Improved efficacy and operation-lifetime of all-solution-process small molecule OLEDs by blade coating
| Autor: | Chang, Yu-Fan, 張宇帆 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 In this thesis, I focus on the device engineering and the improvement of operation-lifetime of all-solution-processed organic light-emitting diodes (OLEDs) through adopting a blade coating process. In the first part of the thesis, I reviewed the background of OLEDs, the literature review on OLEDs development, the solution-process OLEDs, and the means of improving OLEDs. In the second part, I systematically investigate the properties of all-solution-processed OLEDs, such as the material solubility, thin-film morphology, and device performance. From chapter 2 to chapter 5, blade coating with substrate heating and hot wind was demonstrated to be a general approach to the multi-layer deposition of unmodified small-molecule organic semiconductors. The optimized OLEDs structure developed for vacuum deposition can therefore be exactly copied through a low cost blade coating method involving a solution process. A general method for characterizing the interface dissolution in multi-layer OLEDs by blade coating was developed on the basis of fluorescence microscopy. Tris (8-hydroxyquinolinato) aluminum (Alq3) is a relatively stable electron-transporting material commonly used in evaporation. However, depositing Alq3 through a solution process is difficult because of its extremely low solubility in organic solvents, which is due to its symmetrical molecular structure. In this study, Alq3 was successfully deposited through blade coating at an extremely low concentration below 0.1wt. %, and applied to the fluorescent materials used in OLEDs. The third part of this thesis, described an effective method for fabricating all-solution-processed phosphorescent OLEDs and fluorescent OLEDs with a long operation-lifetime. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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