Substrate Polarity Effects on the Interface Electronic Structure in Organic Light Emitting Diodes

2016 ◽  
Vol 852 ◽  
pp. 746-749
Author(s):  
Huang Tian ◽  
Xin Zhao ◽  
Qiang Zhang ◽  
Huai Xin Wei
Keyword(s):  
Electronic Structure ◽  
Performance Enhancement ◽  
Open Circuit ◽  
Organic Electronic Devices ◽  
Light Emitting ◽  
Organic Layers ◽  
Interface Dipole ◽  
Potential Applications ◽  
The Difference ◽  
Polarity Effects

Organic layers deposited on various polarity substrates and the electronic structures of (PTCDA/TiOPc) on hydrophobic and hydrophilic substrates have been studied by ultraviolet photoemission spectroscopy. The difference between work function and polarity of the substrates induce the formation of an interface dipole with corresponding shift in the relative position of molecular levels across the interface. While the vacuum level and open circuit voltage show vastly difference respectively, the barrier between anode-organic or organic-cathode also changes from 0.75eV to 1.13eV or 0.35eV to 0.65eV. The results show the possibility of tuning the electronic structure by the modification of substrate and potential applications on performance enhancement in organic electronic devices.

Effects of Various Types of Doping on the Electronic Structure of Organic Interfaces

2005 ◽  
Vol 871 ◽  
Author(s):  
Kazuhiko Seki ◽  
Toshio Nishi ◽  
Senku Tanaka ◽  
Tadanobu Ikame ◽  
Hisao Ishii ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Electronic Devices ◽  
Quantitative Information ◽  
Atmospheric Gases ◽  
Organic Electronic Devices ◽  
Atmospheric Effect ◽  
Organic Layers ◽  
Organic Interfaces ◽  
Effect Transistor ◽  
Effect Of Oxygen

AbstractIn various organic electronic devices, interfaces formed by organic layers can play important roles. We have been studying various organic interfaces for clarifying their structure and electronic structure. In this talk, we will report our recent study of the effect of various types of doping for a variety of dopants – residual impurity, atmospheric gases, and metallic and organic intentional dopants. In particular, detailed and quantitative information about the effect of oxygen from the viewpoint of electronic structure was obtained for titanyl phthalocyanine (TiOPc), and the results corresponded well with the recent report of atmospheric effect on orga nic field effect transistor.

The Light Extraction Efficiency Enhancement in Organic Light-Emitting Diodes with Substrate Modifications

2012 ◽  
Vol 605-607 ◽  
pp. 2031-2034
Author(s):  
Chong Wang ◽  
Jun Wang ◽  
Kai Yuan ◽  
Lei Yu
Keyword(s):  
Light Emitting Diodes ◽  
Extraction Efficiency ◽  
Internal Quantum Efficiency ◽  
Organic Thin Films ◽  
Organic Light Emitting Diodes ◽  
Light Extraction Efficiency ◽  
Light Emitting ◽  
Organic Layers ◽  
Organic Light ◽  
The Difference

The internal quantum efficiency of organic light-emitting diodes (OLEDs) can reach values near to 100%. Due to the difference among the refractive indices of the substrate, anode, organic thin films, and the air, two wave-guiding phenomena arise in the anode/organic layers and substrate of the OLEDs. In this paper, the substrate modifications are developed to simulate the optical luminous field for OLEDs. Monte Carlo method was used to investigate enhancement of the external extraction efficiency, which is related to the total reflection inside the device by changing the structure of the substrate.

scholarly journals Influences of MgO(001) and TiO2(101) Supports on the Structures and Properties of Au Nanoclusters

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 16
Author(s):  
Jinhua Gao ◽  
Yuehong Ren ◽  
Qingzhen Han ◽  
Hao Wen ◽  
Zhaotan Jiang
Keyword(s):  
Electronic Structure ◽  
Catalytic Activity ◽  
Density Functional ◽  
Gold Nanoclusters ◽  
Reduction Reaction ◽  
Surface Charges ◽  
Photoelectric Properties ◽  
Structures And Properties ◽  
Potential Applications ◽  
The Difference

