Electron dynamics in photocatalytic surfaces functionalized with nanomaterials

Abstract

Contents
1 Introduction 1
2 Photoelectron spectroscopy 3
2.1 Basic concepts................................................................................................................. 3
2.2 Angle-resolved photoemission........................................................................................ 5
2.3 Two-photon photoemission ........................................................................................... 7
3 Experimental Setup 9
3.1 ESCA ultra-high vacuum system.................................................................................. 9
3.2 Wet chemistry chamber................................................................................. 10
3.3 WALkiire chamber and laser system............................................................................ 12
4 Carbon Nanodots on TiO2(110) 15
4.1 Carbon Nanodots: Synthesis and Photocycle ............................................................ 15
4.2 Water splitting with CND/TÌO2 .................................................................................. 20
4.3 Properties of T1O2........................................................................................................... 22
4.4 Optical spectroscopy of carbon dots ........................................................................... 26
4.5 Sample preparation........................................................................................................... 28
4.6 Sample characterization................................................................................................. 29
4.6.1 Microscopy........................................................................................................... 29
4.6.2 X-ray photoelectron spectroscopy..................................................................... 32
4.6.3 Electronic structure........................................................................................... 37
4.6.4 Unoccupied states.............................................................................................. 39
4.7 Electron dynamics.................................................. 43
4.7.1 Single color 2PPE.............................................................................................. 43
4.7.2 Two-color 2PPE................................................................................................. 46
4.8 Conclusion ....................................................................................................................... 51
5 Hexagonal boron nitride on Cu(lll) 55
5.1 Material properties and applications........................................................................... 55
5.2 Sample preparation and characterization..................................................................... 57
5.3 Electronic structure ....................................................................................................... 59
5.4 Unoccupied states........................................................................................................... 62
5.5 Conclusion ....................................................................................................................... 67
6 Cuprous oxide thin film intercalated between h-BN/Cu(lll) 69
6.1 Water splitting and the Standard Hydrogen Electrode............................................ 69
6.2 Cuprous oxide (CU2O) properties and applications........................ 71
6.3 Cu(lll) surface oxides.................................................................................................... 72
6.4 Experiments at the Swiss Light Source........................................................................ 74
6.5 Electron Dynamics (Publication).................................................................................. 78
6.6 Additional data analysis................................................................................................. 97
6.6.1 XPS and XPD.................................................................................................... 97
6.6.2 Fitting of time-resolved spectra......................................................................... 99
6.6.3 Coherent Phonons................................................................................................. 103
7 Conclusion and Outlook 109