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Characterization of white electroluminescent devices fabricated using conjugated polymer blends

Published online by Cambridge University Press:  03 March 2011

Do-Hoon Hwang*
Affiliation:
Department of Applied Chemistry, Kumoh National Institute of Technology, Kumi 730-701, Korea
Moo-Jin Park
Affiliation:
Department of Applied Chemistry, Kumoh National Institute of Technology, Kumi 730-701, Korea
Suk-Kyung Kim
Affiliation:
Department of Applied Chemistry, Kumoh National Institute of Technology, Kumi 730-701, Korea
Nam-Heon Lee
Affiliation:
Department of Physics, Inha University, Incheon 402-751, Korea
Changhee Lee
Affiliation:
School of Electrical Engineering and Computer Science, Seoul National University, Seoul 151-744, Korea
Yong-Bae Kim
Affiliation:
Liquid Crystal Research Center, Department of Chemistry, Kon-Kuk University, Seoul 143-701, Korea
Hong-Ku Shim
Affiliation:
Center for Advanced Functional Polymers, Department of Chemistry and School of Molecular Science (BK21), Korea Advanced Institute of Science and Technology, Taejon 305-701, Korea
*
a) Address all correspondence to this author. e-mail: dhhwang@kumoh.ac.kr
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Abstract

We report the characterization of white light emitting devices fabricated using conjugated polymer blends. Blue emissive poly[9,9-bis(4′-n-octyloxyphenyl)fluorene-2,7-diyl-co-10-(2′-ethylhexyl)phenothiazine-3,7-diyl] [poly(BOPF-co-PTZ)] and red emissive poly(2-(2′-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene) (MEH-PPV) were used in the blends. The inefficient energy transfer between these blue and red light emitting polymers (previously deduced from the photoluminscence (PL) spectra of the blend films) enables the production of white light emission through control of the blend ratio. The PL and electroluminescence (EL) emission spectra of the blend systems were found to vary with the blend ratio. The EL devices were fabricated in the indium tin oxide [poly(3,4-ethylenedioxy-thiophene)-poly(styrenesulfonate)] (ITO/PEDOT-PSS)blend/LiF/Al configuration, and white light emission was obtained for one of the tested blend ratios.

Type
Articles—Organic Electronics Special Section
Copyright
Copyright © Materials Research Society 2004

