• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.229.1-229.1
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• 2016

본 연구에서는 Hole Transporting Layer(HTL)와 Electron Transporting Layer(ETL)의 두께에 의한 특성을 비교해보기 위해서 각각 0, 10, 20 nm로 HTL, ETL 두께를 달리한 형광 OLED소자를 제작하였다. ETL의 두께가 얇아질수록 $V_{TH}$ 값은 2.5V에서 0.9 V로 낮게 나타났고 소자의 전체 두께와 on voltage는 비례한다는 특성을 발견할 수 있었다. HTL과 ETL이 두꺼울수록 각 layer에서 carrier들의 이동에 delay가 생기고 emission layer에서 표면까지 거리가 생기기 때문이다. ETL의 두께가 두꺼울수록 높은 luminance 값을 나타내는 차이를 보여주고 있다. Hole에 비해 이동도가 작은 electron은 emission layer까지 늦게 전달되어, EML내에서 비교적 cathode쪽에 가까운 곳에서 exciton이 형성되기 때문이다. CE에도 더 두꺼운 ETL을 가진 소자가 더 높은 CE값 가짐을 확인할 수 있다. 모든 소자가 $200mA/cm^2$에서 가장 높은 CE값을 나타낸 이유는 $200mA/cm^2$에서 electron-hole 결합이 만들어내는 exciton형성이 가장 많기 때문이다. PE, QE도 ETL 두께가 두꺼울수록 특성을 향상이다. 결론적으로 ETL의 두꺼울수록 current density값이 감소함을 보이고 있는 반면 turn on voltage, luminance, efficiency 증가함을 볼 수 있다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04a
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• pp.76-77
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• 2009

In this paper, We have studied Electron Transport Layer(ETL) in the New Organics applied to Red phosphorescent organic light-emitting devices. The structure of ITO/2-TNATA(15nm)/CBP;$Ir(piq)_3$/DPVBi(30nm)/New ETL(60nm)/LiF(0.5nm)/Al(100nm) has been used, measured changing doping concentration of EML. The results of OLED turn-on voltage at 2.2V, and Maximum Luminance at 2.8V was $1000cd/m^2$. This high luminance at low voltage results from a high electron. conduction of the new electron transport layer.

• Journal of the Semiconductor & Display Technology
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• v.7 no.3
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• pp.5-9
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• 2008

New devices with structure of ITO/2TNATA/NPB/TCTA/CBP:7%Ir(ppy)$_3$/BCP/ETL/LiF/Al were proposed to develop high luminous green phosphorescent organic light emitting diodes and their electroluminescent properties were evaluated. The experimental devices were divided into two kinds according to the material ($Alq_3$ or SFC137) used as an electron transport layer (ETL). Luminous intensities of the devices using $Alq_3$ and SFC137 as electron transport layers were 27,500 cd/$m^2$ and 51,500 cd/$m^2$ at an applied voltage of 9V, respectively. The current efficiencies of both devices were similar as 12.6 cd/A under a luminance of 10,000 cd/$m^2$, while showed slower decay in the device with SFC137 as an ETL according to the further increase of luminance. Current density and luminance of the device with SFC137 as an electron transport layer were higher at the same voltage than those of the device with $Alq_3$ as an ETL.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.37-38
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• 2008

In this paper, we have developed Organic light-emitting devices(OLEDs) using various thicknesses of new electron transport layer. The device structure of ITO/ 2-TNATA(15nm)/ DPVBi(40nm)/ New ETL(20nm,60nm,100nm)/ LiF(0.5nm)/Al(100nm) has been used. The operating voltage of the device was almost independent of the new ETL thickness, due to its high electron conducting property. For example, the operating voltages of the devices with 20nm and 60nm layers are almost 5V at a current density $200mA/cm^2$. The device with the new ETL shows the low turn-on of 2.5V.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.93-97
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• 2022

