bluuebunny/crossref_metadata_2025_split huggingface dataset:
Loss Process in Efficiency of Blue Organic Electroluminescent Devices
Authors: Enatsu Yasuo , Ganzorig Chimed , Fujihira Masamichi 
Published: June 2019

AbstractWe report EL characteristics of blue organic electroluminescent (EL) devices with a hole transport layer (HTL) as an emitter i.e. ITO/NPD/BCP/Alq3/Cs(0.5 nm)/Al. Here, ITO, NPD, BCP, and Alq3 are abbreviations for indium-tin-oxide, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]- biphenyl, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, and tris(8-hydroxyquinoline) aluminum, respectively. Three different chemically modified ITO electrodes were used. As a hole-injecting buffer layer, copper phthalocyanine (CuPc) or 4,4',4''-tris-(3-methylphenylphenylamino) triphenylamine (MTDATA) was used in this study. We found that the luminance increased less than linearly with an increase in current for all EL devices studied even when hole and electron injection were enhanced. The luminance loss in the device is attributed to quenching singlet excited states (1NPD*) by large excess radical cations (NPD+.) accumulated in the emission zone due to large overlap between a fluorescence spectrum of 1NPD* and an absorption spectrum of NPD+.. In addition, 1NPD* can be also quenched by radical anions (NPD-.) when excess electrons are injected.
In-situDevelopment and Study of Conducting Polymer Electrodes on PVDF Substrates for Electro-Acoustic Application in Cochlear Implants
Authors: Dwivedi Arpit , Roseman Rodney 
Published: June 2019

AbstractSensorineural hearing loss (profound deafness) is a result of the inability of the transductory structures in the cochlea (organ of Corti) to convert the mechanical displacement of the basilar membrane to neural signals. A class of devices known as Cochlear Implants can significantly enhance the hearing ability in these patients. Fundamentally different from the existing cochlear implant technology, are the totally implantable piezoelectric based devices that are being developed. The unit is completely self-contained, designed to work without any signal amplifiers or transmission elements, greatly simplifying the stimulation process, and enhancing the cosmetic appearance of the patient. These devices utilize the bending piezoelectric effect. Device design consists of arrays of elements of piezoelectric polymer films with conducting polymer electrodes embedded in a flexible substrate with the whole device coated with an insulating layer. The incoming mechanical energy (pressure waves) into the cochlea generates electrical charge by virtue of the piezoelectric effect of the film. The generated charge is fed to electrical connections evaporated on the substrate and is used to stimulate surviving nerve fibers in the cochlea. In certain environments where acoustic impedance matching is limited by size constraints and conducting liquid medium, the advantage of polymer based devices over ceramics and metal based devices, are their flexibility, low acoustic impedance, and high sensitivity. However, in order to utilize these useful properties, the electrode material is an important issue, since the conventionally used metal electrodes, have high acoustic impedance and also impose mechanical clamping on the soft polymer which can significantly reduce the electromechanical efficiency of the transducer. Due to its flexibility, strong coherent interfaces, and significantly improved acoustic transparency, such an all-polymer electroactive system is compared to a metal-polymer system of similar design and also compared to the current technology.
Nanocrystalline semiconductor LEDs with simple structure and high efficiency
Authors: Bertram Dietrich , Weiler Volker , Talapin Dimitri , Weller Horst 
Published: June 2019

AbstractNanocrystalline semiconductor particles exhibit a size dependent bandgap emission, due to size quantisation effects. These particles are derived from solution chemistry and can be made monodisperse under the right synthesis conditions. Compared to organic materials, the inorganic nanoparticles show much higher stability against oxidation and degradation, which makes them an interesting candidate for LEDs and displays. So far, LEDs based on semiconductor nanoparticles typically included low stability organic materials to provide charge injection. The talk will present a new class of nanoparticle LEDs, made without sensitive organic materials. These LEDs show high efficiencies, well defined color throughout the red to green part of the visible spectrum and improved stability under ambient conditions without excessive encapsulation. Using high quality monodisperse suspensions, high color purity is achieved for the emission which paves the road to cheap, high quality displays based on inorganic semiconductor nanoparticles.
Investigation of the electronic properties of cyclopentadithiophene polymers and copolymers
Authors: Coppo Paolo , Turner Michael L. , Cupertino Domenico C. , Yeates Stephen G. 
Published: June 2019

