scholarly journals Improvement of Quantum Dot Light Emitting Device Characteristics by CdSe/ZnS Blended with HMDS (Hexamethyldisilazane)

2020 ◽  
Vol 10 (17) ◽  
pp. 6081
Author(s):  
Junekyun Park ◽  
Eunkyu Shin ◽  
Jongwoo Park ◽  
Yonghan Roh
Keyword(s):  
Quantum Dot ◽  
Photoelectron Spectroscopy ◽  
Surface Defects ◽  
Hole Transport ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Hole Transport Layer ◽  
Atmospheric Conditions ◽  
Light Emitting ◽  
X Ray

We demonstrated the way to improve the characteristics of quantum dot light emitting diodes (QD-LEDs) by adding a simple step to the conventional fabrication process. For instance, we can effectively deactivate the surface defects of quantum dot (QD) (e.g., CdSe/ZnS core-shell QDs in the current work) with the SiO bonds by simply mixing QDs with hexamethyldisilazane (HMDS) under atmospheric conditions. We observed the substantial improvement of device characteristics such that the current efficiency, the maximum luminance, and the QD lifetime were improved by 1.7–1.8 times, 15–18%, and nine times, respectively, by employing this process. Based on the experimental data (e.g., energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS)), we estimated that the growth of the SiOx on the surface of QDs is self-limited: the SiOx are effective to passivate the surface defects of QDs without deteriorating the intrinsic properties including the color-purity of QDs. Second, we proposed that the emission profiling study can lead us to the fundamental understanding of charge flow in each layer of QD-LEDs. Interestingly enough, many problems related to the charge-imbalance phenomenon were simply solved by selecting the combination of thicknesses of the hole transport layer (HTL) and the electron transport layer (ETL).

High luminance of CuInS2-based yellow quantum dot light emitting diodes fabricated by all-solution processing

RSC Advances ◽  
2016 ◽  
Vol 6 (76) ◽  
pp. 72462-72470 ◽  
Author(s):  
Jingling Li ◽  
Hu Jin ◽  
Kelai Wang ◽  
Dehui Xie ◽  
Dehua Xu ◽  
...  
Keyword(s):  
Electron Transport ◽  
Quantum Dot ◽  
Zno Nanoparticles ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Hole Transport Layer ◽  
High Luminance ◽  
Light Emitting

In this work, all-solution processed, multi-layer yellow QLEDs, consisting of a hole transport layer of poly(9-vinylcarbazole), emissive layer of ligand exchanged CuInS2/ZnS QDs, and electron transport layer of ZnO nanoparticles, are fabricated.

All inorganic quantum dot light emitting devices with solution processed metal oxide transport layers

MRS Advances ◽  
2016 ◽  
Vol 1 (4) ◽  
pp. 305-310 ◽  
Author(s):  
R. Vasan ◽  
H. Salman ◽  
M. O. Manasreh
Keyword(s):  
Electron Transport ◽  
Quantum Dot ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Hole Transport ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Hole Transport Layer ◽  
Light Emitting ◽  
Light Emitting Devices

ABSTRACTAll inorganic quantum dot light emitting devices with solution processed transport layers are investigated. The device consists of an anode, a hole transport layer, a quantum dot emissive layer, an electron transport layer and a cathode. Indium tin oxide coated glass slides are used as substrates with the indium tin oxide acting as the transparent anode electrode. The transport layers are both inorganic, which are relatively insensitive to moisture and other environmental factors as compared to their organic counterparts. Nickel oxide acts as the hole transport layer, while zinc oxide nanocrystals act as the electron transport layer. The nickel oxide hole transport layer is formed by annealing a spin coated layer of nickel hydroxide sol-gel. On top of the hole transport layer, CdSe/ZnS quantum dots synthesized by hot injection method is spin coated. Finally, zinc oxide nanocrystals, dispersed in methanol, are spin coated over the quantum dot emissive layer as the electron transport layer. The material characterization of different layers is performed by using absorbance, Raman scattering, XRD, and photoluminescence measurements. The completed device performance is evaluated by measuring the IV characteristics, electroluminescence and quantum efficiency measurements. The device turn on is around 4V with a maximum current density of ∼200 mA/cm2 at 9 V.

scholarly journals Enhanced efficiency and high temperature stability of hybrid quantum dot light-emitting diodes using molybdenum oxide doped hole transport layer

RSC Advances ◽  
2019 ◽  
Vol 9 (28) ◽  
pp. 16252-16257 ◽  
Author(s):  
Jinyoung Yun ◽  
Jaeyun Kim ◽  
Byung Jun Jung ◽  
Gyutae Kim ◽  
Jeonghun Kwak
Keyword(s):  
High Temperature ◽  
Quantum Dot ◽  
Molybdenum Oxide ◽  
Temperature Stability ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Transport Layer ◽  
Stable Operation ◽  
High Temperature Stability ◽  
Light Emitting

QLEDs introducing a p-doped HTL exhibit stable operation at high temperature up to 400 K.

scholarly journals High-performance quantum dot light-emitting diodes with hybrid hole transport layer via doping engineering

2016 ◽  
Vol 24 (23) ◽  
pp. 25955 ◽  
Author(s):  
Qianqian Huang ◽  
Jiangyong Pan ◽  
Yuning Zhang ◽  
Jing Chen ◽  
Zhi Tao ◽  
...  
Keyword(s):  
Quantum Dot ◽  
High Performance ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Transport Layer ◽  
Light Emitting

scholarly journals All-inorganic quantum-dot light-emitting-diodes with vertical nickel oxide nanosheets as hole transport layer

2016 ◽  
Vol 26 (5) ◽  
pp. 503-509 ◽  
Author(s):  
Jiahui Li ◽  
Yuanlong Shao ◽  
Xuecheng Chen ◽  
Hongzhi Wang ◽  
Yaogang Li ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Nickel Oxide ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Transport Layer ◽  
Light Emitting

Degradation of Bilayer Organic Light-Emitting Diodes Studied by Impedance Spectroscopy

2016 ◽  
Vol 16 (4) ◽  
pp. 3368-3372 ◽  
Author(s):  
Shuri Sato ◽  
Masashi Takata ◽  
Makoto Takada ◽  
Hiroyoshi Naito
Keyword(s):  
Impedance Spectroscopy ◽  
Light Emitting Diodes ◽  
Device Simulation ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Hole Transport Layer ◽  
Light Emitting ◽  
Organic Light

The degradation of bilayer organic light-emitting diodes (OLEDs) with a device structure of N, N′-di(1-naphthyl)-N, N′-diphenylbenzidine (α-NPD) (hole transport layer) and tris-(8-hydroxyquinolate)aluminum (Alq3) (emissive layer and electron transport layer) has been studied by impedance spectroscopy and device simulation. Two modulus peaks are found in the modulus spectra of the OLEDs below the electroluminescence threshold. After aging of the OLEDs, the intensity of electroluminescence is degraded and the modulus peak due to the Alq3 layer is shifted to lower frequency, indicating that the resistance of the Alq3 layer is increased. Device simulation reveals that the increase in the resistance of the Alq3 layer is due to the decrease in the electron mobility in the Alq3 layer.

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