臺灣博碩士論文加值系統

有機半導體之電荷傳遞方向與有機分子的排列模式有很大關係，瞭解和控制有機半導體薄膜的成長以及了解其排列模式的機制，進而提升可明顯改善有機太陽能電池元件的光電性質。
此研究當中，我們利用證明以不同襯底基板改變並五苯的排列，其中以石墨烯最為襯底基板形成具高優選方向之有機分子膜。從X-射線繞射光譜分析中證明並五苯分子在石墨烯最為襯底時，由原垂直於基板的排列(001)轉變為平行於基板的排列(022)。而在並五苯拉曼光譜之1158cm-1和分峰1155cm-1位子解釋並五苯與基板間之作用力，以及測量表面自由能進一步探討並五苯蒸鍍在不同襯底基板之成長模式。我們利用空間電荷法量測有機分子膜之電性，也成功地證實在元件電性方面有所提升改善。

In this study, we are reporting the effect of the orientation changes of pentacene with regards to its optical and electrical properties. We demonstrated that deposition of pentacene in different substrates lead to different molecular orientation. Furthermore, this study offers a new avenue of controlling the orientation of organic molecules using graphene as template which hopefully aids the transport direction of carriers in solar cell devices. Based on X-ray diffraction spectrum (XRD) and Raman spectrum have shown the different orientation of pentacene in different substrates. Moreover, we have also correlated the surface energy of the substrates with its subsequent effect on pentacene’s molecular orientation.

Table of Contents

摘　要 i
ABSTRACT ii
誌 謝 iii
Table of Contents iv
List of Tables vii
List of Figures viii
Chapter 1 Introduction 1
1.1 Introduction of Organic Semiconductor 1
1.2 Charge Transport and Molecular Orientation 1
1.3 Motivation 3
Chapter 2 5
Background, Concepts and Literature Review 5
2.1 Organic Materials and Chemical Properties 5
2.1.1 Charge Transport Pathways 6
2.1.2 Application of Organic Based Optoelectronic Device 7
2.2 Orientation of Molecules 8
2.2.1 Controlled Molecular Orientation 9
2.3 Background and Application of Graphene 15
2.3.1 Properties 16
2.3.2 Application 17
2.4 OPV Device Architecture 17
2.4.1 Solar Cell Working Principle 18
2.4.2 Device Performance and Modeling 19
2.4.3 Efficiency Measurement 20
2.4.4 Mobility Measurement – SCLC 21
Chapter 3 Experimental Detail 23
Experimental and Analysis Techniques 23
3.1 Substrate Preparation 24
3.1.1 Cu Foil Substrates Preparation 24
3.1.2 Growth Process of The Graphene Substrate 24
3.1.3 ITO Substrate Preparation 25
3.1.4 ITO-PEDOT:PSS Substrates Preparation 25
3.1.5 Pentacene Thin Film Deposition 26
3.1.6 Hole-only Device Fabrication 28
3.2 Sample Characterization 29
3.2.1 Orientation and Morphology Characterization 29
XRD 29
NEXAFS 30
FE-SEM 32
AFM 32
3.2.2 Intermolecular Interaction of Pentacene Molecules 34
3.2.3 Surface Free Energy of Substrates 35
3.2.4 Electrical Property Measurement 36
Chapter 4 Results and Discussion 38
4.1 Controlled Orientation of Small Molecules 38
4.2 Pentacene Orientation Analysis 38
4.2.1 X-ray Scattering 39
4.2.2 Tilting angle between pentacene and substrates 42
4.3 Study of Intermolecular Interaction in Oriented Pentacene Films 45
4.4 Surface Morphology 48
4.4.1 Growth Mode 49
4.4.2 SEM and AFM 50
4.4.3 Surface Energy 52
4.5 Electrical Properties 54
4.5.1 Hole-only device study 55
4.5.2 Photovoltaic device study 58
Chapter 5 Conclusion 61
Reference 62
Symbol Index 69

1.M. Pope and C. E. Swenberg, Electronic Processes in Organic Crystals and Polymers. 2 ed. 1999: Oxford University Press. p. 337-340.
2.C. W. Tang and S. A. VanSlyke, Organic Electroluminescent Diodes. applied Physics Letters, vol. 12, No. 51, 1987, p. 913-915.
3.C. D. Dimitrakopoulos and P. R. L. Malenfant, Organic Thin Film Transistors for Large Area Electronics. Advanced materials, vol. 14, No. 2, 2002, p. 99-117.