AbstractCyclopentadithiophene based homopolymers and copolymers have been investigated as semiconductor layers in field effect transistors. They generally show low hole mobilities due to a disordered amorphous structure in the solid state. FET mobility can be enhanced in the homopolymer, although this results in poor on/off ratio of the device. The low mobilities may be attributed to the presence of solubilizing alkyl chains normal to the long axis of the polymer which prevent the self assembly of the polymer into an ordered π-stacked configuration.
The Effects of Structural Disorder on the Luminescence Quenching in Poly(phenylene vinylene)
Authors: Moses Daniel , Schmechel Roland , Heeger Alan J. 
Published: June 2019

AbstractLuminescence quenching experiments on oriented and drop-cast poly(phenylene vinylene), (PPV), films identify the excitons in these polymer films as Wannier-Mott excitons. The data are interpreted in terms of a distribution of exciton binding energies (Eb). We find that the width of this distribution is well correlated with the degree of structural disorder. The relatively small mean EbEb, approximately 60 meV, results in field-induced exciton disociation that limits the quantum efficiency obtained from polymer-based light emitting diodes (PLEDs) which typically are operated at applied fields of 106 V/cm or greater where the field-induced exciton disociation is significant. We present data and analysis that support these conclusions, as well as a discussion on the implications of our findings on polymer-based display technology.
Source / drain contacts in organic polymer thin film transistors
Authors: Martin Sandrine , Hamilton Michael C. , Kanicki Jerzy 
Published: June 2019

AbstractOrganic polymer based thin-film transistors (OP-TFTs) look very promising for flexible organic electronics. In this paper, we describe devices based on a gate-planarized structure and using spin-coated organic polymer. We have analyzed the role of the device source and drain contacts and we present data indicating Schottky behavior of the contacts in OP-TFTs. In addition, we describe a quantitative evaluation of the source drain series resistances and extract the OP-TFT intrinsic electrical parameters.
The Crystal Sructure of Anthracene up to 22 GPa: a X-ray Diffraction Study
Authors: Oehzelt Martin , Heimel Georg , Resel Roland , Puschnig Peter , Hummer Kerstin , Ambrosch-Draxl Claudia , Takemura Kenichi , Nakayama Atsuko 
Published: June 2019

AbstractThe aim of this study is to investigate the crystalline structure of anthracene C14H10 under high pressure performing angle dispersive x-ray diffraction experiments using synchrotron radiation in combination with Rietveld refinements and rigid body approximation. High hydrostatic pressure was applied up to 27.8 GPa using a diamond anvil cell. Full structural information (molecular orientations and lattice constants) is given up to a pressure of 20.3 GPa. At the highest pressure of 22.7 GPa the unit cell volume is decreased by 36.8%. Fourier transformation of the diffracted intensities reveals the electron density distribution within the unit cell. A pressure induced increase of the electron densities between adjacent molecules is observed. These findings are shown to be in agreement with theoretical calculations and hint towards the evolution of the anisotropic conductivity with pressure.
Sol-gel Nanohybrid Materials Incorporating Functional Thiacalixarenes for Non-Linear Optical Applications
Authors: Desroches C. , Parola S. , Cornu D. , Miele P. , Baldeck P. L. , Lopes C. 
Published: June 2019

AbstractMacrocyclic thiacalixarenes have interesting non-linear optical properties. Thiacalixarenes bearing phenylazo, imino, ethynylic groups or platinum derived acetylides on the upper rims were designed, prepared and fully characterised. They showed interesting properties for optical limiting. Moreover these macrocycles are highly soluble in organic solvents and can easily be embedded in inorganic matrix using the sol-gel routes.Thiacalixarene based class I and II solid-state materials were prepared and their optical limiting behaviour was investigated.
Pulsed Laser Deposition of Aluminum Tris-8-hydroxyquinline and TPD Thin Films
Authors: Ebihara Kenji , Shin Pail-Kyun , Ohshima Tamiko , Kurihara Hiroshi , Ikegami Tomoaki , Yamaguchi Toshihisa , Sakai Takamasa 
Published: June 2019

