Synthesis and Characterization of Organic Light-Emitting Copolymers Containing Naphthalene

• Published in: Macromolecular research 2009, 17(2), , pp.91-98
• Main Authors: Kim, Jung-Sik, Heo, Jun, Kang, Pengtao, Kim, Jin Hak, Jung, Sung Ouk, Kwon, Soon-Ki, Kim, Un-Kyung, Kim, Yun-Hi
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Nanochemistry; Nanotechnology; Physical Chemistry; Polymer Sciences; Soft and Granular Matter; 고분자공학
• ISSN: 1598-5032; 2092-7673
• DOI: 10.1007/bf03218660

Conjugated PPV-derived block copolymers containing 2-ethylhexyloxynaphthalene unit were synthesized and characterized in this study. The resulting polymers were soluble in common organic solvents and showed good thermal stabilities. The weight-average molecular weights ( M w ) of the copolymers ranged from 246,000 to 475,000 with PDIs of 1.3∼2.1. The optical properties of these polymers, measured both in a chloroform solution and on a film, showed a maximum absorption at 405∼476 nm for Copolymers I∼VIII. In the PL spectra, Copolymers I∼VIII showed maximum peaks at 510∼566 nm. The HOMOs, LUMOs and band gaps of the PPV derivatives of Copolymers I∼VIII were 5.30∼5.77, 3.04∼3.24, and 2.5∼2.2 eV, respectively. The multi-layered, light-emitting diodes of ITO/PEDOT/copolymers/LiF/Al exhibited turn-on voltages of 6∼2.5 V. Copolymer VIII exhibited the maximum brightness of 3,657 cd/m 2 . Particularly, Copolymer VII, with an identical composition of MEH-PPV and naphthalene-PPV, showed a maximum luminance efficiency and power efficiency of 2.63 cd/A and 1.06 lm/W, respectively.