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http://dx.doi.org/10.4313/TEEM.2005.6.3.091

Red Organic Light-emitting Diodes utilizing Energy Transfer and Charge Trapping

Kim, Ju-Seung (Center for Advanced Science and Innovation, Osaka University)
Gu, Hal-Bon (Department of Electrical Engineering, Chonnam National University)

Publication Information

Transactions on Electrical and Electronic Materials / v.6, no.3, 2005 , pp. 91-96 More about this Journal

Abstract

We report the efficient red light-emitting diodes based on the fluorescent dye 4-(dicyanomethylene)-2-i-propyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTI) and 5,6,11,12-tetraphenyl naphthacene (rubrene) codoped in the tris(8-hydroxyquinoline)aluminum $(Alq_3)$ . Luminance efficiency of 2.2 cd/A with a Commission International De L'Eclairage (CIE) chromaticity coordinate of x, y = (0.640, 0:350) are achieved at the driving current density of $20\;mA/cm^2$ . Adding the rubrene to the DCJTI in tris(8-hydroxyquinoline)aluminum $(Alq_3)$ , the red color purity and luminance efficiency improved comparing to the DCJTI only doped devices because the rubrene molecules assist the polarization effect of DCJTI by molecular interaction and enhance the energy transfer from $(Alq_3)$ to DCJTI.

Keywords

OLED; Carrier trapping; Energy transfer; Emitting assist dopant;

Citations & Related Records

Reference

1	J. Kido, H. Hayase, K. hongawa, K. Okuyama, K. Nagai, and K. Okuyama, 'Bright red light-emitting organic electroluminescent devices having a europium complex as an emitter', Appl. Phys. Lett., Vol. 64, p. 815,1994
2	R. A. Campos, L P. Kovlev, Y. Guo, N. Wakili, and T. Skotheim, 'Red electroluminescence from a thin organometallic layer of europium'. J. Appl. Phys., Vol. 80, p. 7144. 1996 DOI ScienceOn
3	Y. Hamada, H. Kanno, T. Tsujioka, H. Takahashi, and T. Usuki, 'Red organic light-emitting diodes using an emitting assist dipant', Appl. Phys. Lett., Vol. 75, No. 12, p. 1682, 1999
4	J. Feng, F. Li, W. Gao, G. Cheng, W. Xie, and S. Liu, 'Improvement of efficiency and color purity utilizing two-step energy transfer for red organic light-emitting devices', Appl. Phys. Lett., Vol. 81, p. 2935,2002
5	T.-H. Liu, C.-Y. Iou. s.w Wen. and C. H. Chen, '4( Dicyanomethylene)-2-t-butyl-6-( 1,1,7,7-tetramethyljulolidyl- 9-enyl)-4H-pyran doped red emitters in organic light-emitting devices', Thin Solids Films, Vol. 441,p. 223, 2003
6	F. Li, J. Lin, J. Feng, G. Cheng, H. Liu, S. Liu, L. Zhang, X. Zhang, and S. T. Lee, 'Electrical and optical characteristics of red organic light-emitting diodes doped with two guest dyes', Synth. Met., Vol. 139, p. 341, 2003
7	B. Balaganesan, S.-W. Wen, and C. H. Chen, 'Synthetic study of tetramethyljulolidine - a key intermediate toward the synthesis of the red dopant DCJTB for OLED application', Tetrahedron Letters, Vol. 44, p. 145,2003
8	C. H. Chen, C. W. Tang, J. Shi, and K. P. Klubek, 'Recent developments in the synthesis of red dopants for $Alq_3$ , hosted electroluminescence', Thin Solid films, Vol. 363, p. 327, 2000
9	S. V. Bulovic, R. Deshpande, M. E. Thompson, and S. R. Forrest, 'Funning the color emission of thin film molecular organic light emitting devices by the solid state solvation effect', Chem. Phys. Lett., Vol. 308, p. 317, 1999
10	R. N. Bera, Y. Sakakibara, M. Tokumoto, and K. Yase, 'Time-rcdolved photoluminescence study on energy transfer from $Alq_3$ ,(tris(8-hydroxyquinoline) aluminum) to red emissive tetraphenylchlorin', Jpn. J. Appl. Phys., Vol. 42, No.12, p. 7379, 2003 DOI
11	T. Yasuda, Y. Yamaguchi, De-Chun Zou, and T. Tsutsui, 'Carrier mobilities in organic electron transport materials determined from space charge limited current', Jpn. J. Appl. Phys., Vol. 41, No.9, p. 5626, 2002
12	S. Naka, H. Okada, H. Onnagawa, Y. Yamaguchi, and T. Tsutsui, 'Carrier transport properties of organic materials for EL device operation', Synth. Met., Vol. 111-112, p. 331, 2000
13	Z. Y. Xie, L. S. Hung, and S. T. Lee, 'Highefficiency red electroluminescence from a narrow recombination zone confined by an organic double heterostructure', Appl. Phys. Lett., Vol. 79, p. 1048, 2001 DOI ScienceOn