Green Phosphorescent OLED Without a Hole/Exciton Blocking Layer Using Intermixed Double Host and Selective Doping

Won-Ki Kim; Hyung-Seok Kim; Hyun-Kwan Shin; Ji-Geun Jang

Korean Journal of Materials Research, Vol.19, No.5, 240-244, May, 2009

DOI10.3740/MRSK.2009.19.5.240 Export Citation

Green Phosphorescent OLED Without a Hole/Exciton Blocking Layer Using Intermixed Double Host and Selective Doping

Won-Ki Kim, Hyung-Seok Kim, Hyun-Kwan Shin, and Ji-Geun Jang^†

Department of Electronics Engineering, Dankook University, Chungnam 330-714, Korea

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Simple and high efficiency green phosphorescent devices using an intermixed double host of 4, 4', 4''- tris(N-carbazolyl) triphenylamine [TCTA], 1, 3, 5-tris (N-phenylbenzimiazole-2-yl) benzene [TPBI], phosphorescent dye of tris(2- phenylpyridine)iridium(III) [Ir(ppy)3], and selective doping in the TPBI region were fabricated, and their electro luminescent characteristics were evaluated. In the device fabrication, layers of 70 A -TCTA/90 A -TCTA0.5TPBI0.5/90 A -TPBI doped with Ir(ppy)3 of 8% and an undoped layer of 50 A -TPBI were successively deposited to form an emission region, and SFC137 [proprietary electron transporting material] with three different thicknesses of 300 A, 500 A, and 700 A were used as an electron transport layer. The device with 500 A -SFC137 showed the luminance of 48,300 cd/m2 at an applied voltage of 10 V, and a maximum current efficiency of 57 cd/A under a luminance of 230 cd/m2. The peak wavelength in the electroluminescent spectral and color coordinates on the Commission Internationale de I’Eclairage [CIE] chart were 512 nm and (0.31, 0.62), respectively.

Keywords:green phosphorescent OLED;TCTA;TPBI;Ir(ppy)3;intermixed double host;selective doping

[References]

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[Referenced By]

[1] Lamansky S, Djurovich P, Murphy D, Abdel-Razzaq F, Lee HE, Adachi C, Burrows PE, Forrest SR, Thompson ME, J. Am. Chem. Soc., 123(18), 4304 (2001)

[2] Burroughs JH, Bradley DDC, Brown AR, Marks RN, Mackay K, Friend RH, Burn PL, Holmes AB, Nature., 347, 539 (1990)

[3] Baldo MA, Lamansky S, Burro-Ws PE, Thompson ME, Forrest SR, Appl. Phys. Lett., 75, 4 (1999)

[4] Kafafi ZH, Organic Electroluminescence, p. 1, ed., Thompson BJ, Taylor & Francis, New York, USA, (2005). (2005)

[5] Kern W, Thin Film Process II, p. 501, ed., Vossen JL, Academic Press, San Diego, USA, (2002). (2002)

[6] Wilson JS, Dhoot AS, Seeley AJAB, Khan MS, Kohler A, Friend RH, Nature, 413, 828 (2001)

[7] Lu W, Mi BX, Chan MCW, Hui Z, Che CM, Zhu NY, Lee ST, J. Am. Chem. Soc., 126(15), 4958 (2004)

[8] Matsushima H, Naka S, Okada H, Onnagawa H, Curr. Appl. Phys., 5(4), 305 (2005)

[9] Zhou X, Qin DS, Pfeiffer M, Blochwitz J, Werner A, Crechsel J, Maennig B, Leo K, Bold M, Erk P, Hartmann H, Appl. Phys. Lett., 81, 4070 (2002)

[10] He G, Pfeiffer M, Leo K, Hofmann M, Birnstock J, Pudzich R, Salbeck J, Appl. Phys. Lett., 85, 3911 (2004)

[11] Ikai M, Tokito S, Sakamoto Y, Suzuki T, Taga Y, Appl. Phys. Lett., 79, 156 (2001)

[12] Mitsuya M, Suzuki T, Koyama T, Shirai H, Satuki M, Taniguchi Y, Satsuki M, Suga S, Appl. Phys. Lett., 77, 3272 (2000)