| 1. |
- Berggren, Magnus, et al.
(författare)
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Green Electroluminescence in Poly-(3-cyclohexylthiophene) light-emitting diodes
- 1994
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Ingår i: Advanced Materials. - : Wiley-VCH Verlag Berlin. - 0935-9648 .- 1521-4095. ; 6:6, s. 488-490
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Tidskriftsartikel (refereegranskat)abstract
- Electoluminescent devices based on polythiophene-system this films have been demonstrated that together span the entire visible range, steric hindrance being used to vary the bandgap between compunds. Poly-(3-cyclohexylthiophene), see Figures, exhibits green electoluminescence. Possible interpretations of this observation are proposed.
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| 2. |
- Berggren, Magnus, et al.
(författare)
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Light-emitting diodes with variable colours from polymer blends
- 1994
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 372:6505, s. 444-446
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Tidskriftsartikel (refereegranskat)abstract
- THE range of materials now available for polymer-based light-emitting diodes (LEDs) is such that electroluminescence can be obtained throughout the visible spectrum(1-12). Here we show that, by blending polymers with different emission and charge-transport characteristics, LEDs can be fabricated in which the emission colour varies as a function of the operating voltage. This phenomenon arises from the self-organizing properties of the blends, in which entropy drives phase separation of the constituent polymers and gives rise to submicrometre-sized domains having a range of compositions and emission characteristics. Emission from domains of different composition is controlled by the ease with which charge is injected, which in turn depends on the applied voltage.
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| 3. |
- Berggren, Magnus, et al.
(författare)
-
Thermal control of near‐infrared and visible electroluminescence in alkyl‐phenyl substituted polythiophenes
- 1994
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 65:12, s. 1489-1491
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Tidskriftsartikel (refereegranskat)abstract
- We report electroluminescence from a regioregular alkyl-phenyl substituted polythiophene. The polymer film exists in two forms, giving widely different optical absorption, as well as photoluminescence and electroluminescence spectra. In the low-bandgap form, we observe high emission intensity centered at 1.55 eV (800 nm), well into the infrared, while the high-bandgap form gives a maximum at 1.85 eV (670 nm). The conversion from the high-bandgap form to the low-bandgap form can be done by thermal treatment of the polymer light emitting diodes.
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| 4. |
- Berggren, Magnus, et al.
(författare)
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White light from an electroluminescent diode made from poly[3(4‐octylphenyl)‐2,2′‐bithiophene] and an oxadiazole derivative
- 1994
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 76:11, s. 7530-7534
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Tidskriftsartikel (refereegranskat)abstract
- We report on an electroluminescent diode emitting red, green, and blue light simultaneously. The device is based on a thin polymer layer, poly[3‐(4‐octylphenyl)‐2,2′‐bithiophene] and a thick molecular layer, 2‐(4‐biphenylyl)‐5‐(4‐tertbutyl‐phenyl)1,3,5‐oxadiazole. The quantum efficiency for light conversion is 0.3% and the turn‐on voltage for light emission is 7 V. In this article we present electric and spectroscopic characterizations. A mechanism for the light emission, based on electron and hole recombination between the two organic layers, is proposed
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| 5. |
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