Improving the charge balance and performance of CdSe/ZnS quantum-dot light-emitting diodes with a sputtered zinc-tin-oxide electron-transport layer and a thermally evaporated tungsten-oxide charge-restricting layer

Kim, Dong-Jin; Lee, Ho-Nyeon

doi:10.7567/1347-4065/ab3c77

Cited by 14 publications

(8 citation statements)

References 43 publications

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“…Micromachines 2022, 13, x FOR PEER REVIEW 3 of 7 worth, LA, USA). The energy levels of each layer were extracted via ultraviolet photoelectron spectroscopy (UPS) and ultraviolet-visible (UV-Vis) spectroscopy [23]. For UPS analysis, the AXIS Ultra DLD instrument (Kratos Analytical Ltd., Manchester, UK) was used.…”

Section: Resultsmentioning

confidence: 99%

“…The current-voltage-luminance (I-V-L) characteristics of the QLEDs were measured in a dark box using an I-V-L tester (Polaronix M6100IVL; McScience Inc., Suwon, Korea) combined with a spectroradiometer (Spectrascan-PR650; Photo Research Inc., Chatsworth, LA, USA). The energy levels of each layer were extracted via ultraviolet photoelectron spectroscopy (UPS) and ultraviolet-visible (UV-Vis) spectroscopy [23]. For UPS analysis, the AXIS Ultra DLD instrument (Kratos Analytical Ltd., Manchester, UK) was used.…”

Section: Methodsmentioning

confidence: 99%

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Flexible CdSe/ZnS Quantum-Dot Light-Emitting Diodes with Higher Efficiency than Rigid Devices

Kim

Kwon

et al. 2022

Micromachines

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Fabrication of high-performance, flexible quantum-dot light-emitting diodes (QLEDs) requires the reliable manufacture of a flexible transparent electrode to replace the conventional brittle indium tin oxide (ITO) transparent electrode, along with flexible substrate planarization. We deposited a transparent oxide/metal/oxide (OMO) electrode on a polymer planarization layer and co-optimized both layers. The visible transmittance of the OMO electrode on a polyethylene terephthalate substrate increased markedly. Good electron supply and injection into an electron-transporting layer were achieved using WOX/Ag/ WOX and MoOx/Ag/MoOX OMO electrodes. High-performance flexible QLEDs were fabricated from these electrodes; a QLED with a MoOX/Ag/ MoOX cathode and an SU-8 planarization layer had a current efficiency of 30.3 cd/A and luminance more than 7 × 104 cd/m2. The current efficiency was significantly higher than that of a rigid QLED with an ITO cathode and was higher than current efficiency values obtained from previously reported QLEDs that utilized the same quantum-dot and electron-transporting layer materials as our study.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Flexible CdSe/ZnS Quantum-Dot Light-Emitting Diodes with Higher Efficiency than Rigid Devices

Kim

Kwon

et al. 2022

Micromachines

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“…Each layer's energy band in QLED was obtained by combining the data from UPS and Tauc plot [29]. The cutoff energy of the secondary electron obtained from the UPS data is shown in Figure 3a, and the highest occupied molecular orbital (HOMO) energy level is shown in Figure 3b.…”

Section: Resultsmentioning

confidence: 99%

Substrate Dependence of CdSe/ZnS Quantum-Dot Light-Emitting Diodes: A Comparative Study between Rigid Glass and Flexible Plastic Substrates

2023

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The purpose of this study was to investigate the effect of substrate characteristics on the performance of quantum-dot light-emitting diodes (QLEDs) with the aim of developing high-performance flexible QLEDs. Specifically, we compared QLEDs made with a flexible polyethylene naphthalate (PEN) substrate to those made with a rigid glass substrate, using the same materials and structure except for the substrates. Our findings indicate that the PEN QLED had a 3.3 nm wider full width at half maximum and a 6 nm redshifted spectrum in comparison to the glass QLED. Additionally, the PEN QLED exhibited a 6% higher current efficiency, a flatter current efficiency curve, and a 2.25-V lower turn-on voltage, indicating superior overall characteristics. We attribute the spectral difference to the optical properties of the PEN substrate, such as light transmittance and refractive index. Our study also revealed that the electro-optical properties of the QLEDs were consistent with the electron-only device and transient electroluminescence results, which suggests that the improved charge injection properties of the PEN QLED were responsible. Overall, our study provides valuable insights into the relationship between substrate characteristics and QLED performance, which can be used to develop high-performance QLEDs.

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“…The foremost peak is the essential emission of PO-01 with a peak wavelength of 552 nm. The spectrum of the optimized nanocomposite layer device is much narrower than those of other devices owing to the microcavity effect of the device producing a high color purity of the emitted light. ,, …”

Section: Resultsmentioning

confidence: 99%

“…The spectrum of the optimized nanocomposite layer device is much narrower than those of other devices owing to the microcavity effect of the device producing a high color purity of the emitted light. 45,61,62 The optical absorbance and the transmittance of the films deposited on the ITO-sputtered glass substrates having a transmittance of over 98% in the visible region were measured. As expressed in Figure 6, the TPBi film exhibits a higher absorbance as compared to TiO 2 in the ultraviolet region from 350 to 300 nm and shows minimum absorbance in the visible region.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Nanocomposite Electron-Transport Layer Incorporated Highly Efficient OLED

Nagar

Shahnawaz

Yadav

et al. 2020

ACS Appl. Electron. Mater.

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The realization of highly efficient devices depends on efficient charge carrier injection, employment of materials, and proper fabrication methodologies. However, it is difficult to manufacture highly efficient large-area devices due to the varied thickness of organic layers and low mobility of charge carriers. Solution and thermal evaporation processes have been reported for the fabrication of highly efficient and long-lifetime organic light-emitting diodes (OLEDs). This work reveals appropriate performance enhancement by employing solution-processable nanocomposite, i.e., titanium oxide (TiO 2 ) nanoparticles embedded in 2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) as an electron-transport layer with high electron mobility and good compatibility with the yellow emissive layer. Topographies of TiO 2 -doped TPBi films with different doping concentrations are observed after annealing at 60 °C. The device using a 20 wt % TiO 2 -doped TPBi exhibits maximum power efficacy of 56.1 lmW −1 , current efficiency of 53.9 cdA −1 , and external quantum efficiency of 15.4%, while that without TiO 2 nanoparticles showed values of 37.0 lmW −1 , 35.1 cdA −1 , and 10.8%, respectively. The enhancement may be attributed to improved electron mobility, efficient hole-blocking, and reduced barrier height. The solution-processable TiO 2 -doped TPBi may lead to an efficient fabrication strategy for next-generation lighting and display applications.

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Improving the charge balance and performance of CdSe/ZnS quantum-dot light-emitting diodes with a sputtered zinc-tin-oxide electron-transport layer and a thermally evaporated tungsten-oxide charge-restricting layer

Cited by 14 publications

References 43 publications

Flexible CdSe/ZnS Quantum-Dot Light-Emitting Diodes with Higher Efficiency than Rigid Devices

Flexible CdSe/ZnS Quantum-Dot Light-Emitting Diodes with Higher Efficiency than Rigid Devices

Substrate Dependence of CdSe/ZnS Quantum-Dot Light-Emitting Diodes: A Comparative Study between Rigid Glass and Flexible Plastic Substrates

Nanocomposite Electron-Transport Layer Incorporated Highly Efficient OLED

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