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References

REFERENCES

1.Wisnieff, R.: Display technology: Printing screens. Nature 394, 225 (1998).CrossRefGoogle Scholar
2.Shirringhaus, H., Tessler, N. and Friend, R.H.: Integrated optoelectronic devices based on conjugated polymers. Science 280, 1741 (1998).CrossRefGoogle Scholar
3.Katz, H.E., Bao, Z. and Gilat, S.L.: Synthetic chemistry for ultrapure, processable, and high-mobility organic transistor semiconductors. Acc. Chem. Res. 34, 359 (2001).CrossRefGoogle ScholarPubMed
4.Halls, J.J., Walsh, C.A., Greenham, N.C., Marseglia, E.A., Friend, R.H., Moratti, S.C. and Holmes, A.B.: Efficient photodiodes from interpenetrating polymer networks. Nature 376, 498 (1995).CrossRefGoogle Scholar
5.Prasad, P.N. and Williams, D.J.: Introduction to Nonlinear Effects in Monomers and Polymers, (John Wiley & Sons, New York, 1991)Google Scholar
6.Burroughes, J.H., Bradley, D.D.C., Brown, A.R., Marks, R.N., Mackay, K., Friend, R.H., Burn, P.L. and Holmes, A.B.: Light-emitting diodes based on conjugated polymers. Nature 347, 539 (1990).CrossRefGoogle Scholar
7.Gustafsson, G., Cao, Y., Treacy, G.M., Klavetter, F., Colaneri, N. and Heeger, A.J.: Flexible light-emitting diodes made from soluble conducting polymers. Nature 357, 477 (1992).CrossRefGoogle Scholar
8.Burn, P.L., Holmes, A.B., Kraft, A., Bradley, D.D.C., Brown, A.R., Friend, R.H. and Gymer, R.W.: Chemical tuning of electroluminescent copolymers to improve emission efficiencies and allow patterning. Nature 356, 47 (1992).CrossRefGoogle Scholar
9.Kraft, A., Grimsdale, A.C. and Holmes, A.B. Electroluminescent conjugated polymers-seeing polymers in a new light Angew. Chem. Int. Ed . 37, 402 (1998)3.0.CO;2-9>CrossRefGoogle Scholar
10.Mitschke, U. and Bäuerle, P.: The electroluminescence of organic materials. J. Mater. Chem. 10, 1471 (2000).CrossRefGoogle Scholar
11.Neher, D.: Polyfluorene Homopolymers: Conjugated liquid-crystalline polymers for bright blue emission and polarized electroluminescence. Macromol. Rapid. Commun. 22, 1365 (2001).3.0.CO;2-B>CrossRefGoogle Scholar
12.Scherf, U. and List, E.J.W.: Semiconducting polyfluorenes towards reliable structure-property relationships. Adv. Mater. 14, 477 (2002).3.0.CO;2-9>CrossRefGoogle Scholar
13.Pogantsch, A., Wenzl, F.P., List, E.J.W., Leizing, G., Grimsdale, A.C. and Müllen, K.: Polyfluorenes with dendron side chains as the active materials for polymer light-emitting devices. Adv. Mater. 14, 1061 (2002).3.0.CO;2-6>CrossRefGoogle Scholar
14.Cho, N.S., Hwang, D.H., Lee, J.I., Jung, B.J. and Shim, H.K.: Synthesis and color tuning of new fluorene-based copolymers. Macromolecules 35, 1224 (2002).CrossRefGoogle Scholar
15.Lee, J.H. and Hwang, D.H.: Alkoxyphenyl substituted polyfluorene; a stable blue light emitting polymer with good solution processibility. Chem. Commun. 00, 2836 (2003).CrossRefGoogle Scholar
16.Hwang, D.H., Kim, S.T., Shim, H.K., Holmes, A.B., Moratti, S.C. and Friend, R.H.: Green light-emitting diode from poly(2dimethyloctylsilyl-1,4-phenylenevinylene). J. Chem. Soc. Chem. Commun. 00, 2241 (1996).CrossRefGoogle Scholar
17.Becker, H., Spreitzer, H., Ibrom, K. and Kreuder, W.: New insights into the microstructure of GILCH-polymerized PPVs. Macromolecules. 32, 4925 (1999).CrossRefGoogle Scholar
18.Becker, H., Spreitzer, H., Kreuder, W., Kluge, E., Schenk, H., Parker, I. and Cao, Y.: Soluble PPVs with enhanced performance - a mechanistic approach. Adv. Mater. 12, 43 (2000).3.0.CO;2-F>CrossRefGoogle Scholar
19.Hwang, D.H. and Shim, H.K.Luminescence properties of a liquid crystalline poly[2,5-bis(dimethyloctylsilyl)-1,4-phenylenevinylene]. Thin Solid Film 417, 166 (2002).CrossRefGoogle Scholar
20.Hwang, D.H., Lee, J.D., Kang, J.M., Lee, S., Lee, C.H. and Jin, S.H.: Synthesis and light-emitting properties of poly(9,9-di-n-octylfluorenyl- 2,7-vinylene) and PPV copolymers. J. Mater. Chem. 13, 1540 (2003).CrossRefGoogle Scholar
21.Dodabalapur, A., Rothberg, L.J. and Miller, T.M.: Color variation with electroluminescent organic semiconductors in multimode resonant cavities. Appl. Phys. Lett. 65, 2308 (1994).CrossRefGoogle Scholar
22.Kido, J., Kimura, M. and Nagai, K.Multilayer white light-emitting organic electroluminescent device. Science 267, 1332 (1995).CrossRefGoogle ScholarPubMed
23.Deshpande, R.S., Bulovic, V. and Forrest, S.R.: White-light-emitting organic electroluminescent devices based on interlayer sequential energy transfer. Appl. Phys. Lett. 75, 888 (1999).CrossRefGoogle Scholar
24.Kido, J., Shionya, H. and Nagai, K.: Single-layer white light-emitting organic electroluminescent devices based on dye-dispersed poly( N -vinylcarbazole). Appl. Phys. Lett. 67, 2281 (1995).Google Scholar
25.Hwang, D.H., Lee, J.H., Lee, J.I., Lee, C.H. and Kim, Y.B.: White electroluminescent devices using polymer blends. Mol. Cryst. Liq. Cryst. 405, 127 (2003).CrossRefGoogle Scholar