Title Page
Abstract
Contents
Chapter 1. Introduction 13
1.1. Organic Thin Film Transistor; OTFT 13
1.1.1. Device geometry 15
1.1.2. Work principle 17
1.1.3. Surface roughness 21
1.1.4. Leakage current 22
1.1.5. On / off ratio 23
1.2. Gate Dielectric Materials for OTFT 24
1.2.1. Background 24
1.2.2. Dielectric materials 25
1.2.3. Self photo-crosslinkerable polymer 26
1.2.4. Photo crosslinker 27
Chapter 2. Experiment 28
2.1. Instruments 28
2.2. Materials 29
2.3. Synthesis 30
2.3.1. Synthesis of a polyimide containing hydroxyl groups (DOCDA-6FHAB) 30
2.3.2. Synthesis of a polyimide containing double bonds with urethane linkage(DOCDA-6FHAB-IEM) 31
2.4. Patterning 32
2.4.1. Patterning process of photocurable polymer 32
2.4.2. Patterning process of photocurable polymer & photocrosslinker 33
Chapter 3. Result and Discussion 34
3.1. DOCDA-6FHAB 34
3.1.1. Structure identification 34
3.1.2. Thermal property 36
3.2. DOCDA-6FHAB-IEM 37
3.2.1. Structure identification 37
3.2.2. Thermal properties 43
3.2.3. Surface properties 45
3.3. Crosslinked DOCDA-6FHAB-IEM 46
3.3.1. Thin film fabrication of crosslinked DOCDA-6FHAB-IEM 46
3.3.2. Structure identification 47
3.3.3. Thermal properties 49
3.3.4. Surface properties 50
3.3.5. Electronic properties of device 52
3.4. Crosslinked DOCDA-6FHAB-IEM+TMTA 56
3.4.1. Thin film fabrication of crosslinked DOCDA-6FHAB-IEM+TMTA 56
3.4.2. Structure identification 57
3.4.3. Thermal properties 59
3.4.4. Surface properties 61
3.4.5. Electronic properties of device 64
Chapter 4. Conclusion 70
References 71
개요 74
Appendix 76
Table 1. Surface energy of DOCDA-6FHAB-IEM. 45
Table 2. Surface energy of DOCDA-6FHAB-IEM and crosslinked DOCDA-6FHAB-IEM. 50
Table 3. Summary of a crosslinked DOCDA-6FHAB-IEM film with the MIM capacitor structure. 53
Table 4. TFT characteristics of crosslinked DOCDA-6FHAB-IEM gate insulator. 55
Table 5. Surface energy of crosslinked DOCDA-6FHAB-IEM and crosslinked DOCDA-6FHAB-IEM+TMTA. 61
Table 6. Summary of a crosslinked DOCDA-6FHAB-IEM+TMTA film with the MIM capacitor structure. 65
Table 7. Summary of a crosslinked DOCDA-6FHAB-IEM and crosslinked DOCDA-6FHAB-IEM+TMTA film with the MIM capacitor structure. 66
Table 8. TFT characteristics of crosslinked DOCDA-6FHAB-IEM+TMTA gate insulator. 68
Table 9. TFT characteristics of crosslinked DOCDA-6FHAB-IEM and crosslinked DODCA-6FHAB-IEM+TMTA gate insulator. 69
Figure 1. The applications of OTFTs. 13
Figure 2. Advantages of Organic device. 14
Figure 3. Basic structure of OTFTs; (a) inverted-coplanar type (bottom gate/ bottom contact), (b) inverted-staggered type (bottom gate/top contact), (c) coplanar type (top... 15
Figure 4. Basic structure of organic thin film transistor (OTFT). 17
Figure 5. Schematic structure of working principle for OTFT. 18
