scholarly journals Investigation of the dynamic parameters of electroluminescence in different parts of the spectrum in local regions of the light-emitting heterostructure

2021 ◽  
Vol 2086 (1) ◽  
pp. 012083
Author(s):  
I V Frolov ◽  
O A Radaev ◽  
V A Sergeev
Keyword(s):  
Energy Level ◽  
Short Wavelength ◽  
Energy Levels ◽  
Charge Carriers ◽  
Electroluminescence Spectrum ◽  
Dynamic Parameters ◽  
Light Emitting ◽  
Long Wavelength ◽  
Different Parts

Abstract A method for measuring the distribution of the differential charge carriers lifetime over energy levels in the local regions of a light-emitting heterostructure is presented. The method has been tested on commercial green InGaN-based LEDs. It has been determined that with an increase in the energy level (with decreasing wavelength), the charge carriers lifetime decreases. It is shown that the relative inhomogeneity of the distribution of the charge carriers lifetimes in local regions of the die in the long-wavelength part of the electroluminescence spectrum is higher than in the short-wavelength part of the spectrum.

A stepwise energy level doping structure for improving the lifetime of phosphorescent organic light-emitting diodes

2017 ◽  
Vol 5 (16) ◽  
pp. 3948-3954 ◽  
Author(s):  
Wook Song ◽  
Taekyung Kim ◽  
Yoonkyoo Lee ◽  
Jun Yeob Lee
Keyword(s):  
Energy Level ◽  
Light Emitting Diodes ◽  
Energy Levels ◽  
Organic Light Emitting Diodes ◽  
Host Material ◽  
Light Emitting ◽  
Organic Light

A stepwise energy level doping structure for improving the lifetime of organic light-emitting diodes was developed by doping two emitters with different energy levels in the same host material as separated emitting layers.

scholarly journals Application of quinoline derivatives in third-generation photovoltaics

2021 ◽  
Author(s):  
Gabriela Lewinska ◽  
Jerzy Sanetra ◽  
Konstanty W. Marszalek
Keyword(s):  
Solar Cells ◽  
Polymer Solar Cells ◽  
Energy Levels ◽  
Photovoltaic Cells ◽  
Third Generation ◽  
Quinoline Derivatives ◽  
Emission Layer ◽  
Light Emitting ◽  
Photovoltaic Applications ◽  
Architecture And Design

AbstractAmong many chemical compounds synthesized for third-generation photovoltaic applications, quinoline derivatives have recently gained popularity. This work reviews the latest developments in the quinoline derivatives (metal complexes) for applications in the photovoltaic cells. Their properties for photovoltaic applications are detailed: absorption spectra, energy levels, and other achievements presented by the authors. We have also outlined various methods for testing the compounds for application. Finally, we present the implementation of quinoline derivatives in photovoltaic cells. Their architecture and design are described, and also, the performance for polymer solar cells and dye-synthesized solar cells was highlighted. We have described their performance and characteristics. We have also pointed out other, non-photovoltaic applications for quinoline derivatives. It has been demonstrated and described that quinoline derivatives are good materials for the emission layer of organic light-emitting diodes (OLEDs) and are also used in transistors. The compounds are also being considered as materials for biomedical applications.

scholarly journals Demonstration of epitaxial growth of strain-relaxed GaN films on graphene/SiC substrates for long wavelength light-emitting diodes

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Ye Yu ◽  
Tao Wang ◽  
Xiufang Chen ◽  
Lidong Zhang ◽  
Yang Wang ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Light Emitting Diodes ◽  
Nitrogen Plasma ◽  
Biaxial Stress ◽  
Organic Chemical ◽  
Graphene Surface ◽  
Light Emitting ◽  
Long Wavelength ◽  
Pre Treatment ◽  
Wavelength Light

AbstractStrain modulation is crucial for heteroepitaxy such as GaN on foreign substrates. Here, the epitaxy of strain-relaxed GaN films on graphene/SiC substrates by metal-organic chemical vapor deposition is demonstrated. Graphene was directly prepared on SiC substrates by thermal decomposition. Its pre-treatment with nitrogen-plasma can introduce C–N dangling bonds, which provides nucleation sites for subsequent epitaxial growth. The scanning transmission electron microscopy measurements confirm that part of graphene surface was etched by nitrogen-plasma. We study the growth behavior on different areas of graphene surface after pre-treatment, and propose a growth model to explain the epitaxial growth mechanism of GaN films on graphene. Significantly, graphene is found to be effective to reduce the biaxial stress in GaN films and the strain relaxation improves indium-atom incorporation in InGaN/GaN multiple quantum wells (MQWs) active region, which results in the obvious red-shift of light-emitting wavelength of InGaN/GaN MQWs. This work opens up a new way for the fabrication of GaN-based long wavelength light-emitting diodes.

