scholarly journals Comparison of different organic solvents used in the luminescent material for OLED devices

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Emerson Roberto Santos ◽  
Eric Tsuneki Yoshiura Ono ◽  
Roberto Koji Onmori ◽  
Wang Shu Hui
Keyword(s):  
Organic Solvents ◽  
Indium Tin Oxide ◽  
Light Emitting Diode ◽  
Electrical Current ◽  
Hole Transport ◽  
Polymer Chains ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Hole Transport Layer ◽  
Luminescent Material

In this work, organic light-emitting diode (OLED) devices were mounted using the structure: glass (as substrate)/indium tin oxide (ITO) (as anode)/poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) (as hole transport layer)/poly[9,9-dioctifluorene-alt-bis-tienilene(benzotiadiazole)] (PFTB) (as luminescent material)/aluminum-doped zinc oxide (AZO) (as electron transport layer)/aluminum (as cathode). The PFTB was synthetized at laboratory and diluted in different organic solvents as chloroform and trichlorobenzene. The I-V curves of OLED devices showed that the trichlorobenzene used to dillute the PFTB improved the performance for OLED devices promoting the highest electrical current of ≈50 mA and the lowest range of thresold voltage from ≈2.5 to 5 volts, while the device OLEDs mounted with PFTB dilutted in chloroform presented maximum electrical current of ≈23 mA and range of thresold voltage from ≈5 to 8 volts. A hypothesis that explain these results can be attributed to the boiling point of the organic solvent of trichlorobenzene (≈214.4ºC) to be higher than the one of the chloroform (≈61.1ºC), favoring better rearrangement of the polymer chains of PFTB and interfaces between thin films PFTB/PEDOT:PSS and PFTB/AZO improving the injection of charges (holes and electrons) inside the OLEDs devices.

Singlet Exciton Quenching by Radical Cations of Aromatic Diamines as an Electron Donor in Organic Electroluminescent Devices

2011 ◽  
Vol 1286 ◽  
Author(s):  
Munkhbat Battulga ◽  
Gendensuren Bolormaa ◽  
Batjargal Naranbileg ◽  
Chimed Ganzorig
Keyword(s):  
Indium Tin Oxide ◽  
Radical Cations ◽  
Chemical Oxidation ◽  
Hole Transport ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Hole Transport Layer ◽  
Aromatic Diamines ◽  
Visible Absorption ◽  
Organic Electroluminescent

ABSTRACTIn this study, we report the luminescence quenching by radical cations of aromatic diamines used as a hole transport layer (HTL) in organic electroluminescent (EL) devices. The EL characteristics of green organic EL devices with an electron transport layer (ETL) as an emitter i.e. ITO/TPD HTL/Alq3ETL/Al is studied. Here, ITO, TPD, and Alq3are abbreviations for indium-tin-oxide, N,N’-diphenyl-N,N’-bis(3-methylphenyl)-1,1’-biphenyl-4,4’-diamine, and tris (8-hydroxyquinoline) aluminum, respectively. UV-visible absorption and electrochemical data indicate the formation of radical cations in thin film and solution of TPD after chemical oxidation. We find that the EL luminance increases less than linearly with an increase in current for the EL devices studied in this study. The luminance loss in the devices is attributed to quenching of singlet excited states by large excess radical cations of TPD are accumulated in the emission zone due to large overlap between a flourescence spectrum of Alq3and an absorption spectrum of radical cations of TPD.

scholarly journals Improvement of Vacuum Free Hybrid Photovoltaic Performance Based on a Well-Aligned ZnO Nanorod and WO3 as a Carrier Transport Layer

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1490
Author(s):  
Nguyen Tam Nguyen Truong ◽  
Hai Ha Thi Hoang ◽  
Chinho Park
Keyword(s):  
Indium Tin Oxide ◽  
Carrier Transport ◽  
Photovoltaic Performance ◽  
Hole Transport ◽  
Transport Layer ◽  
Zinc Oxide Nanorods ◽  
Electron Transport Layer ◽  
Hole Transport Layer ◽  
Device Performance ◽  
Oxide Nanorods

