Journal of the Semiconductor & Display Technology (반도체디스플레이기술학회지)

The Korean Society Of Semiconductor & Display Technology (한국반도체디스플레이기술학회)
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Properties of Polymer Light Emitting Diodes Using PFO : MEH-PPV Emission Layer and Hole Blocking Layer

PFO : MEH-PPV 발광층과 정공 차단층을 이용한 고분자 발광다이오드의 특성

  • Lee, Hak-Min (Department of Electronic and Electrical Engineering, Dankook University) ;
  • Gong, Su-Cheol (Department of Electronic and Electrical Engineering, Dankook University) ;
  • Shin, Sang-Bae (Department of Electronic and Electrical Engineering, Dankook University) ;
  • Park, Hyung-Ho (Department of Ceramics Engineering, Yonsei University) ;
  • Jeon, Hyeong-Tag (Division of Materials Science and Engineering, Hanyang University) ;
  • Chang, Ho-Jung (Department of Electronic and Electrical Engineering, Dankook University)
  • Published : 2008.06.30
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Abstract

The yellow base polymer light emitting diodes(PLEDs) with double emission and hole blocking layers were prepared to improve the light efficiency. ITO(indium tin oxide) and PEDOT : PSS[poly(3,4-ethylenedioxythiophene) : poly(styrene sulfolnate)] were used as cathode and hole transport materials. The PFO[poly(9,9-dioctylfluorene)] and MEH-PPV[poly(2-methoxy-5(2-ethylhe xoxy)-1,4-phenylenevinyle)] were used as the light emitting host and guest materials, respectively. TPBI[Tpbi1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene] was used as hole blocking layer. To investigate the optimization of device structure, we prepared four kinds of PLED devices with different structures such as single emission layer(PFO : MEH-PPV), two double emission layer(PFO/PFO : MEH-PPV, PFO : MEH-PPV/PFO) and double emission layer with hole blocking layer(PFO/PFO : MEH-PPV/TPBI). The electrical and optical properties of prepared devices were compared. The prepared PLED showed yellow emission color with CIE color coordinates of x = 0.48, y = 0.48 at the applied voltage of 14V. The maximum luminance and current density were found to be about 3920 cd/$m^2$ and 130 mA/$cm^2$ at 14V, respectively for the PLED device with the structure of ITO/PEDOT : PSS/PFO/PFO : MEH-PPV/TPBI/LiF/Al.

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