We report highly efficient quantum dot light-emitting diodes (QLEDs) with TiO₂ nanoparticles (NPs) as an alternative electron transport layer (ETL) and poly (methyl methacrylate) (PMMA) as an insulating layer. TiO₂ NPs were applied as ETLs of inverted structured QLEDs and the effect of the addition of PMMA between ETL and emission layer (EML) on device characteristics was studied in detail. A thin PMMA layer supported to make the charge balance in the EML of QLEDs due to its insulating property, which limits electron injection effectively. Green QLEDs with a PMMA layer produced the maximum luminance of 112,488 cd/m² and a current efficiency of 25.92 cd/A. We expect the extended application of TiO₂ NPs as the electron transport layer in inverted structured QLEDs device in the near future.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1410-1412
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• 2005

We present that the electroluminescence (EL) efficiency can be improved by doping an electron transport layer (ETL) with organic materials which can make electron current increase. The electron transport layer of aluminum tris(8 -hydroxyquinoline) (Alq3) is doped with 2-(4-Biphenylyl)-5-(4-tertbutylphenyl)- 1,3,4-oxadiazole) (butyl-PBD) to enhance the electron mobility of the ETL. The higher quantum efficiency of device having ETL using Alq3 doped with butyl-PBD can be attributed to the improved electron and hole balance.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.710-713
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• 2002

In order to improve the power efficiency of multi-layer organic light emitting diodes (OLEDs), electron injection into ETL(electron transport layer) from cathode at the interface between ETL and cathode was enhanced by interposing a proper electron injection layer at the interface. The HTL(hole transport layer) and ETL materials used were N, N'diphenyl- N, N' - bis(3-methylphenyl-1, 1'- biphenyl - 4, 4 'diamine (TPD) and tris (8-hydroxyquinoline) aluminum ($Alq_3$) respectively. Cathodes using co-evaporated Al-CsF, Al-KF, and Al-NaF composites are adopted to enhance the electrical and optical properties of OLEDs. OLEDs with alkaline metal-doped cathode show a luminance of as high as 35,000 cd/$m^2$, and external quantum efficiency about 1.35 %. In addition, they show higher power efficiency at all bias conditions and good reproducibility.

• Korean Journal of Materials Research
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• v.33 no.11
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• pp.475-481
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• 2023

Recently, the electron transport layer (ETL) has become one of the key components for high-performance perovskite solar cell (PSC). This study is motivated by the nonreproducible performance of ETL made of spin coated SnO₂ applied to a PSC. We made a comparative study between tin oxide deposited by atomic layer deposition (ALD) or spin coating to be used as an ETL in N-I-P PSC. 15 nm-thick Tin oxide thin films were deposited by ALD using tetrakisdimethylanmiotin (TDMASn) and using reactant ozone at 120 ℃. PSC using ALD SnO₂ as ETL showed a maximum efficiency of 18.97 %, and PSC using spin coated SnO₂ showed a maximum efficiency of 18.46 %. This is because the short circuit current (Jsc) of PSC using the ALD SnO₂ layer was 0.75 mA/cm² higher than that of the spin coated SnO₂. This result can be attributed to the fact that the electron transfer distance from the perovskite is constant due to the thickness uniformity of ALD SnO₂. Therefore ALD SnO₂ is a candidate as a ETL for use in PSC vacuum deposition.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.513-516
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• 2008

The luminance efficiency of the red organic light-emitting devices fabricated utilizing a double electron transport layer (ETL) consisting of an Al-doped and an undoped layer was investigated. The Al atoms existing in the ETL acted as hole blocking sites, resulting in an increase in the luminance efficiency.

• Current Photovoltaic Research
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• v.9 no.1
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• pp.1-5
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• 2021

The properties of the electron transport layer (ETL) have a great effect on perovskite solar cell performance. Depositing conformal SnO2 ETL on bottom textured silicon cells is essential to increase current density in terms of the silicon-perovskite tandem solar cells. In the recent study, the SnO2 electron transport layer deposited by the sputtering method showed an efficiency of 19.8%. Also, an electron transport layer with a sputtered TiO2 electron transport layer in a 4-terminal tandem solar cell has been reported. In this study, we synthesized SnOx ETL with a various sputtering power range of 30-60W by Radio-frequency (RF)-magnetron sputtering. The properties of SnOx thin film were characterized using ellipsometer, UV-vis spectrometer, and IV measurement. With a sputtering power of 50W, the solar cell showed the highest efficiency of 13.3%, because of the highest fill factor by the conductivity of SnOx film.