Due to the unique structures, photoelectric properties, good catalytic activity, and broad potential applications, gold nanoclusters (Au n ) received extensive attention in catalysis, bioengineering, environmental engineering, and so on. In the present work, the structures and properties of Au n adsorbed on the MgO(001) and TiO 2 (101) surfaces were investigated by density functional theory. The results showed that the catalytic properties of Au n will be enhanced when Au n is adsorbed on certain supports. Because the difference of the outer electronic structure of metals in supports, the direction of the charge transfer was different, thus inducing the different charge distribution on Au n . When Au n was adsorbed on MgO(001) [TiO 2 (101)] surface, Au n will have negative [positive] charges and thus higher catalytic activity in oxidation [reduction] reaction. The variation of surface charges caused by the support makes Au n possess different catalytic activity in different systems. Moreover, the electronic structure of the support will make an obvious influence on the s and d density of states of Au n , which should be the intrinsic reason that induces the variations of its structure and properties. These results should be an important theoretical reference for designing Au n as the photocatalyst applied to the different oxidation and reduction reactions.

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

scholarly journals Effect of Laser Irradiation on Emissivity of Flame-Generated Nanooxides

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2303
Author(s):  
Silvana De Iuliis ◽  
Roberto Dondè ◽  
Igor Altman
Keyword(s):  
Laser Irradiation ◽  
Light Emission ◽  
Energy Gap ◽  
Particle Temperature ◽  
Electron Excitation ◽  
Flame Spray ◽  
Energy Bands ◽  
Light Emitting ◽  
Spectral Behavior ◽  
The Difference

The application of pyrometry to retrieve particle temperature in particulate-generating flames strictly requires the knowledge of the spectral behavior of emissivity of light-emitting particles. Normally, this spectral behavior is considered time-independent. The current paper challenges this assumption and explains why the emissivity of oxide nanoparticles formed in flame can change with time. The suggested phenomenon is related to transitions of electrons between the valence and conduction energy bands in oxides that are wide-gap dielectrics. The emissivity change is particularly crucial for the interpretation of fast processes occurring during laser-induced experiments. In the present work, we compare the response of titania particles produced by a flame spray to the laser irradiation at two different excitation wavelengths. The difference in the temporal behavior of the corresponding light emission intensities is attributed to the different mechanisms of electron excitation during the laser pulse. Interband transitions that are possible only in the case of the laser photon energy exceeding the titania energy gap led to the increase of the electron density in the conduction band. Relaxation of those electrons back to the valence band is the origin of the observed emissivity drop after the UV laser irradiation.

scholarly journals Foldable and washable textile-based OLEDs with a multi-functional near-room-temperature encapsulation layer for smart e-textiles

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
So Yeong Jeong ◽  
Hye Rin Shim ◽  
Yunha Na ◽  
Ki Suk Kang ◽  
Yongmin Jeon ◽  
...  
Keyword(s):  
Room Temperature ◽  
Wearable Electronics ◽  
Ambient Conditions ◽  
Light Emitting ◽  
Stable Operating ◽  
Mechanical Durability ◽  
Potential Applications ◽  
Wearable Electronic ◽  
Data Signal ◽  
Wearable Electronic Devices

AbstractWearable electronic devices are being developed because of their wide potential applications and user convenience. Among them, wearable organic light emitting diodes (OLEDs) play an important role in visualizing the data signal processed in wearable electronics to humans. In this study, textile-based OLEDs were fabricated and their practical utility was demonstrated. The textile-based OLEDs exhibited a stable operating lifetime under ambient conditions, enough mechanical durability to endure the deformation by the movement of humans, and washability for maintaining its optoelectronic properties even in water condition such as rain, sweat, or washing. In this study, the main technology used to realize this textile-based OLED was multi-functional near-room-temperature encapsulation. The outstanding impermeability of TiO2 film deposited at near-room-temperature was demonstrated. The internal residual stress in the encapsulation layer was controlled, and the device was capped by highly cross-linked hydrophobic polymer film, providing a highly impermeable, mechanically flexible, and waterproof encapsulation.