AbstractThin films of low molecular weight electroluminescence (EL) materials, Alq3 (aluminum tirs-8-hydoroxyquinline), TPD (N,N'-diphenyl-N,N'-bis (3methylphenyl)-(1,1'-biphenyle)-4, 4'-diamine) were deposited by pulsed laser ablation (PLA) method using KrF excimer laser and Nd:YAG laser. Optical absorption property, surface morphology and photoluminescence of the films were investigated. Alq3 films by Nd:YAG laser show slight absorption at around 400 nm, and TPD films by either KrF laser or Nd:YAG laser showed absorption at 320 nm and 360 nm. It was found that TPD thin films for EL devices can be deposited by PLAmethod usig Nd:YAG laser.
Photochemical Patterning Approaches for Multicolor Polymer Light Emitting Devices
Authors: Pogantsch A. , Trattnig G. , Rentenberger S. , Langer G. , Keplinger J. , Tillmann H. , Hörhold H.-H. , Scherf U. , Kern W. , Zojer E. 
Published: June 2019

AbstractThe patterning of conjugated polymers for multicolored electroluminescence applications is a current topic of research in polymer device technology. Several techniques including direct writing approaches such as ink-jet printing have been proposed to solve this challenge. We present an approach to tuning the (electro)luminescence color of a film consisting of a blend of conjugated polymers after its deposition by means of UV-irradiation in the presence of an active agent. This promises to be an alternative, highly parallel approach towards multicolored electroluminescence.
Insulating Biomaterials Research for Implantable Microelectronic Devices
Authors: Edell David J. 
Published: June 2019

AbstractDevelopments in the field of BioMEMS share many of the same issues encountered in the development of neural interface technology that has been underway for many decades. In addition to issues of function, other issues such as biocompatibility and bioresistance have also presented great challenges. The focus of this paper is on the development and testing of electrically insulating biomaterials for micro-devices that can be implanted in biological systems. A variety of accelerated degradation and accelerated detection of degradation techniques have been developed and are used to screen candidate materials. Direct tests of mechanical properties, adhesion, and chemical resistance are used for further assessment. Promising materials indicate what chemistry might be suitable for development of a Chemical Vapor Deposited (CVD) thin film coating. CVD coatings are under development that may be useful for insulation of very small, micromachined elements of an implantable device while only increasing the size of the device by a few micrometers. Materials passing in-vitro testing are then considered for in-vivo testing. Novel instrumentation for testing devices in-vivo has been developed.
Single Cell Based Microelectrode Array Biosensors
Authors: Yang Mo , Prasad Shalini , Zhang Xuan , Ozkan Mihrimah , Ozkan Cengiz S. 
Published: June 2019

AbstractExtracellular potential is an important parameter which indicates the electrical activity of live cells. Membrane excitability in osteoblasts plays a key role in modulating the electrical activity in the presence of chemical agents. The complexity of cell signal makes interpretation of the cellular response to a chemical agent very difficult. By analyzing shifts in the signal power spectrum, it is possible to determine a frequency spectrum also known as Signature Pattern Vectors (SPV) specific to a chemical. It is also essential to characterize single cell sensitivity and response time for specific chemical agents for developing detect-to-warn biosensors. We used a 4x4 multiple Pt microelectrode array to spatially position single osteoblast cells, by using a gradient AC field. Fast Fourier Transformation (FFT) and Wavelet Transformation (WT) analyses were used to extract information pertaining to the frequency of firing from the extracellular potential.
Fabrication and Simulation of Amorphous Carbon Cantilever Structures
Authors: Chua Daniel H.C. , Milne W.I. , Yu L.J. , Sheeja D. , Tay B.K. 
Published: June 2019

AbstractIn view of the superior bio-compatibility of amorphous carbon (a-C) films, a study has been carried out on the fabrication and simulation of free-standing amorphous carbon microcantilevers. The fabrication of micro-structure was carried out by a single photolithography step. A 1.7micro-meter thick, low stress, smooth (Rrms ∼0.75nm) a-C films were deposited by filtered cathodic vacuum arc deposition (FCVA) system, in conjunction with high substrate pulse biasing on patterned n-doped Si >100< substrates. Subsequently, the photoresist was lifted-off in acetone and which is followed by undercutting of the cantilever structures in 40% KOH solution. The deflection of the free-standing cantilever structures was measured using an optical profiler, and the stress in the a-C cantilever structures was independently calculated from the deflection of the cantilever beam and the total tilt angle. This stress value is compared with the stress in the film measured from the film-substrate sandwich by radius of curvature technique. Simulation of the cantilever assembly was carried out to obtain the deflection and stress distribution. The simulated parameters are compared with the experimental results.
Multi-Site, Neurotransmitter-Based Retinal Interface
Authors: Peterman Mark C. , Fishman Harvey A. 
Published: June 2019

