Molecular Orientation and Emission Characteristics of Ir Complexes and Exciplex in Organic Thin Films (eBook)

Chang-Ki Moon (Autor)

eBook Download: PDF

2019 | 1st ed. 2019
XXIX, 76 Seiten
Springer Singapore (Verlag)
978-981-13-6055-8 (ISBN)

Infos

This thesis considers molecular orientation in thin films and introduces an optical model describing this orientation as applied to organic light-emitting diodes (OLEDs). It also describes the electronic structure of intermolecular charge transfer excitons correlated to molecular orientation in solids.

It has long been known that molecular orientation influences the electrical and optical properties of molecular films. One notable example is in liquid crystals where rigid rod or disk shaped molecules are commonly used. Understanding the origin of the molecular orientation and its control by surface treatment and electric field resulted in the development of liquid crystal displays. The same thing has happened in organic electronics, and considerable effort has been devoted to understanding and controlling molecular orientation in solid films to improve charge carrier mobility and light absorption, ultimately to improve the performance of organic solar cells and thin film transistors.

In contrast, less attention has been paid to molecular orientation and its influence on the characteristics of OLEDs, probably because of the use of amorphous films rather than micro-crystalline films, and it is only in recent years that some molecular films are known to have preferred orientation.  This thesis addresses this topic, focusing on OLEDs, describing the origin and control of the orientation of phosphorescent Ir complexes possessing spherical shape rather than rod or disk shape, the simulation of the optical characteristics of OLEDs influenced by preferred molecular orientation, and finally the orientation of intermolecular charge transfer excitons and its correlation to electronic structures in thin films.

Dr. Chang-Ki Moon received the 'Best PhD Theses Award in 2017' in the Materials Science and Engineering department at SNU in December 2017, and the 'Best Paper Award' of Schrodinger's 2017 Excellence in Materials Science Applications Publication Contest in Schrodinger Inc. in February 15, 2018.  

Inhalt

Supervisor’s Foreword 6
Abstract 8
List of Publications 11
1st Author 11
Other Publications 11
List of Presentations 14
List of Patents 16
Acknowledgements 17
Contents 18
List of Figures 20
List of Tables 27
1 Introduction 28
1.1 Molecular Orientation in Organic Electronics 28
1.1.1 History 28
1.1.2 Importance of the Molecular Orientation 28
1.1.3 Estimation of Molecular Orientations 31
1.2 Optical Models of OLEDs 32
1.3 Iridium Complex 36
1.4 Exciplex 37
1.5 Outline of the Thesis 38
References 40
2 Modeling of the Dipole Radiation in an Anisotropic Microcavity 43
2.1 Introduction 43
2.2 Theoretical Background 44
2.2.1 Dipole Radiation in a Birefringent Medium 44
2.2.2 Efficiency of OLEDs with a Birefringent Emissive Layer 48
2.2.3 Far-Field Radiation 49
2.2.4 Experimental 49
2.3 Results and Discussion 51
2.3.1 Optical Birefringence and the Dipole Orientation 51
2.3.2 Emission Spectra of OLEDs 52
2.3.3 Efficiency of OLEDs 53
2.3.4 Conclusion 54
2.3.5 Appendix 54
References 56
3 The Orientation of Ir Complexes Doped in Organic Amorphous Layers 59
3.1 Influence of Host Materials on the Emitting Dipole Orientation of Ir Complexes 59
3.1.1 Introduction 59
3.1.2 Results and Discussion 60
3.1.3 Conclusion 65
3.2 Unraveling the Orientation of Ir Complexes via Vacuum Deposition Simulation 65
3.2.1 Introduction 65
3.2.2 Results 66
3.2.3 Discussion 72
3.2.4 Conclusion 79
3.2.5 Methods 81
References 83
4 Analysis of the Electronic Structure and Emission Process of Exciplex in Solids 85
4.1 Introduction 85
4.2 Results and Discussion 86
References 95
5 Summary and Conclusion 98
Curriculum Vitae 99

Produkt-Details

• Erscheint lt. Verlag: 29.1.2019
• Reihe/Serie: Springer Theses
• Reihe/Serie: Springer Theses
• Zusatzinfo: XXIX, 76 p. 37 illus., 32 illus. in color.
• Verlagsort: Singapore
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Chemie ► Physikalische Chemie
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Atom- / Kern- / Molekularphysik
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Elektrodynamik
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Festkörperphysik
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Optik
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Theoretische Physik
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• Themenwelt: Technik ► Maschinenbau
• Schlagworte: amorphous films • inter-molecular CT excitons • molecular orientation • organic light emitting diodes • Organic light-emitting diodes • phosphorescent Ir complexes
• ISBN-10: 981-13-6055-3 / 9811360553
• ISBN-13: 978-981-13-6055-8 / 9789811360558