surface at Room Temperature (RT). 41 3.2.2 Synchrotron based XPS of TAPP on Au(111) Surface at Room 44 Temperature (RT). 3.2.3 XAS of TAPP on Au(111) Surface at Room Temperature (RT). 47 3.2.4 STM of TAPP on Au(111) Surface at Elevated Temperature. 49 3.2.5 XPS of TAPP on Au(111) Surface at Elevated Temperature. 51 3.2.6 STM of TAPP on Cu(111) Surface at Room Temperature (RT). 52 3.2.7 XPS of TAPP on Cu(111) Surface at Room Temperature (RT). 53 3.2.8 STM of TAPP on Cu(111) Surface at Elevated Temperature. 55 3.2.9 XPS of TAPP on Cu(111) Surface at Elevated Temperature. 56 3.2.10 STM of TAPP Self-assembled on Ag(111) Surface at Room 57 Temperature (RT). 3.2.11 XPS of TAPP on Ag(111) Surface at Room Temperature (RT). 59 3.2.12 STM of TAPP on Ag(111) Surface at Elevated Temperature. 60 3.2.13 XPS of TAPP on Ag(111) Surface at Elevated Temperature. 61 3.3 Summary 62 References 64 Chapter 4: UPS Measurements on TAPP Molecules on Au(111) and Cu(111). 4.0 Introduction. 66 4.1 Experimental. 67 4.2 Results and Discussion 68 vi 4.2.1 d Valence Band Spectra as a Function of Coverage on Au(111). 68 4.2.2 UPS Study of the Polymerisation of TAPP on Au(111). 73 4.2.3 Work Function Measurements of TAPP/Au(111) Interface. 76 4.2.4 Valence Band Spectra as a Function of Coverage on Cu(111). 78 4.2.5 UPS Study of the Polymerisation of TAPP on Cu(111). 81 4.2.6 Work Function Measurements of TAPP/Cu(111) Interface. 83 4.3 Summary. 84 References. 86 Chapter 5: Covalent bonding of TAPP and PTCDA on Au(111) Surface. 5.0 Introduction 88 5.1 Materials and Experimental. 89 5.1.1 3, 4, 9, 10-perylene tetracarboxylic dianhydride (PTCDA). 89 5.1.2 Methodology. 89 5.2 Results and Discussion. 90 5.2.1 STM of PTCDA on Au(111). 90 5.2.2 LEED of PTCDA on Reconstructed Au(111). 93 5.2.3 Synchrotron based XPS of PTCDA on Au(111). 95 5.2.4 XAS of PTCDA on Au(111). 97 5.2.5 STM of the bimolecular TAPP-PTCDA on Au(111) Surface. 99 5.2.6 Synchrotron based XPS of the bimolecular TAPP-PTCDA on 101 Au(111) Surface. 5.2.7 XAS of the bimolecular TAPP-PTCDA on Au(111) Surface. 102 5.3 Summary. 104 References. 105 Chapter 6: STM Studies of TAPB molecules on Noble Metal Surfaces and Covalent bonding of TAPB and PTCDA on Ag(111) Surface. 6.0 Introduction. 107 6.1 Experimental. 109 6.2 Results and Discussion. 110 6.2.1 STM of TAPB on Au(111) at Room Temperature (RT). 110 6.2.2 XPS of TAPB on Au(111) at Room Temperature (RT). 111 vii 6.2.3 STM of TAPB on Au(111) at Elevated Temperature. 112 6.2.4 XPS of TAPB on Au(111) at Elevated Temperature. 116 6.2.5 STM of TAPB on Ag(111) at Room Temperature (RT). 117 6.2.6 XPS of TAPB on Ag(111) at Room Temperature (RT). 118 6.2.7 STM of TAPB on Ag(111) at Elevated Temperature. 119 6.2.8 XPS of TAPB on Ag(111) at Elevated Temperature. 121 6.2.9 STM and LEED Studies of PTCDA on Ag(111). 124 6.2.10 XPS Study of PTCDA on Ag(111). 125 6.2.11 STM of Co-deposited of TAPB and PTCDA on Ag(111). 127 6.2.12 XPS of Co-deposited of TAPB and PTCDA on Ag(111). 134 6.3 Summary. 136 References. 138 Chapter 7: Conclusions and Future Work. 7.1 Conclusions. 140 7.2 Future Work. 143 7.2.1 Research Work with TAPB. 143 7.2.2 Self-assembly and Covalent Reaction of BCPP and PTCDA on 143 Au(111). 7.2.3 Synchrotron Radiation Techniques on TAPB Molecules. 145 7.2.4 Density Functional Theory (DFT) Calculations. 145 7.2.5 Fullerene (C60) and TAPP Molecules Studies on Au(111). 145 References 147 Appendix A – Thermogravimetric Analysis (TGA) Spectrum of TAPP. 148 Appendix B – Thermogravimetric Analysis (TGA) Spectrum of TAPB. 149 viii List of Poster Presentations BOC POSTER COMPETITION The formation of surface supported covalently bonded 5,10,15,20-tetrakis(4- aminophenyl)-porphyrin (TAPP) networks. School of Physical Sciences, Dublin City University, 13th April, 2012. ECOSS28 The formation of surface supported covalently bonded 5,10,15,20-tetrakis(4- aminophenyl)-porphyrin (TAPP) networks. Wroclaw, Poland, 28th August, 2011 – 2nd September, 2011. BOC POSTER COMPETITION The formation of surface supported covalently bonded porphyrin networks through polyimidisation. School of Physical Sciences, Dublin City University, 24th September, 2010. -won 3rd prize in the poster competition. ECOSS27 The formation of surface supported covalently bonded porphyrin networks through polyimidisation. th th Groningen, The Netherlands, 29 August, 2009 – 3 September, 2009. ix List of Acronym. E Pass energy p BE Binding energy EBD Electron beam deposition EDC Energy distribution curve ESCA Electron Spectroscopy for Chemical Analysis FWHM Full width half maximum GI Grazing incidence HOMO Highest occupied molecular orbital hν Photon energy KE Kinetic energy LEED Low energy electron diffraction LUMO Lowest occupied molecular orbital MFP Mean free path ML Monolayer MO Molecular orbital NE Normal emission NI Normal incidence PES Photoelectron spectroscopy PTCDA 3, 4, 9, 10-perylene tetracarboxylic dianhydride RT Room temperature SECO Secondary electrons cut-off STM Scanning tunnelling microscopy STS Scanning tunnelling spectroscopy TAPB 1,3,6-tris(4-aminophenel)benzene TAPP 5,10, 15,20-tetrakis(4-aminophenyl)porphyrin TPP Tetra(4-aminophenyl)porphyrin UHV Ultra high vacuum UPS Ultraviolet photoelectron spectroscopy VB Valence band WF Workfunction XAS X-ray absorption spectroscopy XPS X-ray photoelectron spectroscopy x