AbstractNearly all retinal prosthetics have focused on electrical stimulation of the nervous system. We are developing a novel prosthetic interface for the retina based on neurotransmitter delivery. In the past, we have demonstrated the ability to stimulate individual rat pheochromacytoma cells (PC12 cell line) using microfluidic delivery through micron-sized apertures. This delivery was highly reproducible, very controllable, and quantifiable. But this early stage device was limited to a single stimulation site and crude microfluidics. Here, we present the next stage in microfluidic retinal prosthetics with a multi-stimulation site device that incorporates more advanced control over the microfluidic delivery. We created an array of apertures in a thin silicon nitride membrane, to which we can deliver neurotransmitters in an addressable manner. Excitable cells (PC12) are seeded on the device and imaged using Ca2+-sensitive dyes with a confocal microscope. We can then excite the cells at an array of multiple precise locations near the apertures, demonstrating the next step in neurotransmitter-based retinal prosthetics.
Functionalization of carbon nanotubes for self assembly applications
Authors: Ravindran Sathyajith , Chaudhary Sumit , Ozkan Mihrimah , Ozkan Cengiz S. 
Published: June 2019

AbstractWe report the controlled synthesis of multi-walled Carbon Nanotube-Quantum Dot (CNT-QD) heterojunctions using the Ethylene Carbodiimide Coupling procedure (EDC). Thiol stabilized ZnS capped CdSe quantum dots containing amine terminal groups (QDNH2) were conjugated with acid treated Multi-Walled Carbon Nanotubes (MWCNT) ranging from 400 nm to 4νm in length. SEM, TEM and FTIR were used to characterize the conjugation process.
A microfluidic device with integrated impedance detection for λ-DNA
Authors: Park Myung-Il , Hong Jonging , Yoon Dae Sung , Park Chong-Ook , Im Geunbae 
Published: June 2019

AbstractThe large optical detection systems that are typically utilized at present may not be able to reach their full potential as portable analysis tools. Accurate, early, and fast diagnosis for many diseases requires the direct detection of biomolecules such as DNA, proteins, and cells. In this research, a glass microchip with integrated microelectrodes has been fabricated, and the performance of electrochemical impedance detection was investigated for the biomolecules. We have used label-free λ-DNA as a sample biomolecule. By changing the distance between microelectrodes, the significant difference between DW and the TE buffer solution is obtained from the impedance-frequency measurements. In addition, the comparison for the impedance magnitude of DW, the TE buffer, and λ-DNA at the same distance was analyzed.
Biosensing in microfluidic channels using Fluorescence Polarization
Authors: Yadavalli Vamsi K. , Pishko Michael V. 
Published: June 2019

AbstractMicrofabricated microfluidic devices provide useful platforms for sensing and conducting immunoassays for high throughput screening and drug discovery. Here, Fluorescence Polarization has been used as a technique for probing binding events within 500 micron and smaller microfluidic channels fabricated in poly (dimethyl siloxane) (PDMS). The binding of concanavalin A to a lectin-dextran and a glycoproteinacetylcholinesterase has been used to demonstrate the homogeneous, ratioing format of fluorescence polarization for the quick and accurate determination of extremely low (nanomole) concentrations. Polarization has also been used to sense for a poly-aromatic hydrocarbon (PAH) within a microfluidic channel using binding to an antibody. We have also demonstrated a simple pH sensor based on the change in anisotropy of a pH sensitive fluorophore. The ease of fabrication and measurement using such polarization-based devices make them extremely suitable for micro-sized sensors, assays and total analysis systems.
From BioMEMS to Bionanotechnology: Integrated BioChips for the Detection of Cells and Microorganisms
Authors: Bashir R. , Akin D. , Gómez R. , Li H. , Chang W.J. , Gupta A. 
Published: June 2019

AbstractThis paper reviews the interdisciplinary work performed in our group in recent years to develop micro-integrated devices to characterize biological entities. We present the use of electrical and mechanically based phenomena to perform characterization and various functions needed for integrated biochips. One sub-system takes advantage of the dielectrophoretic effect to sort and concentrate cells within a micro-fluidic biochip. Another sub-system measures impedance changes produced by the metabolic activity of cells to determine their viability. A third sub-system is used to detect the mass of bacteria as they bind to micro-mechanical silicon cantilevers. These devices with an electronic signal output can be very useful in producing practical systems for rapid detection and characterization of cells for a wide variety of applications in the food safety and health diagnostics industries.
Surface Modification for Protein Resistance Using a Biomimetic Approach
Authors: Dalsin Jeffrey L. , Messersmith Phillip B. 
Published: June 2019