Figure 6. Chemical structures of polmeric dielectric materials PVP (polyvinylphenol), poly(ethylene oxide), PVA (polyvinylalcohol), PMMA (polymethylmethacrylate), CYPEL... 25
Figure 7. Machanism of methacrylate esterification. 26
Figure 8. Chemical structure of main materials: (a) DOCDA-6FHAB-IEM (polymer), (b) TMTA (photo-crosslinker) (c) Irgacure 184 (photo-initiator). 27
Figure 9. Optical microscopy images of crosslinked DOCDA-6FHAB-IEM film (X100). 32
Figure 10. Optical microscopy images of crosslinked DOCDA-6FHAB-IEM+TMTA film (a) X50, (b) X100. 33
Figure 11. The ¹H NMR spectrum of DOCDA-6FHAB in DMSO. 34
Figure 12. The FT-IR spectrum of DOCDA-6FHAB in KBr pellet. 35
Figure 13. TGA of DOCDA-6FHAB. 36
Figure 14. The ¹H NMR spectrum of DOCDA-6FHAB-IEM in DMSO. 37
Figure 15. Proof of the ¹H NMR spectrum of DOCDA-6FHAB-IEM synthesis. 38
Figure 16. The FT-IR spectrum of IEM. 39
Figure 17. The FT-IR spectrum of DOCDA-6FHAB-IEM in KBr pellet. 40
Figure 18. Proof of the FT-IR spectrum of DOCDA-6FHAB-IEM synthesis. 41
Figure 19. TGA of DOCDA-6FHAB and DOCDA-6FHAB-IEM. 43
Figure 20. Optical microscopy images of water and diiodomethane drops on the surface of DOCDA-6FHAB-IEM film. 45
Figure 21. The FT-IR spectrum of crosslinked DOCDA-6FHAB-IEM in KBr pellet. 47
Figure 22. Proof of crosslinking of DOCDA-6FHAB-IEM. 48
Figure 23. TGA of DOCDA-6FHAB-IEM and crosslikned DOCDA-6FHAB-IEM. 49
Figure 24. Optical microscopy images of water and diiodomethane drops on the surface of (a) DOCDA-6FHAB-IEM film, (b) crosslinked DOCDA-6FHAB-IEM film. 50
Figure 25. AFM images (5 ㎛ x 5 ㎛) of crosslikned DOCDA-6FHAB-IEM. 51
Figure 26. (a) Capacitance vs. frequency and (b) leakage current density vs. electric field characteristics of crosslinked DOCDA-6FHAB-IEM layer. 52
Figure 27. (a) Transfer and (b) output characteristics of pentacene TFT with crosslinked DOCDA-6FHAB-IEM layer. 54
Figure 28. The FT-IR spectrum of TMTA crosslinker. 57
Figure 29. Proof of crosslinking of DOCDA-6FHAB-IEM+TMTA. 58
Figure 30. TGA of crosslinked DOCDA-6FHAB-IEM and crosslinked DOCDA-6FHAB-IEM+TMTA. 59
Figure 31. Optical microscopy images of water and diiodomethane drops on the surface of (a) DOCDA-6FHAB-IEM+TMTA film, (b) crosslinked DOCDA-6FHAB-IEM+TMTA film. 61
Figure 32. AFM images (5 ㎛ x 5 ㎛) of crosslinked DOCDA-6FHAB-IEM+TMTA. 63
Figure 33. (a) Capacitance vs. frequency and (b) leakage current density vs. electric field characteristics of a crosslinked DOCDA-6FHAB-IEM+TMTA layer. 64
Figure 34. (a) Transfer and (b) output characteristics of pentacene TFT with crosslinked DOCDA-6FHAB-IEM+TMTA layer. 67
Scheme 1. Chemical structures and synthetic routes of DOCDA-6FHAB. 30
Scheme 2. Chemical structures and Synthetic routes of DOCDA-6FHAB-IEM. 31
Scheme 3. Crosslinking machanism of DOCDA-6FHAB-IEM. 46
Scheme 4. Crosslinking machanism of DOCDA-6FHAB-IEM+TMTA. 56