Improving photoluminescence, optical and electrical characteristics of PMMA films with gamma irradiation

2021 ◽  
Author(s):  
M.F. Zaki ◽  
Nasser Shubayr ◽  
Reda M Radwan ◽  
Yazeed Alashban
Keyword(s):  
Gamma Irradiation ◽  
Polymeric Materials ◽  
Advanced Materials ◽  
Strong Impact ◽  
Electrical Characteristics ◽  
Electrical Measurements ◽  
Indirect Transition ◽  
Dielectric Parameters ◽  
Vis Spectroscopy ◽  
Gamma Irradiated

Abstract Polymeric materials are macromolecules, essentially a combination of numerous repeated subunits. Polymers are innovative and advanced materials that currently have a strong impact on our daily lives. In recent years, polymer use has been prominent due to the materials’ distinctive properties; thus, they entered different fields of science, technology and industrial-biomedical applications.The improvement of photoluminescence, optical and electrical characteristics of non-conducting Poly(methyl methacrylate) (PMMA) films was studied. Upon gamma irradiation of various doses, the photophysical and electrical properties of PMMA films were investigated using photoluminescence spectroscopy, ultraviolet–visible (UV-Vis) spectroscopy and the LCR Meter Bridge Circuit technique. The fluorescent response improved the photoluminescence (PL) spectral emission peaks according to gamma values. Strong fluorescence peaks appeared with the highest gamma dose. The UV–Vis results revealed a significant red-shift in the absorption edge as gamma doses increased. This shift exhibits a continuous decrease in the energy band gap values (from 3.50 to 2.60 eV for direct transition and from 3.05 to 1.55 eV for indirect transition). This was due to the formation of carbon clusters, which led to an increase in the electrical conductivity and improved the dielectric parameters of the irradiated PMMA films. Among a variety of measurements presented and discussed in the present study, the electrical measurements showed improved electrical characteristics of gamma-irradiated PMMA films.

scholarly journals State-of-the-Art Modification of Plastic Aggregates Using Gamma Irradiation and Its Optimization for Application to Cementitious Composites

2021 ◽  
Vol 11 (21) ◽  
pp. 10340
Author(s):  
Heonseok Lee ◽  
Hyeonwook Cheon ◽  
Yonghak Kang ◽  
Seungjun Roh ◽  
Woosuk Kim
Keyword(s):  
Compressive Strength ◽  
Gamma Irradiation ◽  
Performance Improvement ◽  
Mechanical Performance ◽  
State Of The Art ◽  
Chemical Properties ◽  
Polymeric Materials ◽  
Cementitious Composites ◽  
Gamma Irradiated ◽  
And Chemical Properties

In the past few decades, there have been numerous attempts to add plastic aggregates composed of polymeric materials to cementitious composites, either as an alternative to using natural aggregates or as fillers and fibers. However, the addition of plastic aggregates often results in cementitious composites with lower mechanical performance. In this paper, we attempt to address this issue by applying gamma irradiation technology to restore the mechanical performance. We aimed to determine the optimal gamma irradiation and mixing combinations by comparing the experimental results with information summarizing the recent literature related to the use of gamma-irradiated plastic aggregates within cementitious composites. To this end, the effects of changes in the physical and chemical properties of plastics due to irradiation with gamma irradiation on the strength of cementitious composites were evaluated using irradiation doses of 25, 50, 75, and 100 kGy and various plastic materials as key parameters. In the compressive strength test, it was found that adding gamma-irradiated plastic increased the compressive strength of the cementitious composites compared to the nonirradiated plastic. This suggests that the irradiation of plastic aggregates with gamma rays is an effective method to recover some of the strength lost when plastic aggregates are added to cementitious composites. In addition, modifications in the microstructure and chemical properties of the gamma-irradiated plastic were analyzed through SEM and FT-IR analysis, which allowed the determination of the strength enhancement mechanism. The results of this study show the possibility of the state-of-the-art performance improvement method for using plastic aggregate as a substitute for natural aggregate, going further from the plastic performance improvement technology for limited materials and radiation dose presented in previous studies.

scholarly journals Structural and Optical Investigations of Radiation Damage in Transparent PET Polymer Films

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Shiv Govind Prasad ◽  
Abhijit De ◽  
Udayan De
Keyword(s):  
Free Radicals ◽  
Gamma Irradiation ◽  
Polymer Films ◽  
Wavelength Region ◽  
Xrd Analysis ◽  
High Dose ◽  
Plane Vibration ◽  
Bending Mode ◽  
Vis Spectroscopy ◽  
Gamma Irradiated

