Article
  • Polarized Light Emission of Liquid Crystalline Polymer Blends
  • Kim YC, Cho HN, Kim DY, Hong JM, Song NW, Kim D, Kim CY
  • 액정성 고분자 블렌드의 편발광
  • 김영철, 조현남, 김동영, 홍재민, 송남응, 김동호, 김정엽
Abstract
Fluorene-based light emitting polymer blends with liquid crystalline characteristics were studied on effective energy transfer and dichroic characteristics. Incorporating 0.5wt% of the non-liquid crystalline into the liquid crystalline polymer suppressed the PL emission at 420nm on photoexicitation at 360nm, but generated a new PL emission of the non-liquid crystalline polymer at 480nm. The highest PL intensity at 480nm, which was 13 times stronger than those of the two polymers before blending, was observed for a blend with 2.0wt% of the non-liquid crystalline polymer. When the molecules of the blends were aligned on a rubbed polyimide surface by a heating-cooling process, the dichroic ratio and the order parameter were 2.0 and 0.25 respectively. Time-correlated single photon counting(TCSPC) study revealed that the time required for energy transfer between the two chromophores was shortened by 93 ps when the blends were aligned on the rubbed polyimide surface by the heating-cooling process. The thermal treatment also enhanced the energy transfer efficiency by 9%.

액정성을 가지는 플로렌계 발광고분자에 비액정성 플로렌계 발광고분자를 첨가한 블렌드를 제조하여 에너지전달 효과와 흡광 및 발광 이방성에 대하여 고찰하였다. 비액정성 고분자를 액정성고분자에 0.5wt% 첨가하고 360nm로 여기한 결과, 420nm에서 관찰되었던 액정성 고분자의 발광피크는 거의 사라졌으며 대신 비액정성 고분자에 의한 480nm에서의 새로운 발광피크가 관찰되었다. 블렌드 시료의 480nm 발광은 비액정성 고분자가 2.0wt% 첨가되었을 때 가장 강했으며, 발광강도는 블렌딩 이전의 각 고분자보다 13배 증가하였다. 블렌드내의 분자들을 마찰 폴리이미드기판상에서 가열-냉각시켜 배향시키면 시료의 발광 이방성과 order parameter 는 각각 2.0 및 0.25를 나타내었다. 시간 상관 단광자 계수법(TCSPC)에 의해 고찰한 결과, 마찰 폴리이미드 기판상에서의 배향에 의해 두 발광고분자간의 에너지전달에 필요한 시간은 93 ps만큼 단축되며 에너지전달 효율은 9% 증가함을 알 수 있었다.

Keywords: photoluminescence; polarized light emission; liquid crystalline polymer blend; energy transfer; time-correlated single photon counting(TCSPC)

References
  • 1. Burroughes JH, Bradley DDC, Brown AR, Marks RN, Mackay K, Friend RH, Burn PL, Holmes AB, Nature, 347, 539 (1990)
  •  
  • 2. Cho HN, Kim JK, Kim DY, Kim CY, Song NW, Kim D, Macromolecules, 32(5), 1476 (1999)
  •  
  • 3. Hide F, Diazgarcia MA, Schwartz BJ, Andersson MR, Pei QB, Heeger AJ, Science, 273(5283), 1833 (1996)
  •  
  • 4. Heeger AJ, Kivelson S, Schrieffer JR, Su WP, Rev. Mod. Phys., 60, 781 (1998)
  •  
  • 5. Tomozawa H, Braun D, Phillips S, Heeger AJ, Kroemer H, Synth. Met., 22, 63 (1987)
  •  
  • 6. Yu G, Heeger AJ, J. Appl. Phys., 78, 4510 (1995)
  •  
  • 7. Burroughes JH, Jones CA, Friend RH, Nature, 335, 137 (1998)
  •  
  • 8. Yang Y, Heeger AJ, Nature, 372(6504), 344 (1994)
  •  
  • 9. Pei QB, Yu G, Zhang C, Yang Y, Heeger AJ, Science, 269(5227), 1086 (1995)
  •  
  • 10. Chen SH, Katsis D, Schmid AW, Mastrangelo JC, Tsutsui T, Blanton TN, Nature, 397(6719), 506 (1999)
  •  
  • 11. Montali A, Bastiaansen G, Smith P, Weder C, Nature, 392(6673), 261 (1998)
  •  
  • 12. Hamaguchi M, Yoshino K, Jpn. J. Appl. Phys., 34, L712 (1995)
  •  
  • 13. Bolognesi A, Bajo G, Paloheimo J, Ostergard T, Stubb H, Adv. Mater., 9(2), 121 (1997)
  •  
  • 14. Yanagi H, Okamoto S, Appl. Phys. Lett., 71(18), 2563 (1997)
  •  
  • 15. Grell M, Bradly DDC, Inbasekaran M, Woo EP, Adv. Mater., 9(10), 798 (1997)
  •  
  • 16. Chen SH, Conger BM, Mastrangelo JC, Kende AS, Kim DU, Macromolecules, 31(23), 8051 (1998)
  •  
  • 17. Sariciftci NS, Lemmer U, Vacar D, Heeger AJ, Janssen RAJ, Synth. Met., 84, 609 (1997)
  •  
  • 18. Peeters E, Christiaans MPT, Janssen RAJ, Schoo HFM, Dekkers HPJM, Meijer EW, J. Am. Chem. Soc., 119(41), 9909 (1997)
  •  
  • 19. Kopp VI, Fan B, Vithana HKM, Genack AZ, Optics Lett., 23(21), 1707 (1998)
  •  
  • 20. Gilbert A, Baggot JEssentials of Molecular Chemistry, Section 5.3, Blackwell Scientific Publications, Cambridge, 1991 (1991)
  •  
  • 21. Shoustikov AA, You Y, Thomson ME, IEEE J. Selected Topics Quantum Electron., 4(1), 3 (1998)
  •  
  • 22. Lee MY, Kim D, J. Opt. Soc. Korea, 5(1), 90 (1994)
  •  
  • 23. Cho HN, Kim DY, Kim YC, Lee JY, Kim CY, Adv. Mater., 9(4), 326 (1997)
  •  
  • 24. Conger BM, Mastrangelo JC, Chen SH, Macromolecules, 30(14), 4049 (1997)
  •  
  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2023 Impact Factor : 0.4
  • Indexed in SCIE

This Article

  • 2000; 24(2): 211-219

    Published online Mar 25, 2000