The influence of charge carriers in the hole transport layer on stability of quantum dot light-emitting devices

2021 ◽  
Author(s):  
Tyler Davidson-Hall ◽  
Hany Aziz
Keyword(s):  
Quantum Dot ◽  
Hole Transport ◽  
Charge Carriers ◽  
Transport Layer ◽  
Hole Transport Layer ◽  
Light Emitting ◽  
Light Emitting Devices

scholarly journals Optimization of the electron transport layer in quantum dot light-emitting devices

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Gary Zaiats ◽  
Shingo Ikeda ◽  
Prashant V. Kamat
Keyword(s):  
Electron Transport ◽  
Quantum Dot ◽  
Charge Carrier ◽  
Hole Transport ◽  
Charge Carriers ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Mobility Of Charge Carriers

AbstractQuantum dot light-emitting devices have emerged as an important technology for display applications. Their emission is a result of recombination between positive and negative charge carriers that are transported through the hole and electron conductive layers, respectively. The selection of electron or hole transport materials in these devices not only demands the alignment of energy levels between the layers but also balances the flow of electrons and holes toward the recombination sites. In this work, we examine a method for device optimization through control of the charge carrier kinetics. We employ impedance spectroscopy to examine the mobility of charge carriers through each of the layers. The derived mobility values provide a path to estimate the transition time of each charge carrier toward the emitting layer. We suggest that an optimal device structure can be obtained when the transition times of both charge carriers toward the active layer are similar. Finally, we examine our hypothesis by focusing on thickness optimization of the electron transport layer.

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 Widely applicable phosphomolybdic acid doped poly(9-vinylcarbazole) hole transport layer for perovskite light-emitting devices

RSC Advances ◽  
2019 ◽  
Vol 9 (52) ◽  
pp. 30398-30405
Author(s):  
Yanting Wu ◽  
Zewu Xiao ◽  
Lihong He ◽  
Xiaoli Yang ◽  
Yajun Lian ◽  
...  
Keyword(s):  
Phosphomolybdic Acid ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Injection ◽  
Hole Transport Layer ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Wide Range ◽  
Selection Of ◽  
Range Selection

Perovskite light-emitting devices using a PVK:PMA hole transport layer show robust performance, allowing the wide range selection of antisolvents and hole injection layers.

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).

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