Effects of gamma irradiation at different doses up to 135 kGy on polyethylene terephthalate (PET) polymer films have been investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and ultraviolet-visible (UV-VIS) spectroscopy. From XRD analysis, it was found that even at a high dose of gamma irradiation of 135 kGy, crystallinity of the PET samples remain unchanged. However, the FTIR peak at 871 cm−1 (depicting C–H bending mode of out-of-plane vibration) and another at 1303 cm−1 (representing C–H bending mode of in-plane vibration) disappear for gamma-irradiated PET. In this study, it has also been found that γ-irradiation in air enhances the optical absorption in the wavelength region 320–370 nm. This has been attributed to free radicals being produced in the polymer by the γ-radiation. Further, the free radicals react with oxygen of air to form carbonyl group and hydroxyls. With increasing γ-dose, there is a red shift of the UV—near visible cutoff for PET. XRD and FTIR observations on γ-damage have been correlated.

scholarly journals Electrical characteristics of PVA-PANI-ZnS nanocomposite film synthesized by gamma irradiation method

2018 ◽  
Vol 36 (1) ◽  
pp. 102-106 ◽  
Author(s):  
Afarin Bahrami ◽  
Kasra Behzad ◽  
Nastaran Faraji ◽  
Alireza Kharazmi
Keyword(s):  
Gamma Irradiation ◽  
Chemical Structure ◽  
Nanocomposite Films ◽  
Electrical Characteristics ◽  
Frequency Range ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Lcr Meter ◽  
Different Doses ◽  
Ft Ir Spectroscopy

Abstract This work presents the synthesis of PANI-PVA-ZnS nanocomposite films by gamma irradiation approach. The samples were irradiated with different doses ranging from 10 kGy to 40 kGy. Subsequently, structural, morphological, optical and electrical characteristics of the samples were investigated. Fourier transform infrared (FT-IR) spectroscopy was employed to study the chemical structure of the samples. Field emission scanning electron microscopy (FE-SEM) was used to investigate the morphology of nanocomposites. The electronic absorption characteristics of the samples were measured by means of UV-Vis spectroscopy. The AC and DC electrical behaviors of the samples were characterized using LCR meter in the frequency range of 20 Hz to 1 MHz. The impedance values of the samples were extracted from Cole-Cole plots and consequently DC conductivity was calculated.

Silicon Surface Chemical Treatments in Oxide/Nitride Dielectric Stack Properties

2002 ◽  
Vol 716 ◽  
Author(s):  
D. Jacques ◽  
S. Petitdidier ◽  
J.L. Regolini ◽  
K. Barla
Keyword(s):  
Oxygen Content ◽  
Oxide Thickness ◽  
Morphological Data ◽  
Electrical Characteristics ◽  
Electrical Measurements ◽  
Chemical Cleaning ◽  
Force Microscopy ◽  
Chemical Treatments ◽  
Atomic Force ◽  
Interfacial Oxygen

AbstractOxide/Nitride dielectric stack is widely used as the standard dielectric for DRAM capacitors. The influence of the chemical cleaning prior to the stack formation has been studied in this work. As a result, morphological data such as stack surface roughness (Atomic Force Microscopy) and silicon nitride (SiN) incubation time for growth are comparable for all the studied cases on <Si>. However, Tof-SIMS exhibits different oxygen content at the Si/stack interface following the different chemical treatments. Electrical measurements show comparable C-V and I-V results, for the same Equivalent Oxide Thickness (same capacitance at strong accumulation i.e.-3V) while the different studied interfaces bring different interface states density with lower values for higher interfacial oxygen content. For DRAM applications, a clear improvement in electrical characteristics is obtained under low interfacial oxygen content conditions. Results are compared in embedded-DRAM cells for which we developed an industrially compatible dielectric deposition sequence to obtain minimum leakage current with maximum specific capacitance and no particular linking constraints.

Effect of gamma radiation on the structural, thermal and optical properties of PMMA/Sn0.75Fe0.25S2 nanocomposite

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali A. Alhazime ◽  
Nesreen T. El-Shamy ◽  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Thermal Stability ◽  
Optical Properties ◽  
Gamma Irradiation ◽  
Optical Band Gap ◽  
Color Variation ◽  
Nanocomposite Films ◽  
Color Changes ◽  
Gamma Irradiated ◽  
Intermolecular Crosslinking ◽  
Amorphous Part

AbstractNanocomposite films of polymethylmethacrylate PMMA with Sn0.75Fe0.25S2 nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Changes in PMMA/Sn0.75Fe0.25S2 nanocomposite (NCP) due to gamma irradiation have been measured. XRD results indicate that the gamma doses of 10–80 kGy cause intermolecular crosslinking that reduces the ordered portion in the NPs. Bonding between the NPs and the host PMMA was confirmed by FTIR. TGA results indicate an enhancement in thermal stability in the NCP films irradiated with doses 20–80 kGy. The optical band gap was reduced from 3.23 to 2.47 eV upon gamma irradiation up to 80 kGy due bonding between the NPs and PMMA which enhanced the amorphous part of the NPs. Finally, the color variation between the blank and irradiated films (ΔE) was determined. Color changes immensely when the PMMA/Sn0.75Fe0.25S2 NCP films are gamma irradiated. Values of ΔE were as much as 31.6 which is an acceptable match in commercial reproduction on printing presses.

