Synthesis and Characterization of Fluorinated Polyimides / Oxide Composite Films: Dielectric Properties and Applications as the Flexible Substrates for Organic Light Emitting Diodes
| Autor: | Sheng-Ting Huang, 黃升廷 |
|---|---|
| Rok vydání: | 2014 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 102 A novel diamine, 2,2’-bis[3,5-bis(trifluoromethyl)phenyl]-4,4’-oxydianiline (5) was synthesized by oxidation, bromination, Suzuki coupling reaction, and reduction from 4,4’-ODA. A novel polyimide(PI-12F) was prepared based on this novel diamine and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride(6FDA) by one-step method. The novel polyimide exhibited low dielectric constant and high optical transparency. PI-12F could dissolve in common organic solvents, even acetone at room temperature. The glass transition temperature (Tg) was 245℃.The 5% weight-loss temperature was 505℃.The UV-vis cut-off wavelength was 361 nm. The UV-vis λ80% was 410nm. The dielectric constant was 2.6. In order to enhance the properties of the PI-12F, PI-12F was further blended with silica, hollow silica sphere and titania to prepare the hybrid films (PI-12F/S, PI-12F/HS, PI-12F/T series). The glass transition temperature (Tg) of these three series of hybrid films were in the range of 241~250℃. The 5% weight-loss temperature were in the range of 446~504℃. We could presume the dielectric constant of hollow silica sphere was in the range of 2.7~3.3. If the dielectric constant of the polymer matrix was below 2.7, then the hollow silica sphere would increase the dielectric constant of the polymer. If the dielectric constant of the polymer matrix was above 3.3, then the hollow silica sphere would decrease the dielectric constant of the polymer. The UV-vis cut-off wavelength of PI-12F/S and PI-12F/T series were in the range of 377~406 nm. The UV-vis λ80% were in the range of 432~484nm. The refractive index were in the range of 1.52~1.61. Flexible OLEDs were fabricated with PI-12F, PI-12F/S and PI-12F/T series as substrates. The efficiency of OLED with PI-12F/40T as substrate was 12.6 Cd/A. Compared with the OLED with glass substrate, the efficiency of OLED with PI-12F/40T increased 28%. Therefore, PI-12F/40T would be a potential flexible substrate for flexible OLED. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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