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A Study on the Dielectric Polarization of $ITO/Alq_3/Al$ Structure Organic Light-emitting Diodes  

Oh, Yong-Cheul (광운대학교 전기공학과)
Shin, Cheol-Gi (부천대 디지털산업전자과)
Kim, Chung-Hyeak (광운대학교 교양학부)
Publication Information
The Transactions of The Korean Institute of Electrical Engineers / v.57, no.1, 2008 , pp. 73-77 More about this Journal
Abstract
We have investigated dielectric polarization in organic light-emitting diodes using 8-hydroxyquinoline aluminum($Alq_3$) as an electron transport and emissive material. We analyzed the dielectric polarization of organic light-emitting diodes using characteristics of impedance and equivalent circuit of $ITO/Alq_3/Al$. Impedance characteristics was measured complex impedance Z and phase ${\theta}$ in the frequency range of $1{\times}40Hz\;to\;1{\times}10^8Hz$. We obtained complex electrical conductivity, dielectric constant, and loss tangent(tan${\delta}$) of the device at room temperature. And, we obtained the equivalent circuit of $ITO/Alq_3/Al$ through analyzing dielectric constant and dielectric loss tangent. From these analyses, we could interpret a conduction mechanism and dielectric polarization.
Keywords
OLEDs; $Alq_3$; Dielectric loss tangent(tan${\delta}$); Polarization;
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