• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.239-244
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• 2007

Highly efficient and stable white PIN OLED structures have been developed with a focus on possible AM display applications. Due to the use of the novel air-stable Novaled n-dopant material NDN26, the mass production compatibility of the PIN approach is improved. With both a conventional n-dopant, NDN1, and a novel air-stable n-dopant, NDN26, similar performance in efficiency and lifetime are reached. Based on highly a stable red fluorescent emitter system, the Novaled PIN approach allows for reaching ultra-long lifetimes of 1,000,000 hours at a brightness of $1,000\;cd/m^2$, both for top and for bottom emission layouts. Furthermore, inverted PIN structures for a possible use in a-Si backplane applications for AM displays are shown. With a phosphorescent green emitter system it could be demonstrated that for bottom and inverted as well as non-inverted top emission, a brightness of $1,000\;cd/m^2$ can be reached at below 3 V. In addition to low operating voltages and long lifetimes, PIN OLEDs also enable for device structures with extremely low operating voltage drifts, a feature of increasing importance for future AM display developments.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.824-827
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• 2004

High performance green $Ir(ppy)_3$-based phosphorescent OLEDs (PHOLEDs) have been fabricated by organic vapor phase deposition ($OVPD^{TM}$). In addition to demonstrating both efficiency and operational device lifetime comparable to devices built by vacuum thermal evaporation, we report on the controllability and stability of the $OVPD^{TM}$ process. Specifically, run-to-run and day-to-day deposition rate reproducibility of better than 2 % for three consecutive days is demonstrated.

• 한국전기전자재료학회논문지
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• 제22권11호
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• pp.974-979
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• 2009

We studied solution-processed single-layered phosphorescent organic light-emitting diodes (PHOLEDs), doped with ionic salt and treated with simultaneous electrical and thermal annealing. Because the simultaneous annealing causes the accumulation of salt ions at the electrode surfaces, the energy levels of the organic molecules are bent by the electric fields due to the adsorbed ions, i.e., the simultaneous annealing can induce the proper formation of an ionic p-i-n structure. As a result, an ionic p-i-n PHOLED with a peak luminescence of over ${\sim}35,000\;cd/m^2$ and efficiency of 27 cd/A was achieved through increased and balanced carrier-injections.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.454-457
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• 2008

We report the syntheses, photophysical properties and device performances of solution processible host material for green-phosphorescent OLEDs. The butterfly-shaped new host materials with nonconjugated linkage of carbazole and fluorene moieties have large triple energy band gap around 2.8 eV. All of the EL devices exhibited turn-on voltages in the range of 4.8-5.0 V. GH-4 exhibited the best performance with a maximum current efficiency and power efficiency of 21.1 cd/A and 7.9 lm/W.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.499-502
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• 2008

Effects of a dielectric capping layer on the luminous characteristics of top emitting organic light emitting diodes (TOLEDs) have been analyzed using a classical electromagnetic theory. Special attention was given to the influence of the cavity length on the effectiveness of the capping layer. The luminance characteristics of the TOLEDs influenced by the combined effects of the cavity length and the capping layer thickness. Furthermore, these combined effects also modify the emission spectrum and pattern of the TOLEDs, which result in the improvement of total luminance of the device, but no significant change in the device out-coupling efficiency.

• 세라미스트
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• 제22권3호
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• pp.218-229
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• 2019

The development of highly efficient thermally activated delayed fluorescence (TADF) materials is an active area of recent research in organic light emitting diodes (OLEDs) since the first report by Chihaya Adachi in 2011. Traditional fluorescent materials can harvest only singlet excitons, leading to the theoretically highest external quantum efficiency (EQE) of 5% with considering about 20% light out-coupling efficiency in the device. On the other hand, TADF materials can harvest both singlet and triplet excitons through reverse intersystem crossing (RISC) from triplet to singlet excited states. It could provide 100% internal quantum efficiencies (IQE), resulting in comparable high EQE to traditional rare-metal complexes (phosphorescent materials). Thanks to a lot of efforts in this field, many highly efficient TADF materials have been developed. This review focused on recent molecular design concept and optoelectronic properties of TADF materials for high efficiency and long lifetime OLED application.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1692-1696
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• 2006

Dopant and host molecules for charge transport layer in OLED have been developed. They enable implementation of the PIN OLED technology in mass production. We review the status of PIN OLED with main focus on top-emission structures and operation stability at elevated temperatures. A green phosphorescent top-emission device with 2.5 V operating voltage and 90 lm/W at 1000 $cd/m^2$ is presented. For a red top-emission device, lifetime exceeding 100,000 h at 500 $cd/m^2$ initial brightness is reported. Operational stability at $80^{\circ}C$ has been investigated. A lifetime of 17,000 h at 500 $cd/m^2$ has been achieved. Finally, we comment on further reduction of the operating voltage in OLED.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.964-967
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• 2005

The search for stable electron transporters and hole injectors has become particularly intense over the last 18 months as OLED manufacturers are poised to start production of OLED panels. We report here a proprietary electron transporter (E246), which reduces the operating voltage, increases the efficiency and the lifetime of OLEDs made of fluorescent or phosphorescent systems when compared with Alq3 as an electron transporter. We also report a novel proprietary hole injector (buffer, E9363) which also reduces the operating voltage, increases the efficiency and doubles the lifetime compared to CuPC. These two materials are now available commercially for display manufacturers.

• 한국전기전자재료학회논문지
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• 제26권9호
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• pp.682-685
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• 2013

We have fabricated blue phosphorescent organic light-emitting devices (OLEDs) on a plastic substrate. The solution coated poly (9-vinylcarbazole) (PVK) host doped with Bis (3,5-difluoro-2-(2-pyridyl)phenyl_(2-carboxypyridyl)irdium(III) (FIrPic) guest molecules was used as an hole transporting emission layer. The device structure was ITO/PVK:FIrpic (50 nm, xwt%)/TAZ 50 nm)/LiF (0.5 nm)/Al (100 nm). The concentration of FIrpic molecule was varied from 1 wt% to 10 wt%. The OLED on plastic substrate exhibited maximum current efficiency of 18 cd/A with 5 wt% FIrpic molecules were doped into the PVK layer.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.58-61
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• 2007

We present simulations and results to demonstrate the viability of stainless steel foil as a substrate for low power consumption, flexible AMOLED displays. Using organic planarization layers, we achieve very smooth surface properties, resulting in excellent TFT performance, that can be repetitively flexed without significantly affecting device performance. The use of phosphorescent OLEDs enables the design of low power consumption 40" AMOLED displays.