scholarly journals A ΔSOC-based equalization strategy applied to industry

2020 ◽  
Author(s):  
Maonan Wang ◽  
Chun Chang ◽  
Feng Ji
Keyword(s):  
Open Circuit ◽  
Battery Pack ◽  
Battery Management System ◽  
Battery Management ◽  
Battery Cell ◽  
New Strategy ◽  
The Difference ◽  
Relative Errors ◽  
The Relationship ◽  
Battery Cells

Abstract The voltage-based equalization strategy is widely used in the industry because the voltage (U) of the battery cell is very easy to obtain, but it is difficult to provide an accurate parameter for the battery management system (BMS). This study proposes a new equalization strategy, which is based on the difference between the state of charge (SOC) of any two battery cells in the battery pack, that is, a ΔSOC-based equalization strategy. The new strategy is not only as simple as the voltage-based equalization strategy, but it can also provide an accurate parameter for the BMS. Simply put, using the relationship between the open circuit voltage and the SOC of the battery pack, the proposed strategy can convert the difference between the voltage of the battery cells into ΔSOC, which renders a good performance. Additionally, the required parameters are all from the BMS, and no additional calculation is required, which makes the strategy as simple as the voltage-based balancing strategy. The four experiments show that the relative errors of ΔSOC estimated by the ΔSOC-based equalization strategy are 0.37%, 0.39%, 0.1% and 0.17%, and thereby demonstrate that the ΔSOC-based equalization strategy proposed in this study shows promise in replacing the voltage-based equalization strategy within the industry to obtain better performance.

scholarly journals Waiting for Act 2: what lies beyond organic light-emitting diode (OLED) displays for organic electronics?

Nanophotonics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 31-40
Author(s):  
Stephen R. Forrest
Keyword(s):  
Organic Electronics ◽  
Light Emitting Diode ◽  
Electronic Devices ◽  
Organic Electronic Devices ◽  
Organic Electronic ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Semiconductor Thin Films ◽  
Display Technology

AbstractOrganic light-emitting diode (OLED) displays are now poised to be the dominant mobile display technology and are at the heart of the most attractive televisions and electronic tablets on the market today. But this begs the question: what is the next big opportunity that will be addressed by organic electronics? We attempt to answer this question based on the unique attributes of organic electronic devices: their efficient optical absorption and emission properties, their ability to be deposited on ultrathin foldable, moldable and bendable substrates, the diversity of function due to the limitless palette of organic materials and the low environmental impact of the materials and their means of fabrication. With these unique qualities, organic electronics presents opportunities that range from lighting to solar cells to medical sensing. In this paper, we consider the transformative changes to electronic and photonic technologies that might yet be realized using these unconventional, soft semiconductor thin films.

Charge-Transfer Dipoles at the Si-SiO2 Interface and the Metal-Semiconductor Worfunction Difference In Mos Devices.

1987 ◽  
Vol 105 ◽  
Author(s):  
Hisham Z. Massoud
Keyword(s):  
Dipole Moment ◽  
Charge Transfer ◽  
Dipole Moments ◽  
Silicon Substrates ◽  
Interface Dipole ◽  
Mos Devices ◽  
Flatband Voltage ◽  
The Difference ◽  
Definition Of ◽  
Mos Structures

AbstractThe magnitude of the dipole moment at the Si-SiO2 interface resulting from partial charge transfer that takes place upon the formation of interface bonds has been calculated. The charge transfer occurs because of the difference in electronegativity between silicon atoms and SiO2 molecules which are present across the interface. Results obtained for (100) and (111) silicon substrates indicate that the magnitude of the interface dipole moment is dependent on substrate orientation and the interface chemistry. Dipole moments at the Si-SiO2 and gate-SiO2 interfaces should be included in the definition of the flatband voltage VFB of MOS structures. CV-based measurements of the metal-semiconductor workfunction difference φms on (100) and (111) silicon oxidized in dry oxygen and metallized with Al agree with the predictions of this model. Other types of interface dipoles and their processing dependence are briefly discussed.

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