Fluorescent and phosphorescent polymeric white-light emitting diodes based on polyfluorene copolymers

• Main Authors: Po-I Lee, 李柏毅
• Other Authors: Steve Lien-Chung Hsu
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/92398454462695003464

博士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 95 === The dissertation is divided into three parts. Part 1: Novel electrophosphorescent polymers were prepared from quinoline and pyridine end-capped polyfluorenes reacted with 4,4'-dimethyl-2,2'-bipyridyl (tricarbonyl)rhenium(I) chloride. Fourier transform infrared (FT-IR) and photoluminescence (PL) spectroscopy confirmed that the rhenium complex was successfully incorporated into the polymer backbones. The energy transfer can be reached by balanced triplet energy state. The emission contributions of polyfluorene and the organic complex were found from the electroluminescence (EL) spectra. Part 2: New polymer white-light-emitting diodes from single polymer systems have been developed. The polymer systems were based on poly(fluorene-co-benzothiadiazole) backbones end-capped with a dye(N-phenyl- 1,8-naphthalimide). By changing the molar ratio of these three units, the electroluminescence (EL) spectra can be adjusted to white-light emission with a structure of indium tin oxide/ poly(3,4-ethylenedioxythiophene): poly(styrene sulfonic acid)/emission layer/Ca/Ag. The highest brightness in such a device configuration is 251 cd/m2 at a current density of 400 A/m2 with Commission Internationale de l’Eclairage (CIE) coordinates of (0.31, 0.39). The EL spectra show color stability over different operating voltages. Part 3: New white polymeric light-emitting diodes (WPLEDs) from phosphorescent single polymer systems have been developed using dicotylfluorene monomer copolymerized with a phosphorescent dye, and end-capped with dye. All of the copolymers have good thermal stability with 5 % weight loss temperatures at 380~413°C and glass transition temperatures at 75~137°C. We obtained white-light-emission devices by adjusting the molar ratio of the co-monomers with a structure of indium tin oxide/poly(3,4-ethylenedioxythiophene): poly(styrene sulfonic acid)/ polyvinylcarbazole (PVK)/emission layer/Ca/Ag. The highest brightness in such a device configuration is 300 cd/m2 at a current density of 2900 A/m2 with Commission Internationale de l’Eclairage (CIE) coordinates of (0.33, 0.34).