Skip to main content Accessibility help

Materials Engineering For Polarized Light Emitting Diodes

  • G. Wegner (a1), D. Neher (a1), M. Remmers (a1), V. Cimrova (a1) and M. Schulze (a1)...


Electroluminescent devices have been made from organo-soluble derivatives of poly(pphenylene). Solubility and processibility by the LB-technique is achieved by attaching alkoxy side groups to the backbone-p-phenylene units. These polymers are of the hairy-rod (HR) type. If transferred as monolayers from the air-water-interface, monodomain multilayers with large order parameters of chain orientation are obtained. A 130 nm thick LB-film of poly(2,5-diisopentoxy-pphenylene) shows blue photoluminescence at λmax = 3.08 eV (404 nm) with a tail extending to 2 eV. The anisotropy was (lII- l1)/ (l11, + l11)= 0.5. This LB-film between a transparent gold and an evaporated Al-electrode shows polarized light emission at E ≤ 6.107 V cm−1 with am=a λmax2.2 eV and an in-plane anisotropy of 0.54. Thin films obtained by spincoating of the same polymer show isotropic electroluminescence between ITO and Al-electrodes with an external quantum efficiency of about 0.03 %. Higher efficiencies up to 4 % were realized optimizing the device architecture and the electrodes. Photocrosslinkable sites are introduced as side groups to the poly(pphenylene) chain. This allows patterning of the LEDs. General features of the supramolecular architecture and typical defect structures occurring in films of polyconjugated macromolecules are discussed using prototypical polymers as examples. Important effects are chain segregation according to chain length and formation of disclinations.



Hide All
1. Stamm, M., Fischer, E.W., Dettenmaier, M., Convert, P., Farad. Disc. Chem. Soc. 68, p. 263 (1979)
2. Wang, W., Lieser, G., Wegner, G., Liq. Cryst. 15, P 1 (1993)
3. Wang, W., Lieser, G., Wegner, G., Macromolecules 27, p. 1027 (1994)
4. Witteler, H., Lieser, G., Wegner, G., Schulze, M., Macromol. Chem. Rapid Commun. 14, p. 471 (1993)
5. Wegner, G., Thin Solid Films 216, p. 105 (1992)
6. Wegner, G., Mol. Cryst. Liq. Cryst. 235, p. 1 (1993)
7. Schwiegk, S., Vahlenkamp, Th., Xu, Y., Wegner, G., Macromolecules 25, p. 2513 (1992)
8. Wu, J.H., Lieser, G., Wegner, G., Adv. Mater. (1995) in press
9. Rehan, M., Schlüter, A.D., Wegner, G., Feast, J., Polymer 30, p. 1060 (1989)
10. Th. Vahlenkamp, Wegner, G., Macromol. Chem. Phys. 195, p. 1933 (1994)
11. Cimrova, V., Remmers, M., Neher, D., Wegner, G., Adv. Mater. (1995) in press
12. Rauscher, U., Bassler, H., Bradley, D.D.C., Hennecke, M., Phys. Rev. B 42, p. 9830 (1990)
13. Braun, D., Staring, E.G.J., CJ, R..Demandt, E., Rikken, G.L.J., Kessener, Y.A.R.R., Venhuizen, A.H.J., Synth. Met. 66, p. 75 (1994)
14. Brown, A.R., Greenham, N.C., Burroughes, J.H., Bradley, D.D.C., Friend, R.H., Burn, P.L., Kraft, A., Holmes, A.B., Chem. Phys. Lett. 200, p. 46 (1992)
15. Yokoyama, H., Science 256, p. 66 (1992)
16. Wittmann, H.F., Gruner, J., Friend, R.H., Spencer, G.W.C., Moratti, S.C., Holmes, A.B., Adv. Mat. 7, p. 541 (1995)
17. Cimrova, V., Neher, D., Synth. Meth., in press
18. Tsutsui, T., Takada, N., Saito, S., Ogino, E., Appl. Phys. Lett. 65, p. 1868 (1994)
19. Dodabalapur, A., Rothberg, L.J., Miller, T.M., Kwock, E.W., Appl. Phys. Lett. 64, p. 2486(1994)
20. Lemmer, U., Hennig, R., Guss, W., Ochse, A., Pommerehne, J., Sander, R., Greiner, A., Mahrt, R.F., Bassler, H., Fledmann, J., Gobel, E.O., Appl. Phys. Lett. in press
21. Cimrova, V., Neher, D., J. Appl. Phys., in press

Materials Engineering For Polarized Light Emitting Diodes

  • G. Wegner (a1), D. Neher (a1), M. Remmers (a1), V. Cimrova (a1) and M. Schulze (a1)...


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed