Synthesis and Optical Properties of Poly(7,10- benzacenaphthene vinylene) Derivatives

• Main Authors: Lin, Jian-Hung, 林建弘
• Other Authors: Yang, Sheng-Hsiung
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/13264675842394801075

碩士 === 國立交通大學 === 影像與生醫光電研究所 === 100 === The aim of this research is to synthesize two kinds of poly(7,10- benzacenaphthene vinylene) derivatives with two different side substituents, including n-decyl group and biphenyl liquid crystalline mesogen. In order to increase molecular weights and tune emitting colors, copolymerization was also carried out with the monomer of MEH-PPV. In addition to the identification of chemical structures, the optical, electrochemical, and thermal properties of all polymers were investigated as well. Double-layer polymer light-emitting diodes were fabricated, and their potential use in electroluminescent devices were evaluated. All polymers were synthesized via the Gilch polymerization. Polymer 1P is an oligomer with a glass transition temperature of 157 oC. The molecular weight of polymer 2P is increased to 2.04×105 g/mol; its glass transition temperature is also increased to 207 oC, as a result of incorporating biphenyl liquid crystalline mesogen. The maximum absorption and PL emission wavelengths of 1P thin film are located at 370 and 510 nm, respectively. The maximum absorption and PL emission wavelengths of 2P thin film are located at 365 and 508 nm, respectively. Both of them show bluish-green fluorescence. The CV analysis shows that the HOMO, LUMO, and bandgap of polymers 1P and 2P are -5.99, -3.05, 2.94 eV, and -5.63, -3.05, 2.94 eV, respectively. The difference in HOMO is due to the liquid crystalline mesogen attached to 2P chains. The maximum absorption wavelength of 3P thin film is found at 368 nm, while its oxidation potential is 1.54 eV, which are similar to 1P. The optical properties of copolymers 4P and 6P are similar. Among these materials 5P shows better device performance. The brightness and current efficiency of 5P were reached 202 cd/m2 and 0.009 cd/A, respectively, from a device configuration of ITO/PEDOT/polymer/Al.