• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.05a
• /
• pp.128-131
• /
• 2004

유기발광소자(OLED)Glass/indium-tin-oxide(ITO)/Cu-Pc(copper-phthalocyanine)/N.N'-Bis(3-methylphenyl)-1,1'-biphenylbenzidine/tris-(8-hydroquinoline) aluminum(Alq3)/aluminum(Al)의 기본구조로 제작된 OLED에 다양한 전압을 인가하면서, 마이크로파 근접장 현미경을 이용하여 전압인가에 따른 반사계수(S11)와 소자의 전류-전압특성을 측정함으로써 전기적 전도 특성을 연구하였다. 또한 다양한 인가전압에 따른 EL(electro luminance)를 측정하여 소자의 광학적 특성과 전기적 특성을 연구 비교하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.351-352
• /
• 2008

A new high efficient red PhOLED using a host of $Bebq_2$ and double dopants of $(pq)_2$Ir(acac) and SEC-R411 have been fabricated and evaluated. The device doubly doped with $(pq)_2$Ir(acac) and SFC-R411 showed the current efficiency improvement of 22% under a luminance of 10000 cd/$m^2$ in comparision with the device singly doped with SFC-R411. The luminance, current efficiency and central wavelength of the doubly doped device were 9300 cd/$m^2$ at 7V, 11.1 cd/A under a luminance of 10000 cd/$m^2$ and 625 nm, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.04a
• /
• pp.107-110
• /
• 2003

본 연구에서는 캐소드 방향으로 발광하는 Top emission 소자를 설계 제작하였다. 이를 위하여 반투명한 금속 박막을 제작하여 전기적 특성과 광학적 특성을 비교 평가하였다. 이를 바탕으로 제작한 Top emission 소자를 bottom emission 소자와 비교하였을 때 구동 전압은 다소 높았으며 색좌표 및 스펙트럼이 이동하였는데 이동 정도와 경향성은 파장에 따라 다르게 나타났다

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.08a
• /
• pp.81-84
• /
• 2003

Conductive polyaniline(PANI)-camphosulfonic acid (CSA) film applied as a hole injection layer in ITO/PANI/P3HT/LiF/Al device. In the AFM images, electrochemically polymerized PANI-CSA films have the small particles and smooth sufficient for application as hole injection layer. By insertion of PANI-CSA buffer layer, the turn on voltage of ITO/PANI/P3HT/LiF/Al device lowed by 3V, whereas that of ITO/P3HT/LiF/Al device shows 5V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1998.06a
• /
• pp.253-257
• /
• 1998

Organic-based electroluminescent devices have attracted lots of interests because of their possible application as large-area flat pan디 display. In this study, current-voltage (I-V) characteristics of MEH-PPV thin films was investigated using various metal as a top electrode, where MEH-PPV thin films were prepared on 170 substrate by spin coating method and various metal such as Al, Ag, In, MgIn was deposited on MEH-PPV thin films as a top electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1997.11a
• /
• pp.163-166
• /
• 1997

Electroluminescent(EL) dcvice based on organic thin layers have attracted lots of interests because of thier possible application as large-area light-emitting displays. It was known that MEH-PPV and 1, 1, 4, 4, -Tetraphenyl-1, 3-butadiene(TPB) has red and blue emission peak at 580nm and 480nm, respectively. In this study, MEH-PPV films and TPB films were prepared by spin coating and vacuum deposition method, respectively. Films of MEH-PPV and TPB double layer were also prepared by the same method. Photoluminescent(PL) characteristics of these single and doubler layers were investigated, where a cell structure of glass substrate/ITO/MEH-PPV and/or TPB/Al was employed. It was found that the photoluminescent efficiency of TPB film was higher than that of MEH-PPV film with a single layer and also with a double structure. These films have also different I-V characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1997.11a
• /
• pp.328-330
• /
• 1997

Organic semiconductors such as conjugated polymers and oligomers have been studied many research groups. The band structures of conjugated polymers and oligomers are similar to those of conventional inorganic semiconductors Thin films based on these materials show a promising potential for Field Effect Transistors(FETs) and Light Emitting Diodes(LED) because fabrication processes are simple and cheaper for large electronic devices and flexible devices are also possible.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.12a
• /
• pp.114-118
• /
• 2006

We investigated the transient electroluminescence (EL) and modulation characteristics of red organic light-emitting diodes (OLEDs), which consist with 4-(dicyanomethylene)-2-i -propyl-6-(1,1,7,7-tetramethyljulolidyl-9-cnyl)-4H-pyran (DCJTI) and rubrene doped into tris(8-hydroxyquinoline)aluminum ($Alq_3$). The transient EL waveforms showed two components, the overshooting peak and constant component, indicating that the excess amount of accumulated charges simultaneously recombine at the onset moment. This overshooting effect reduced the rise time of transient EL and enhanced the optical output of OLEDs when the pulse voltage applied to the device. We demonstrated that the red OLEDs could be use for the high-speed switching application by driving at more than 100 MHz and transmitting the video signals utilized as the electro-optical conversion device

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.14 no.11
• /
• pp.922-927
• /
• 2001

Single-layer green ELs was fabricated with using molecularly-dispersed Bu-PBD into poly-N-vinylcarbazole(PVK) which has low operating voltage and high quantum efficiency. A EL cell structure of glass substrate/indium-tin-oxide/PVK:Bu-PBD:C6(∼ 100nm)/Ca(20nm)/Al(20nm) was employed with variable doping concentration. The keys to obtain high quantum efficiency was excellent film forming capability of molecularly dispersed into PVK and appropriate combination of cathode for avoiding exciplex. We obtained the turn-on voltage of 4.2V and quantum efficiency of 0.52% at 0.lmol% of C6 concentration which has been improved about a factor of 50 in comparison with the undoped cell. The PL peak wavelengths wouldn\`t be turned by changing the concentration of the C6 dopant. Green EL emission peak and FWHM were 520nm and 70nm respectively. PL emission peak was obtained at 495nm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.442-443
• /
• 2007

We have studied new hole blocking layer for effective organic light emitting diodes. The device having a structure of ITO/2TNATA/$\alpha$-NPD/DPVBi : Rubrene(0.7%)/DPVBi/New Hole Blocking layer or BCP/$Alq_3$/LiF/Al has been used. The driving voltage of OLED with BCP(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) or New HBL were 5.5V and 4.4V, respectively. As a result, new HBL rather than BCP has a good hole blocking ability.