4.J. J. Chiu, C. C. Kei, T. P. Perng, et al., Organic Semiconductor Nanowires for Field Emission. Advanced Materials, vol. 15, No. 16, 2003, p. 1361-1364.
5.L. Li, W. Hu, H. Fuchs, et al., Controlling Molecular Packing for Charge Transport in Organic Thin Films. Advanced Energy Materials, vol. 1, No. 2, 2011, p. 188-193.
6.A. Ojala, A. Petersen, A. Fuchs, et al., Merocyanine/C60 Planar Heterojunction Solar Cells: Effect of Dye Orientation on Exciton Dissociation and Solar Cell Performance. Advanced Functional Materials, vol. 22, No. 1, 2012, p. 86-96.
7.S. D. Wang, X. Dong, C. S. Lee, et al., Orderly Growth of Copper Phthalocyanine on Highly Oriented Pyrolytic Graphite (HOPG) at High Substrate Temperatures. The Journal of Physical Chemistry B, vol. 108, No. 5, 2004, p. 1529-1532.
8.K. Xiao, W. Deng, J. K. Keum, et al., Surface-induced Orientation Control of CuPc Molecules for The Epitaxial Growth of Highly Ordered Organic Crystals on Graphene. J Am Chem Soc, vol. 135, No. 9, 2013, p. 3680-3687.
9.S. S. Roy, D. J. Bindl, and M. S. Arnold, Templating Highly Crystalline Organic Semiconductors Using Atomic Membranes of Graphene at the Anode/Organic Interface. The Journal of Physical Chemistry Letters, vol. 3, No. 7, 2012, p. 873-878.
10.D. Hong, Y. R. Do, H. T. Kwak, et al., Structural Templating and Growth Behavior of Copper Phthalocyanine Thin Films Deposited on A Polycrystalline Perylenetetracarboxylic Dianhydride Layer. Journal of Applied Physics, vol. 109, No. 6, 2011, p. 0635071-06350714.
11.P. Sullivan, T. S. Jones, A. J. Ferguson, et al., Structural Templating as A Route to Improved Photovoltaic Performance in Copper Phthalocyanine/fullerene (C[sub 60]) Heterojunctions. Applied Physics Letters, vol. 91, No. 23, 2007, p. 233114.
12.C. H. Cheng, J. Wang, G. T. Du, et al., Organic Solar Cells with Remarkable Enhanced Efficiency by Using A CuI Buffer to Control The Molecular Orientation and Modify The Anode. Applied Physics Letters, vol. 97, No. 8, 2010, p. 0833051-0833053.
13.Y. Y. Lin, D. J. Gundlach, S. F. Nelson, et al., Stacked Pentacene Layer Organic Thin-film Transistors with Improved Characteristics. Electron Device Letters, IEEE, vol. 18, No. 12, 1997, p. 606-608.
14.L. Zhou, A. Wanga, S. C. Wu, et al., All-organic Active Matrix Flexible Display. Applied Physics Letters, vol. 88, No. 8, 2006, p. 083502.
15.T. W. Kelley, P. F. Baude, C. Gerlach, et al., Recent Progress in Organic Electronics:  Materials, Devices, and Processes. Chemistry of Materials, vol. 16, No. 23, 2004, p. 4413-4422.
16.S. Yoo, B. Domercq, and B. Kippelen, Efficient Thin-film Organic Solar Cells Based on Pentacene/C[sub 60] Heterojunctions. Applied Physics Letters, vol. 85, No. 22, 2004, p. 5427-5429.
17.A. C. Mayer, M. T. Lloyd, D. J. Herman, et al., Postfabrication Annealing of Pentacene-based Photovoltaic Cells. Applied Physics Letters, vol. 85, No. 25, 2004, p. 6272-6274.
18.J. Gotzen, D. Kafer, C. Woll, et al., Growth and Structure of Pentacene Films on Graphite: Weak Adhesion as A Key for Epitaxial Film Growth. Physical Review B, vol. 81, No. 8, 2010, p. 085440.
19.W. H. Lee, J. Park, S. H. Sim, et al., Surface-directed Molecular Assembly of Pentacene on Monolayer Graphene for high-performance organic transistors. J Am Chem Soc, vol. 133, No. 12, 2011, p. 4447-4454.
20.K. Leo, The World of Organic Semiconductors
21.Fulleren and pentacene molecular structure. Available from: http://en.wikipedia.org/wiki/Pentacenehttps://en.wikipedia.org/wiki/Fullerene.
