Blue light-emitting diodes with good spectral stability based on blends of poly(9,9-dioctylfluorene): Interplay between morphology, photophysics, and device performance

被引:202
作者
Kulkarni, AP
Jenekhe, SA [1 ]
机构
[1] Univ Washington, Dept Chem Engn, Seattle, WA 98195 USA
[2] Univ Washington, Dept Chem, Seattle, WA 98195 USA
关键词
D O I
10.1021/ma0344700
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
Spectrally stable blue electroluminescence (EL) is obtained from single-layer polymer light-emitting diodes fabricated from binary blends of conjugated poly(9,9-dioctylfluorene) (PFO) with either thermally stable poly(vinyl diphenylquinoline) (PVQ) or polystyrene. The brightness and EL efficiency of the polymer blend LEDs were enhanced by a factor of 5-14 compared to the PFO homopolymer devices. The additional green emission observed in the EL spectra of pure PFO devices was substantially suppressed in the blend LEDs. The electrical characteristics of the diodes and electric-field-modulated PL spectroscopy results indicate increased spatial confinement induced exciton stability and electron-hole recombination efficiency in the blend devices. The variation of the device performance with blend composition is related to the phase-separated morphology of the blends. The origin of the spectral stability lies in the improved thermal stability of the PFO:PVQ blends due to the high glass transition temperature (T-g) of PVQ (185 degreesC). These results demonstrate that blending of PFO with high Tg charge transport or charge blocking polymers is a simple strategy to overcoming the problem of poor spectral stability of blue-emitting polyfluorenes.
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收藏
页码:5285 / 5296
页数:12
相关论文
共 68 条
  • [1] Electrochemical properties and electronic structures of conjugated polyquinolines and polyanthrazolines
    Agrawal, AK
    Jenekhe, SA
    [J]. CHEMISTRY OF MATERIALS, 1996, 8 (02) : 579 - 589
  • [2] SYNTHESIS AND PROCESSING OF HETEROCYCLIC POLYMERS AS ELECTRONIC, OPTOELECTRONIC, AND NONLINEAR OPTICAL-MATERIALS .2. NEW SERIES OF CONJUGATED RIGID-ROD POLYQUINOLINES AND POLYANTHRAZOLINES
    AGRAWAL, AK
    JENEKHE, SA
    [J]. MACROMOLECULES, 1993, 26 (05) : 895 - 905
  • [3] Polybenzobisazoles are efficient electron transport materials for improving the performance and stability of polymer light-emitting diodes
    Alam, MM
    Jenekhe, SA
    [J]. CHEMISTRY OF MATERIALS, 2002, 14 (11) : 4775 - 4780
  • [4] Photovoltaic performance and morphology of polyfluorene blends: A combined microscopic and photovoltaic investigation
    Arias, AC
    MacKenzie, JD
    Stevenson, R
    Halls, JJM
    Inbasekaran, M
    Woo, EP
    Richards, D
    Friend, RH
    [J]. MACROMOLECULES, 2001, 34 (17) : 6005 - 6013
  • [5] Field-effect mobility of charge carriers in blends of regioregular poly(3-alkylthiophene)s
    Babel, A
    Jenekhe, SA
    [J]. JOURNAL OF PHYSICAL CHEMISTRY B, 2003, 107 (08) : 1749 - 1754
  • [6] Babel A, 2002, J PHYS CHEM B, V106, P6129, DOI 10.1021/jp0206951
  • [7] Optimisation of polyfluorenes for light emitting applications
    Becker, S
    Ego, C
    Grimsdale, AC
    List, EJW
    Marsitzky, D
    Pogantsch, A
    Setayesh, S
    Leising, G
    Müllen, K
    [J]. SYNTHETIC METALS, 2001, 125 (01) : 73 - 80
  • [8] Bernius MT, 2000, ADV MATER, V12, P1737, DOI 10.1002/1521-4095(200012)12:23<1737::AID-ADMA1737>3.0.CO
  • [9] 2-N
  • [10] Electrical and photoinduced degradation of polyfluorene based films and light-emitting devices
    Bliznyuk, VN
    Carter, SA
    Scott, JC
    Klärner, G
    Miller, RD
    Miller, DC
    [J]. MACROMOLECULES, 1999, 32 (02) : 361 - 369