Abstract
This research focuses on the morphologies of polymers after the heat treatment, as the different temperature and time. To make a polymeric light emitting device (PLED), the wet procedure is used to composite the organic layer, such as spin coating, and has the very tremendous influence to its efficiency and performance. Thermal annealing plays an important role on it, especially the relationship between the glass transition temperature (Tg) and the boiling temperature of the solvent.
In the experiment of wet procedure, we dissolved the green light polymer (PFG) into the chlorobenzene, and the Tg of PFG is about 108¢XC, and the solvent has been boiled at 134¢XC. After spin coating in the glove box, the organic layer became the liquid thin film, and we must bake it to the solid state. It took different morphologies of the polymers by changing the thermal temperature and time. And we can suppose the molecular arrangement from the ultraviolet-visible absorption spectrometry (UV-vis) and photoluminescence spectrometry (PL). Otherwise, we analyzed the surface morphology by using atomic force microscopy (AFM). Though the measurement of X-ray diffraction made the crystallinity of polymers discovered. After all, we prepared ITO(140nm) / PEDOT:PSS(65nm) /PFG(60nm)/ LiF(1nm) / Ca(10nm) / Al(200nm) for the PLED structure.
According to the characteristic of the device, we can discuss what happen to the light emitting layer after thermal annealed. In the conclusion, we got the best performance when thermal temperature is nearby or above the Tg with the longer baking time. Respectively, the green light had the maximum luminance at 10.5v of 38710 cd/m2, and the current efficiency was 7.62 cd/A, and power efficiency was 2.66 lm/watt. And we have found higher baking temperature than Tg, as more than 135oC, made the worse performance through the longer time; except the 125oC. A transition thermal temperature, a little higher than Tg, made the performance keep stable after baking for a long time.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0818109-170138 |
| Date | 18 August 2009 |
| Creators | Ou, Chun-Hsien |
| Contributors | Chih-Chien Lee, Ping-Tsung Huang, Yu-Kai Han, Mei-Ying Chang, Jui-Ming Yeh |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0818109-170138 |
| Rights | campus_withheld, Copyright information available at source archive |
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