Polymer(Korea) (폴리머)

The Polymer Society of Korea (한국고분자학회)
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Synthesis and Characterization of Electroluminescent Conjugated Polymers Containing Sulfone Group in the Main Chain

주사슬에 설폰기를 함유하는 전기발광 공액 고분자의 합성과 특성분석

  • Kang Min Sung (School of Materials Science and Engineering, Seoul National University) ;
  • Jung Ho Kuk (School of Materials Science and Engineering, Seoul National University) ;
  • Park Soo Young (School of Materials Science and Engineering, Seoul National University) ;
  • Kim Jang-Joo (School of Materials Science and Engineering, Seoul National University)
  • Published : 2005.07.01
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Abstract

As a new class of electroluminescent (EL) polymers, PPV-based polymers containing sulfone group in the main chain were synthesized through Witting polymerization reaction to control n-conjugation length and energy levels for predictable light emission and enhanced device performance. These EL polymers showed good solubility in common organic solvents and high thermal stability with initial decomposition temperature of ca. $400^{circ}$ and glass transition temperature around $200^{circ}C$ Emission colors were tuned from green to deep blue by reducing ${\pi}$-conjugated length between sulfone groups. It was also noted from the cyclic voltammetry (CV) measurements and semiempirical calculations that sulfone group with high electron affinity effectively lowered HOMO-LUMO energy levels to enhance EL device performance.

중합체의 공액길이를 제어하고 이들이 갖는 에너지 준위를 조절하며, 발광성능향상과 발광파장을 조절하려는 목적으로 설폰기가 포함된 페닐렌-비닐렌계의 새로운 전기발광 고분자들을 Witting 중합을 통해 합성하였다. 합성된 고분자들은 일반 유기 용매에 좋은 용해성을 보였고 $400^{circ}C$ 정도의 초기분해온도와 $200^{circ}C$ 전후의 높은 유리전이온도를 가짐으로써 열적 안정성이 매우 높음을 확인하였다. 각각의 고분자는 용액과 필름상태에서 모두 설폰기의 꺾임에 의해 공액길이가 짧아질수록 UV 흡수와 발광 스펙트럼이 단파장으로 이동하였고 이를 통해 설폰기가 효율적으로 발광파장을 제어하는 것을 확인하였다. 또한 CV측정과 이론적인 계산을 통해 전자친화도가 큰 설폰기에 의해서 합성된 고분자들의 HOMO 및 LUMO 에너지 준위가 상대적으로 낮아짐으로써 소자의 전기발광특성이 향상됨을 확인하였다.

Keywords

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