Synthesis, Characterization and Hole-Buffering Application of Polyfluorene with Pendant Hydroxyethoxyethylimino Groups

• Main Authors: Yu-LinJheng, 鄭郁霖
• Other Authors: Yun Chen
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/w5358d

碩士 === 國立成功大學 === 化學工程學系 === 107 === Polymer light-emitting diodes (PLEDs) have attracted considerable attention for its self-emissive ability, flexibility and high efficiency. Charge balance is an essential factor to enhance device efficiency. Hole mobility is always higher than electron mobility in most conjugated organic materials. Therefore, materials with low-lying HOMO level to reduce hole mobility are effective in enhancing efficiency of PLEDs. In this study, we successfully synthesized a new polyfluorene (PFI) by the Suzuki-coupling reaction; the PFI is composed of polyfluorene core with pendant hydroxyethoxyethylimino groups. The PFI was spin coated on top of PEDOT:PSS as hole-buffering layer (HBL). The HOMO and LUMO levels of PFI were -5.63 eV and -2.41 eV, respectively, as estimated from the onset oxidation and onset reduction potentials obtained in cyclic voltammetric measurements. Multilayer PLED devices were successfully fabricated [ITO/PEDOT:PSS/PFI(HBL)/SY-PPV/LiF/Al] using PFI as HBL. Their maximum luminance and maximum current efficiency were 11,831 cd/m2 and 5.08 cd/A, respectively, superior to those of the device without HBL (6,138 cd/m2, 1.36 cd/A). Current results indicate that the PFI is a potential hole-buffering materials applicable in optoelectronic devices.