AbstractIn recent years the immobilization of poly(ethylene glycol) (PEG) on surfaces has proved to be one of the most attractive methods to prevent biological fouling of surfaces. We have developed a paradoxical biomimetic PEGylation strategy that exploits the adhesive characteristics of proteins secreted by marine mussels—one of nature's most notorious foulers. Linear PEGs were coupled to peptides containing 3,4-dihydroxyphenylalanine (DOPA), an unusual amino acid which is found in high concentration in these so-called mussel adhesive proteins. Using surface plasmon resonance, we have demonstrated enhanced resistance to protein adhesion on gold substrates modified with the DOPA-containing PEGs.
Mimicking the Formation of Biomineral Composites through Deposition of Calcium Carbonate Thin-Films on Modified Fiber Net Templates
Authors: Ajikumar Parayil Kumaran , Lakshminarayanan Rajamani , Suresh Valiyaveettil 
Published: June 2019

AbstractThin films of calcium carbonate were deposited on the surfaces of synthetic substrates using a simple biomimetic pathway. The Nylon 66 fiber knit pre-adsorbed with acidic polymers was used as a template for the controlled deposition of CaCO3 thin film. The presence of the soluble macromolecules on the fiber knit surface was characterized using ATR-FTIR spectroscopy. The characterization of the mineral films was carried out using scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive Xray scattering (EDX) studies.
Reconfigurable Hydrophobic/Hydrophilic Surfaces Based on Self-Assembled Monolayers
Authors: Deval Joanne , Umali Teodoro A. , Spencer Brandee L. , Lan Esther H. , Dunn Bruce , Ho Chih-Ming 
Published: June 2019

AbstractThe fabrication of micron-scale channels and reaction chambers using micromachining techniques has created devices with large surface to volume ratios. As a result, surface properties play a major role in determining the behavior of micromachined devices. In this work, we present strategies that can be used to reconfigure surfaces from hydrophobic to hydrophilic or from hydrophilic to hydrophobic. The reversible nature of the surface is made possible by using deposition and removal of biomolecules or amphiphiles on self-assembled monolayers (SAMs). When the initial surface was hydrophobic (using a CH3-terminated SAM on the surface, water contact angle ∼100), it was rendered hydrophilic (water contact angle ≤60°) using monolayer adsorption of avidin protein. To retrieve the hydrophobicity, the avidin was subsequently removed using non-ionic surfactant octyl-β-D-glucopyranoside. Moreover, by incorporating a biotinylated poly(ethyleneglycol), the avidin-coated surface was resistant to further non-specific adsorption. If the initial surface was hydrophilic (using a CO2H-terminated SAM on the surface, water contact angle ≤20°), it was rendered hydrophobic (water contact angle >90°) using monolayer amphiphilic octadecylamine adsorption. The hydrophilicity was restored after subsequently removing the amphiphile using anionic surfactant sodium lauryl sulfate. Both types of surfaces showed excellent reversibility and demonstrated the ability to control surface wettability.
Intrafibrillar Mineralization of Collagen using a Liquid-Phase Mineral Precursor
Authors: Olszta Matthew J. , Douglas Elliot P. , Gower Laurie B. 
Published: June 2019

AbstractIntrafibrillar mineralization of type-I collagen with hydroxyapatite (HA) is the basis of the complex biological composite known as bone, which from a material science perspective is a fascinating example of an interpenetrating bioceramic composite. Using a polymer-induced liquid-precursor (PILP) process, collagen substrates were highly infiltrated with a liquid-phase mineral precursor to calcium carbonate (CaCO3). At sections of partially mineralized collagen, banded mineral patterns were observed perpendicular to the collagen fibrils, while other fibrils were completely mineralized. An acid etch, used to preferentially remove superficial mineral, further revealed such banded patterns in fully mineralized samples. Removal of the collagen matrix with a dilute hypochlorite solution showed an interpenetrating mineral phase, with mineral disks that spanned the diameter of the pre-existing collagen fibrils, supporting our hypothesis that intrafibrillar mineralization can be achieved via capillary action applied to a liquid-phase mineral precursor.