22.Benzene orbital. Available from: http://www.thestudentroom.co.uk/showthread.php?t=1493914.
23.K. Ihm, B. Kim, T. H. Kang, et al., Molecular Orientation Dependence of Hole-injection Barrier in pentacene thin film on the Au surface in organic thin film transistor. Applied Physics Letters, vol. 89, No. 3, 2006, p. 033504.
24.G. Horowitz, B. Bachet, A. Yassar, et al., Growth and Characterization of Sexithiophene Single Crystals. Chemistry of Materials, vol. 7, No. 7, 1995, p. 1337-1341.
25.K. N. Baker, A. V. Fratini, T. Resch, et al., Crystal Structures, Phase Transitions and Energy Calculations of Poly(p-phenylene) Oligomers. Polymer, vol. 34, No. 8, 1993, p. 1571-1587.
26.S. Hotta and K. Waragai, Crystal Structures of Oligothiophenes and Their Relevance to Charge Transport. Advanced Materials, vol. 5, No. 12, 1993, p. 896-908.
27.H. Moon, R. Zeis, E. J. Borkent, et al., Synthesis, Crystal Structure, and Transistor Performance of Tetracene Derivatives. Journal of the American Chemical Society, vol. 126, No. 47, 2004, p. 15322-15323.
28.J. E. Anthony, D. L. Eaton, and S. R. Parkin, A Road Map to Stable, Soluble, Easily Crystallized Pentacene Derivatives. Organic Letters, vol. 4, No. 1, 2001, p. 15-18.
29.D. E. Janzen, M. W. Burand, P. C. Ewbank, et al., Preparation and Characterization of π-Stacking Quinodimethane Oligothiophenes. Predicting Semiconductor Behavior and Bandwidths from Crystal Structures and Molecular Orbital Calculations. Journal of the American Chemical Society, vol. 126, No. 46, 2004, p. 15295-15308.
30.J. E. Anthony, J. S. Brooks, D. L. Eaton, et al., Functionalized Pentacene: Improved Electronic Properties from Control of Solid-State Order. Journal of the American Chemical Society, vol. 123, No. 38, 2001, p. 9482-9483.
31.C. D. Sheraw, T. N. Jackson, D. L. Eaton, et al., Functionalized Pentacene Active Layer Organic Thin-Film Transistors. Advanced Materials, vol. 15, No. 23, 2003, p. 2009-2011.
32.S. C. B. Mannsfeld, A. Virkar, C. Reese, et al., Precise Structure of Pentacene Monolayers on Amorphous Silicon Oxide and Relation to Charge Transport. Advanced Materials, vol. 21, No. 22, 2009, p. 2294-2298.
33.D. Mastromatteo, G. Macchi, P. Campiglio, et al., Novel organic paramagnetic nanofibers and nanostructures: A spectroscopic investigation. Chemical Physics Letters, vol. 498, No. 1–3, 2010, p. 129-133.
34.D. H. Kim, Y. Jang, Y. D. Park, et al., Surface-Induced Conformational Changes in Poly(3-hexylthiophene) Monolayer Films. Langmuir, vol. 21, No. 8, 2005, p. 3203-3206.
35.H. Sugimura. Organic monolayer and organic-inorganic multilayers fabricated by self-assembly. Available from: http://www.mtl.kyoto-u.ac.jp/english/laboratory/nanoscopic/nanoscopic.htm#1.
36.W. Chen, D. Chen Q, Y. L. Huang, et al., Molecular Orientation Dependent Energy Level Alignment at Organic-Organic Heterojunction Interfaces. The Journal of Physical Chemistry C, vol. 113, No. 29, 2009, p. 12832-12839.
37.I. Salzmann, A. Moser, M. Oehzelt, et al., Epitaxial Growth of π-Stacked Perfluoropentacene on Graphene-Coated Quartz. ACS Nano, vol. 6, No. 12, 2012, p. 10874-10883.
38.A. K. Geim and K. S. Novoselov, The Rise of Graphene. Nature Materials, vol. 6, No. 3, 2007, p183-191.
39.T. Szabo, O. Berkesi, P. Forgo, et al., Evolution of Surface Functional Groups in a Series of Progressively Oxidized Graphite Oxides. Chemistry of Materials, vol. 18, No. 11, 2006, p. 2740-2749.
40.V. Coropceanu, J. Cornil, Demetrio A. da Silva Filho, et al., Charge Transport in Organic Semiconductors. Chemical Reviews, vol. 107, No. 4, 2007, p. 926-952.
