Electroluminescent Quantum Dot Light-Emitting Diodes with ZnO and MoO3 Carrier Transport Layers

2013 ◽  
Vol 677 ◽  
pp. 98-102 ◽  
Author(s):  
Chun Yuan Huang ◽  
Ping Hua Tsai ◽  
Ying Chih Chen ◽  
Hsin Chieh Yu ◽  
Yan Kuin Su
Keyword(s):  
Quantum Dot ◽  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Sol Gel ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Injection ◽  
Electron Transport Layer ◽  
Device Structure ◽  
Light Emitting

In this article, the quantum dot (QD) light emitting diodes (QDLEDs) with ZnO electron transport layer (ETL) and MoO3hole transport layer (HTL) were demonstrated. The ZnO ETL was fabricated by sol-gel method. To achieve balanced electron and hole injection, hole transport materials including 4,4'-di(N-carbazolyl)biphenyl (CBP) and MoO3were also adapted. The device structure can be simply depicted as indium tin oxide (ITO)/ZnO/Cs2CO3/QD/CBP/MoO3/Au. It was found that the Cs2CO3played an important role to facilitate radiative recombination and reduce the leakage current due to the poor quality of sol-gel fabricated ZnO thin film. Via inserting an annealed Cs2CO3buffer layer with proper thickness, red-emitting QDLEDs with low luminance turn-on voltage of 4.1 V and luminance larger than 100 cd/m2could be obtained. With our demonstration, QDLEDs with ZnO ETL can be a promising device structure for realizing QDLED’s commerizing.

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.

scholarly journals Regulation of hole transport layer for perovskite quantum dot light-emitting diodes

2021 ◽  
Vol 245 ◽  
pp. 03021
Author(s):  
Ronghong Zheng ◽  
Dong Huang ◽  
Dongyang Shen ◽  
Chengzhao Luo ◽  
Yu Chen
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Injection ◽  
Hole Transport Layer ◽  
Emission Layer ◽  
Light Emitting ◽  
Hole Injection Layer

Perovskite quantum dots have been widely used in light-emitting diodes (LEDs) because of their adjustable color, high quantum yield and easy solution processing. Furthermore, matching energy levels of device plays a profound role in the resultant LEDs. In this study, a polymeric material, namely poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4’-(N-(pbutylphenyl))diphenylamine)] (TFB), is introduced between the quantum dot emission layer and the hole injection layer PEDOT:PSS, which not only prevents the fluorescence quenching caused by the direct contact between the perovskite layer and the hole injection layer, but also reduces hole injection barrier, both being beneficial to the device performance. The optimal thickness of TFB has been obtained by adjusting the rotational speed and precursor solution concentration during spin coating. The optimized quantum dots LED has a switching on voltage of about 2.2 V, a maximum brightness of 4300 cd/m2, a maximum external quantum efficiency of 0.15%, and a maximum current density of 0.54 cd/A.

scholarly journals High efficiency green InP quantum dot light-emitting diodes by balancing electron and hole mobility

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Wei-Chih Chao ◽  
Tzu-Hsuan Chiang ◽  
Yi-Chun Liu ◽  
Zhi-Xuan Huang ◽  
Chia-Chun Liao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Hole Mobility ◽  
Hole Transport ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Light Emitting ◽  
A Current

AbstractThe industrialization of quantum dot light-emitting diodes (QLEDs) requires the use of less hazardous cadmium-free quantum dots, among which ZnSe-based blue and InP-based green and red quantum dots have received considerable attention. In comparison, the development of InP-based green QLEDs is lagging behind. Here, we prepare green InP/ZnSe/ZnS quantum dots with a diameter of 8.6 nm. We then modify the InP quantum dot emitting layer by passivation with various alkyl diamines and zinc halides, which decreases electron mobility and enhances hole transport. This, together with optimizing the electron transport layer, leads to green 545 nm InP QLEDs with a maximum quantum efficiency (EQE) of 16.3% and a current efficiency 57.5 cd/A. EQE approaches the theoretical limit of InP quantum dots, with an emission quantum yield of 86%.