Well-aligned zinc oxide nanorods (WA-ZnO Nrods) with different lengths were synthesized and the effects of the growth times on the optical, morphological, and electrical properties of the WA-ZnO Nrods were examined. We also investigated the application of WA-ZnO Nrods as an electron transport layer (ETL) and tungsten trioxide (WO3) as a hole transport layer (HTL) to vacuum free hybrid photovoltaic (HPV) performance. The eutectic gallium–indium (EGaIn) alloy was used as a top electrode coated using a brush-painting method. A device with the structure of indium tin oxide (ITO)/WA-ZnO Nrods/(P3HT:PCBM)/WO3/EGaIn was optimized and fabricated. The maximum power conversion efficiency (PCE) was ~4.5%. Improvement of the device performance indicates that the well-aligned ZnO Nrods and WO3 can effectively be applied as charge carrier transport layer for vacuum free hybrid (HPV).

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 Solid-State Solar Cells Based on TiO2 Nanowires and CH3NH3PbI3 Perovskite

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 404
Author(s):  
Abdul Sami ◽  
Arsalan Ansari ◽  
Muhammad Dawood Idrees ◽  
Muhammad Musharraf Alam ◽  
Junaid Imtiaz
Keyword(s):  
Solar Cells ◽  
Solid State ◽  
Light Trapping ◽  
Active Material ◽  
Perovskite Solar Cells ◽  
Hole Transport ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Hole Transport Layer ◽  
Tio2 Nanowires

Perovskite inorganic-organic solar cells are fabricated as a sandwich structure of mesostructured TiO2 as electron transport layer (ETL), CH3NH3PbI3 as active material layer (AML), and Spiro-OMeTAD as hole transport layer (HTL). The crystallinity, structural morphology, and thickness of TiO2 layer play a crucial role to improve the overall device performance. The randomly distributed one dimensional (1D) TiO2 nanowires (TNWs) provide excellent light trapping with open voids for active filling of visible light absorber compared to bulk TiO2. Solid-state photovoltaic devices based on randomly distributed TNWs and CH3NH3PbI3 are fabricated with high open circuit voltage Voc of 0.91 V, with conversion efficiency (CE) of 7.4%. Mott-Schottky analysis leads to very high built-in potential (Vbi) ranging from 0.89 to 0.96 V which indicate that there is no depletion layer voltage modulation in the perovskite solar cells fabricated with TNWs of different lengths. Moreover, finite-difference time-domain (FDTD) analysis revealed larger fraction of photo-generated charges due to light trapping and distribution due to field convergence via guided modes, and improved light trapping capability at the interface of TNWs/CH3NH3PbI3 compared to bulk TiO2.

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.

Simulation and Optimization of C60-Based Organic Light-Emitting Diodes

2021 ◽  
Vol 1026 ◽  
pp. 142-146
Author(s):  
Shuo Wang
Keyword(s):  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Hole Transport ◽  
Organic Light Emitting Diodes ◽  
Transport Layer ◽  
Hole Transport Layer ◽  
Optical Parameters ◽  
Light Emitting ◽  
Simulation And Optimization ◽  
Organic Light

In this work we present a detailed analysis of the current-voltage variance from tris(8-hydroxyquinoline)aluminum (Alq3) based organic light emitting diodes using general-purpose photovoltaic device model (GPVDM) software as a function of: the choice of C60, the thickness of emission layer and hole-transport layer. The electrical and optical parameters of all layers were extracted from the material directory available in GPVDM. The calculations fully consider dispersion in glass substrate, indium tin oxide anode, the organic layers as well as the dispersion in the metal cathode. As expected, applied voltage was strongly dependent on the thickness of the function layer inside the devices. Finally, guidelines for designing devices with optimum turn-on voltage and thickness are presented.

Enhanced Performance Organic Light Emitting Diode With CuI:CuPC Composite Hole Transport Layer

2020 ◽  
Vol 19 ◽  
pp. 699-703
Author(s):  
Vinay Mohan ◽  
A. K. Gautam ◽  
S. D. Choudhary ◽  
M. K. Mariam Bee ◽  
R. Puviarasi ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Transport Layer ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light

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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