41.S. Stankovich, R. D. Piner, X. Chen, et al., Stable Aqueous Dispersions of Graphitic Nanoplatelets via The Reduction of Exfoliated Graphite Oxide in The Presence of Poly(sodium 4-styrenesulfonate). Journal of Materials Chemistry, vol. 16, No. 2, 2006, p. 155-158.
42.R. R. Nair, P. Blake, A. N. Grigorenko, et al., Fine Structure Constant Defines Visual Transparency of Graphene. Science, vol. 320, No. 5881, 2008, p. 1308.
43.S. Suzuki and M. Miyayama, Lithium Intercalation Properties of Octatitanate Synthesized through Exfoliation/Reassembly. The Journal of Physical Chemistry B, vol. 110, No. 10, 2006, p. 4731-4734.
44.Wang, K. Takada, A. Kajiyama, et al., Synthesis of a Li−Mn-oxide with Disordered Layer Stacking through Flocculation of Exfoliated MnO2 Nanosheets, and Its Electrochemical Properties. Chemistry of Materials, vol. 15, No. 23, 2003, p. 4508-4514.
45.N. Miyamoto, Y. Yamada, S. Koizumi, et al., Extremely Stable Photoinduced Charge Separation in a Colloidal System Composed of Semiconducting Niobate and Clay Nanosheets. Angewandte Chemie International Edition, vol. 46, No. 22, 2007, p. 4123-4127.
46.T. Yui, Y. Kobayashi, Y. Yamada, et al., Photochemical Electron Transfer Though The Interface of Hybrid Films of Titania Nano-sheets and Mono-dispersed Spherical Mesoporous Silica Particles. Physical Chemistry Chemical Physics, vol. 8, No. 39, 2006, p. 4585-4590.
47.H. Sato, K. Okamoto, K. Tamura, et al., A Heterojunction Photodiode Operating at Inorganic Nanosheet Interfaces. Applied Physics Express, vol. 1, 2008, p. 035001-1- p035001-3.
48.M. Osada, Y. Ebina, K. Takada, et al., Gigantic Magneto–Optical Effects in Multilayer Assemblies of Two-Dimensional Titania Nanosheets. Advanced Materials, vol. 18, No. 3, 2006, p. 295-299.
49.T. Kietzke, Recent Advances in Organic Solar Cells. Advances in OptoElectronics, vol. 2007, 2007, p. 1-15.
50.B. Kippelen and J. L. Bredas, Organic photovoltaics. Energy & Environmental Science, vol. 2, No. 3, 2009, p. 241-332.
51.J. Stohr, Nexafs Spectroscopy. 1996: Springer-Verlag. p. 403.
52.The free encyclopedia From Wikipedia. Atomic force microscopy. Available from: http://en.wikipedia.org/wiki/File:Atomic_force_microscope_block_diagram.svg.
53.D. J. Gardiner, Practical Raman Spectroscopy, ed. P.R. Graves. 1989.
54.H. L. Cheng, Y. S. Mai, W. Y. Chou, et al., Thickness-Dependent Structural Evolutions and Growth Models in Relation to Carrier Transport Properties in Polycrystalline Pentacene Thin Films. Advanced Functional Materials, vol. 6, No. 9, 2008, p. 3639-3649.
55.D. Kafer and G. Witte, Evolution of pentacene films on Ag(111): Growth beyond the first monolayer. Chemical Physics Letters, vol. 442, No. 4-6, 2007, p. 376-383.
56.D. M. DeLongchamp, E. K. Lin, and D. A. Fischer, Organic semiconductor Structure and Chemistry from Near-edge X-ray Absorption Fine Structure (NEXAFS) Spectroscopy. 2005, p. 59400A-1- p. 59400A-11.
57.H. L. Cheng, X. W. Liang, W. Y. Chou, et al., Raman Spectroscopy Applied to Reveal Polycrystalline Grain Structures and Carrier Transport Properties of Organic Semiconductor Films: Application to Pentacene-based Organic Transistors. Organic Electronics, vol. 10, No. 2, 2009, p. 289-298.
58.Y. Yi, V. Coropceanu, and J. L. Bredas, Exciton-Dissociation and Charge-Recombination Processes in Pentacene/C60 Solar Cells: Theoretical Insight into The Impact of Interface Geometry. Journal of the American Chemical Society, vol. 131, No. 43, 2009, p. 15777-15783.