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.

Hole injection of quantum dot light-emitting diodes facilitated by multilayered hole transport layer

2021 ◽  
Vol 558 ◽  
pp. 149944
Author(s):  
Jeong Ha Hwang ◽  
Junmo Kim ◽  
Byong Jae Kim ◽  
Myeongjin Park ◽  
Yong Woo Kwon ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Injection ◽  
Hole Transport Layer ◽  
Light Emitting

Fabrication of Micro-OLEDs by Room-temperature Curing Nanocontact-print Lithography Using DLC Molds

2012 ◽  
Vol 1511 ◽  
Author(s):  
Ippei Ishikawa ◽  
Keisuke Sakurai ◽  
Shuji Kiyohara ◽  
Taisuke Okuno ◽  
Hideto Tanoue ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Nanoimprint Lithography ◽  
Room Temperature ◽  
Hole Transport ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Insulating Layer ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Ito Glass

ABSTRACTThe microfabrication technologiesfor organic light-emitting devices (OLEDs) are essential to the fabrication of the next generation of light-emitting devices. The micro-OLEDs fabricated by room-temperature curing nanoimprint lithography (RTC-NIL) using diamond molds have been investigated. However, light emissions from 10 μm-square-dot OLEDs fabricated by the RTC-NIL method have not been uniform. Therefore, we proposed the fabrication of micro-OLEDs by room-temperature curing nanocontact-print lithography (RTC-NCL) using the diamond-like carbon (DLC) mold. The DLC molds used in RTC-NCL were fabricated by an electron cyclotron resonance (ECR) oxygen ion shower with polysiloxane oxide mask in electron beam (EB) lithography technology. The mold patterns are square and rectangle dots which has 10 µm-width, 10 µm-width and50 µm-length, respectively. The height of the patterns is 500 nm. The DLC molds were used to form the insulating layer of polysiloxane in RTC-NCL. We carried out the RTC-NCL process using the DLC mold under the following optimum conditions: 0.1 MPa-pressure for coating DLC mold with polysiloxane film, 2.1 MPa-pressure for transferring polysiloxane from DLC mold pattern to indium tin oxide (ITO) glass substrate. We deposited N, N'-Diphenyl -N, N'-di (m-tolyl)benzidine (TPD) [40 nm-thickness] as hole transport layer / Tris(8-quinolinolato)aluminum (Alq3) [40 nm-thickness] as electron transport layer / Al [200 nm-thickness] as cathode on ITO glass substrateas anode in this order. We succeeded in formation of the insulating layer with square and rectangle dots which has 10 µm-width,10 µm-width and 50 µm-length, and operation of micro-OLEDs by RTC-NIL using DLC molds.

The Study of Hole Injection in OLEDs with Ultra-Thin Sol-Gel TiO2 Layer

2011 ◽  
Vol 189-193 ◽  
pp. 42-46
Author(s):  
You Wang Hu ◽  
Xiao Yan Sun ◽  
Jian Duan
Keyword(s):  
Sol Gel ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Transport Layer ◽  
Hole Injection ◽  
Hole Transport Layer ◽  
Carrier Injection ◽  
Light Emitting ◽  
Organic Light ◽  
Pre Treatment

Organic light-emitting diodes (OLEDs) with inserting an ultrathin sol–gel titanium oxide (TiO2) buffer layer between the ITO anode and hole transport layer (HTL) were fabricated. The carrier injection and the device efficiency were affected by surface morphology of TiO2, which was changed by different plasma pre-treatment of ITO. Treated by CF4 plasma, the TiO2 layer is the smoothest, and treated by H2 plasma it is like island. The TiO2 layer like island is favor of carrier injection from the anode, which was attributed to the point discharged.

Sign in / Sign up

Export Citation Format

Share Document