scholarly journals Facile Synthesis of L-Cysteine Functionalized Graphene Quantum Dots as a Bioimaging and Photosensitive Agent

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1879
Author(s):  
Mila Milenković ◽  
Aleksandra Mišović ◽  
Dragana Jovanović ◽  
Ana Popović Bijelić ◽  
Gabriele Ciasca ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Gamma Irradiation ◽  
Hela Cells ◽  
Graphene Quantum Dots ◽  
Morphological Properties ◽  
Paramagnetic Resonance ◽  
Chemical Reagents ◽  
Amino Amide ◽  
Gamma Irradiated ◽  
Electron Paramagnetic

Nowadays, a larger number of aggressive and corrosive chemical reagents as well as toxic solvents are used to achieve structural modification and cleaning of the final products. These lead to the production of residual, waste chemicals, which are often reactive, cancerogenic, and toxic to the environment. This study shows a new approach to the modification of graphene quantum dots (GQDs) using gamma irradiation where the usage of reagents was avoided. We achieved the incorporation of S and N atoms in the GQD structure by selecting an aqueous solution of L-cysteine as an irradiation medium. GQDs were exposed to gamma-irradiation at doses of 25, 50 and 200 kGy. After irradiation, the optical, structural, and morphological properties, as well as the possibility of their use as an agent in bioimaging and photodynamic therapy, were studied. We measured an enhanced quantum yield of photoluminescence with the highest dose of 25 kGy (21.60%). Both S- and N-functional groups were detected in all gamma-irradiated GQDs: amino, amide, thiol, and thione. Spin trap electron paramagnetic resonance showed that GQDs irradiated with 25 kGy can generate singlet oxygen upon illumination. Bioimaging on HeLa cells showed the best visibility for cells treated with GQDs irradiated with 25 kGy, while cytotoxicity was not detected after treatment of HeLa cells with gamma-irradiated GQDs.

Influence of gamma-irradiation on the electrical characteristics of diode structures based on GaAs

1982 ◽  
Vol 60 (1-4) ◽  
pp. 143-146 ◽  
Author(s):  
R. V. Konakova ◽  
Yu. A. Tkhorik ◽  
V. I. Shakhovtsov
Keyword(s):  
Gamma Irradiation ◽  
Electrical Characteristics

The effect of gamma irradiation on electrical characteristics of Au/polyvinyl alcohol (Co, Zn-doped)/n-Si Schottky barrier diodes

2010 ◽  
Vol 118 (1) ◽  
pp. 596-603 ◽  
Author(s):  
İ. Taşçıoğlu ◽  
H. Uslu ◽  
Ş. Altındal ◽  
P. Durmuş ◽  
İ. Dökme ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Gamma Irradiation ◽  
Schottky Barrier ◽  
Electrical Characteristics ◽  
Schottky Barrier Diodes

ESR of Gamma Irradiation Damage Centers in Single Crystals of Some Phenol Derivatives

1993 ◽  
Vol 48 (4) ◽  
pp. 560-562 ◽  
Author(s):  
F. Köksal ◽  
Ş. Osmanoğlu ◽  
R. Tapramaz
Keyword(s):  
Gamma Irradiation ◽  
Single Crystals ◽  
Irradiation Damage ◽  
Phenol Derivatives ◽  
Phenoxy Radicals ◽  
Gamma Irradiated

Abstract Phenoxy radicals have been observed and identified in gamma irradiated 2-t-bu-4-methylphenol, 2,6-di-t-bu-4-methylphenol and 2-amino-4-methylphenol single crystals.

Degradation and Reliability of Bare Dies Operated up to 300°C

2015 ◽  
Vol 821-823 ◽  
pp. 681-684
Author(s):  
Dean Hamilton ◽  
M. Jennings ◽  
Stephen York ◽  
Steven A. Hindmarsh ◽  
Y. Sharma ◽  
...  
Keyword(s):  
Cross Sections ◽  
Mechanical Degradation ◽  
Electrical Characteristics ◽  
Isothermal Heating ◽  
Electrical Measurements ◽  
Tem Analysis ◽  
Metal Layers ◽  
State Resistance ◽  
Contact Metal

In this paper, we demonstrate the degradation of commercially available 1.2kV SiC MOSFET bare dies subjected to long periods of isothermal heating at 300°C in air. Periodic electrical measurements indicated an increase in on-state resistance to different extents for three different vendor designs, and the discovery of a progressive rectifying type forward characteristic at low drain-source voltages. Subsequent investigations to determine the cause of the degraded electrical characteristics including sectioning and SEM/TEM analysis revealed some mechanical degradation within the device gate-source cross-sections and backside drain contact metal layers. While one vendor device was severely degraded after approximately 24 hours of heating, another vendor device was only just beginning to degrade after 100 hours, indicating that these devices may be used successfully in real applications at 300°C junction temperatures for relatively long periods.

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