Radical induced intermolecular linkage and energy level modifications of a porphyrin monolayer

2017 ◽  
Vol 53 (6) ◽  
pp. 1104-1107 ◽  
Author(s):  
Abdolreza Jahanbekam ◽  
Colin Harthcock ◽  
David Y. Lee
Keyword(s):  
Energy Level ◽  
Scanning Tunneling Microscopy ◽  
Surface Structure ◽  
Energy Levels ◽  
New Method ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Molecular Scale

A new method to directly modify the surface structure and energy levels of a porphyrin monolayer was examined with molecular-scale resolution using scanning tunneling microscopy and spectroscopy (STM and STS) and presented in this communication.

VIBRATIONAL ENERGIES OF MEMBERS IN STRUCTURAL NETWORKS FITTED WITH TUNED VIBRATION ABSORBERS

2006 ◽  
Vol 06 (02) ◽  
pp. 269-284 ◽  
Author(s):  
SUNNY K. GEORGE ◽  
K. SHANKAR
Keyword(s):  
Energy Level ◽  
Vibrational Energy ◽  
General Structure ◽  
Energy Levels ◽  
Complex Structure ◽  
Input Power ◽  
Vibration Absorbers ◽  
Tuned Vibration Absorbers ◽  
Vibrational Energies ◽  
Structural Networks

The distribution of vibrational energy in members of a complex structure with tuned absorbers attached at the joints and subjected to dynamic loading is studied. The concept of power flows through the structure is used to determine the time-averaged energy levels of each member in the structure. The power flows are calculated using the time-averaged product of force and velocity at the input and coupling points (joints) of a general structure made of axially vibrating rods. The receptance approach is used to calculate the coupling forces and velocities in the structure. By balancing the input power against the dissipated powers, the time-averaged energy levels in members are determined. The main criteria studied here is the reduction in the frequency-averaged vibrational energy level of a member when an absorber is attached, expressed as a percentage compared to the case where there are no absorbers. The concept is first illustrated with a simple model of 2 axially vibrating rods with an absorber attached to the joint. Next, a more complex structure comprising 8 rods with arbitrary orientations and several absorbers attached to junctions is studied. The effect of activating absorbers at various locations on reducing the energy levels of certain members is examined. It is possible to estimate the usefulness of the absorber with respect to any member by determining the percentage reduction of energy level for that member.

Porphyrin doping of dichloride-bis(5,7-dichloroquinolin-8-olato)tin(IV) complex for electroluminescence

2013 ◽  
Vol 17 (05) ◽  
pp. 351-358 ◽  
Author(s):  
Mohammad Janghouri ◽  
Ezeddin Mohajerani ◽  
Mostafa M. Amini ◽  
Naser Safari
Keyword(s):  
Molecular Orbital ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Energy Levels ◽  
Orbital Energy ◽  
Homogeneous Layer ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Fundamental Structure ◽  
Organic Light

A method for obtaining red emission from an organic-light emitting diode has been developed by dissolving red and yellow dyes in a common solvent and thermally evaporating the mixture in a single furnace. Dichlorido-bis(5,7-dichloroquinolin-8-olato)tin(IV) complex ( Q2SnCl2 , Q = 5,7-dichloro-8-hydroxyquinoline) has been synthesized for using as a fluorescent material in organic light-emitting diodes (OLEDs). The electronic states HOMO (Highest Occupied Molecular Orbital)/LUMO (Lowest Occupied Molecular Orbital) energy levels explored by means of cyclic voltammetry measurements. A device with fundamental structure of ITO/PEDOT:PSS (55nm)/PVK (90nm)/ Q2SnCl2/Al (180nm) was fabricated and its electroluminescence performance at various thicknesses of light emitting layer (LEL) of Q2SnCl2 is reported. By following this step, an optimal thickness for the doping effect was also identified and explained. Finally a device with fundamental structure of ITO/PEDOT:PSS (55nm)/PVK (90nm)/meso-tetraphenylporphyrin (TPP): Q2SnCl2 (75nm)/ Al (180nm) was fabricated and its electroluminescence performance at various concentrations of dye has been investigated. It is shown that this new method is promising candidate for fabrication of low cost OLEDs at more homogeneous layer.

PREPARATION AND CHARACTERIZATION OF Zr-DOPED TiN NANOFILM

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3455-3458
Author(s):  
ANPING LIU ◽  
YINFENG WANG ◽  
XUEHENG YANG
Keyword(s):  
Thin Film ◽  
Corrosion Resistance ◽  
Energy Level ◽  
Mixed Crystal ◽  
Energy Levels ◽  
Energy Band Structure ◽  
Reactive Magnetron ◽  
Tin Coating ◽  
New Energy

The Zr -doped TiN coating, a nanometer (Ti, Zr)N thin film, has been deposited by reactive magnetron sputtering on slides and Al substrates. The crystalline phase and energy band structure have been analyzed by XRD and STS. The results of XRD show that the (Ti, Zr)N film is poly crystalline and consisted of mixed crystal of TiN and ZrN phase. The STS spectra show that Zr -doping didn't change the position and band-gap of energy level, only two new energy levels appeared, Eg = 0.33eV and Eg = 0.42eV. According to the results of measurement, (Ti, Zr)N has higher hardness and better corrosion resistance than TiN by Zr -doping.

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