Efficient electron injection in blue-emitting polymer light-emitting diodes with LiF/Ca/Al cathodes

Brown, T. M.; Friend, R. H.; Millard, I. S.; Lacey, D. J.; Burroughes, J. H.; Cacialli, F.
July 2001
Applied Physics Letters;7/9/2001, Vol. 79 Issue 2
Academic Journal
We report electroabsorption and electroluminescence investigations of polymer light-emitting diodes featuring a LiF/Ca/Al cathode, for efficient electron injection into the electroluminescent polymer layer. Our measurement of the built-in potential gives direct evidence of a sizeable reduction of the cathodic barrier height not only with respect to Ca, but also versus LiF/Al or CsF/Al bilayer cathodes, currently amongst the most efficient electron injectors for low electron affinity polymers. In blue-emitting (∼2.7 at peak) polyfluorene-based LEDs, with poly(ethylenedioxythiophene)/poly(styrene sulphonic acid) anodes and LiF/Ca/Al cathodes, we measure a built-in potential of 2.7 V, a luminance of ∼1600 cd/m2 (the highest among the devices studied here) at a driving voltage of 5 V, and efficiencies as high as ∼3 lm/W. We also find that the turn-on voltage essentially coincides with the built-in potential within the experimental error. © 2001 American Institute of Physics.


Related Articles

  • Electroluminescence of polymer/J-aggregate composites. Mal'tsev, Eugene I.; Lypenko, Dmitry A.; Shapiro, Boris I.; Milburn, George H.W.; Wright, Jeffrey; Hendriksen, Andre; Berendyaev, Vladimir I.; Kotov, Boris V.; Vannikov, Anatoly V. // Applied Physics Letters;9/27/1999, Vol. 75 Issue 13, p1896 

    Studies the efficient electroluminescence in single-layer light-emitting diodes based on electron hole conducting polymers containing the nanocrystalline phase of cyanine dyes (J-aggregates). Narrow emission band with a maximum in the red to infrared spectrum range; Active role of the...

  • Efficient polymer light-emitting diodes using conjugated polymer blends. He, Gufeng; Liu, Jie; Li, Yongfang; Yang, Yang // Applied Physics Letters;3/18/2002, Vol. 80 Issue 11, p1891 

    Photoluminescence studies have been performed on poly [2,5-bis(cheolestranoxy)-l,4-phenylene vinylene] (BCHA) blends with poly(9,9-dioctylfluorene) (PF). The composition-independent, distinctive emission of BCHA in the BCHA/PF blends suggests the nonexistence of interchain species in the blends,...

  • Light-emitting diodes using n-type conducting polymer: Poly(p-pyridyl vinylene). Onoda, Mitsuyoshi // Journal of Applied Physics;7/15/1995, Vol. 78 Issue 2, p1327 

    Presents a study which demonstrated the fabrication of light-emitting diodes (LED) using n-type conducting polymer. Discussion on the electroluminescent properties of the LED; Overview of previous studies on the application of conjugated polymers in LED; Details of experimental techniques used.

  • Thermal control of near-infrared and visible electroluminescence in alkyl-phenyl substituted.... Berggren, M.; Gustafsson, G. // Applied Physics Letters;9/19/1994, Vol. 65 Issue 12, p1489 

    Examines the electroluminescence of alkyl-phenyl substituted polythiophene. Advantages of polymeric electroluminescent devices over inorganic materials; Characteristics of low-bandgap form and high-bandgap form polymer films; Analysis on thermally treated polymer light emitting diodes.

  • Nanosecond transient electroluminescence from polymer light-emitting diodes. Braun, D.; Moses, D. // Applied Physics Letters;12/28/1992, Vol. 61 Issue 26, p3092 

    Examines the electroluminescence (EL) behavior of polymer light-emitting diodes (LED). Details on EL intensity at low-duty cycle pulses; Application of voltage pulses to LED; Display of thermochromism in the EL spectra and in semiconducting polymers.

  • Electroluminescence and electrical transport in poly(3-octylthiophene) diodes. Braun, D.; Gustafsson, G.; McBranch, D.; Heeger, A. J. // Journal of Applied Physics;7/15/1992, Vol. 72 Issue 2, p564 

    Presents a study which fabricated light-emitting diode structures using poly(3-octylthiophene) as the semiconductor polymer and presented the initial characterization of their electrical and electroluminescent properties. Experimental details; Device characteristics; Conclusions.

  • White light emission from single component polymers fabricated by spin coating. Tsai, Mu-Lin; Liu, Ching-Yang; Hsu, Ming-Ann; Chow, Tahsin J. // Applied Physics Letters;1/27/2003, Vol. 82 Issue 4, p550 

    A polymeric material prepared from single monomers is described, which emits white electroluminescence. The broad emission band is composed of a blue emission from anthracene and a red emission from aggregates. Single and double layer devices of light emitting diode were fabricated and examined.

  • Recombination kinetics in wide gap electroluminescent conjugated polymers with on-chain emissive defects. Nikitenko, V. R.; Lupton, J. M. // Journal of Applied Physics;5/15/2003, Vol. 93 Issue 10, p5973 

    We analyze the experimental dependence of temporally and spectrally resolved electroluminescence (EL) from polyfluorene-based light-emitting diodes on electric field and temperature. The blue band in the EL spectrum is caused by emission from the polymer backbone, while the low-energy green...

  • Mechanism of enhanced quantum efficiency in light-emitting diode based on a poly(p-phenylenevinylene) derivative. Jae Won Jang; Dong Keun Oh // Journal of Applied Physics;3/15/2000, Vol. 87 Issue 6, p3183 

    Deals with a study that investigated the transient electroluminescence characteristics of poly(p-phenylenevinylene) (PPV) to understand the carrier mobilities in the polymers. Opinion on PPV as a light-emitting organic polymer; Thickness of the indium-tin-oxide electrode used for hole injecting...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics