Extraction Efficiency Enhancement of Flexible Green PLED with Nanoimprinted Patterned Substrate

• Main Authors: Chung-Chun Liu, 劉重均
• Other Authors: Pei-Kuen Wei
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/51433886977212477397

碩士 === 國立臺灣海洋大學 === 光電科學研究所 === 98 === Due to the index mismatch of the layered PLED structure, the extraction efficiency is limited to about 25%. Most light is confined in the transparent substrate and the organic layers. It is about 40% of light is tapped in the substrate. Therefore how to extract the confined light is an important issue for improving the PLED efficiency. In this thesis, we used nanoimprint technology to fabricate nanostructures onto our device substrates to extract the light of substrate mode. We used the anodic aluminum oxide (AAO) substrate as our imprint mold and patterned nanopillars structures with different height and diameter on the front side of the testing PLED devices. In order to optimize the extraction efficiency by these nanopillars, we systematically tested different temperatures, pressures and pressing time in order to fabricate the appropriate nanostructures. In the case of 170℃ temperature and 25 kgw/cm2 pressure for 10 minutes, we obtained the best nanostructure. The nanostructure is acted as a anti-reflection layer. It lowered down the reflectivity from 10.2% to 6.6%. Due to the destroy of total internal reflection of the guiding mode in the substrate, we obtain 68.9% enhancement compared with the conventional devices with flat substrates.