Modification of structural, thermal and optical properties of PC-PET/CdSe NCP using gamma radiation

2021 ◽  
Author(s):  
Radiyah A. Bahareth ◽  
Kaoutar Benthami ◽  
Ali A. Alhazime ◽  
Samir A. Nouh
Keyword(s):  
Optical Properties ◽  
Gas Flow ◽  
Color Difference ◽  
Lattice Parameter ◽  
Ex Situ ◽  
Polybutylene Terephthalate ◽  
Amorphous Content ◽  
Degradation Temperature ◽  
Average Grain Size ◽  
Gamma Irradiated

In the current study we synthesized a nanocomposite (NCP) from polycarbonate/polybutylene terephthalate (PC-PET) blend and CdSe nanoparticles (NPs) through ex-situ casting methodology. CdSe NPs were synthesized using thermolysis technique with N2 gas flow. X-ray diffraction data for CdSe NPs are reported. The Rietveld refinement indicated that the synthesized CdSe acclimatizes cubic zinc blends constitution of a lattice parameter 6.057 Å and an average grain size of 2 nm. The PC-PET/CdSe NCP samples were irradiated by gamma doses between 20 and 230 kGy. The induced variations in the structure, thermal and optical properties of the gamma irradiated PC-PET/CdSe NCP have been illustrated by means of TEM, XRD, TGA, FTIR and UV-vis spectroscopes. The irradiation with doses in the range 50-230 kGy leads to the domination of crosslinking that improves the amorphous content. This increases the degradation temperature from 417 to 432oC indicative of an enhancement in the thermostability of the NCP samples. Also, the optical band gap is reduced from 4.28 to 3.76 eV which is ascribed to the enhancement in the amorphous content of the irradiated PC-PET/CdSe NCP. This specifies that the gamma irradiation causes a more compactness of the NCP and leads to appropriate spreading of CdSe NPs within the PC-PET matrix. Additionally, the CIE approach was used to describe the colored samples. It is found that the PC-PET/CdSe NCP acquires color due to gamma doses, as the color intensity reached a remarkable color difference larger than 5 (14.9) which is a reasonable challenge in saleable reproduction on printing press.

Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20402
Author(s):  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Color Difference ◽  
Band Gap Energy ◽  
Polybutylene Terephthalate ◽  
Γ Irradiation ◽  
Gap Energy ◽  
Vis Spectroscopy ◽  
Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

Gamma induced changes in Makrofol/CdSe nanocomposite films

2022 ◽  
Author(s):  
Ali A. Alhazime ◽  
M. ME. Barakat ◽  
Radiyah A. Bahareth ◽  
E. M. Mahrous ◽  
Saad Aldawood ◽  
...  
Keyword(s):  
Gas Flow ◽  
Lattice Parameter ◽  
Cdse Nanoparticles ◽  
Nanocomposite Films ◽  
Ex Situ ◽  
Γ Irradiation ◽  
Dielectric Parameters ◽  
Zinc Blend ◽  
X Ray ◽  
Induced Changes

Abstract In our present work, we applied ex-situ casting procedure to prepare a nanocomposite (NCP) from Makrofol polycarbonate (PC) and CdSe nanoparticles. The CdSe nanoparticles were prepared by thermolysis procedure in the presence of N2 gas flow. Rietveld refinement of x-ray data illustrated that the CdSe accustoms cubic zinc blend structure of a 6.057 Å lattice parameter and 2 nm typical grain size. Samples from the prepared NCP were exposed to γ dosages (20-250 kGy). The modifications induced in the NCP films owing to γ dosages have been studied. The γ irradiation (50-250 kGy) causes the crosslinks that reduces the optical bandgap from 4.15 to 3.81 eV; associated with an increase in dielectric parameters and refractive index. This is attributed to the increase of the mass fraction of the disordered regions as specified by XRD. The PC-CdSe NCP was found to have reaction to color modification which makes it suitable in saleable reproduction on printing press.

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.

Influence of Excess Bi2O3 and Na2Co3 on Crystal Structure and Microstructure of Bismuth Sodium Titanate Ceramics

2011 ◽  
Vol 474-476 ◽  
pp. 1711-1714 ◽  
Author(s):  
Panadda Sittiketkron ◽  
Arrak Klinbumrung ◽  
Theerachai Bongkarn
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Perovskite Phase ◽  
Average Particle Size ◽  
Sodium Titanate ◽  
Solid State Reaction Method ◽  
Lattice Parameter ◽  
Rhombohedral Structure ◽  
Average Particle ◽  
Average Grain Size

This study investigated the influence of excess Bi2O3 and Na2CO3 on the crystal structure, microstructure and dielectric properties of (Bi0.5Na0.5)TiO3 (BNT) ceramics. The BNT ceramics were synthesized using the solid-state reaction method with various excess Bi2O3 and Na2CO3 levels (0, 1, 2, 3 and 4 mol%). The X-ray characterization revealed that all samples had a rhombohedral structure. A pure perovskite phase was obtained in all samples. The lattice parameter a tended to increase with increased excess Bi2O3 and Na2CO3 content in the calcined powders and sintered ceramics. The average particle size increased while, the average grain size tended to decreased with increased of excess Bi2O3 and Na2CO3 content. The depolarization temperature (Td) and the Curie temperature (Tc) were slightly decreased with the increase of excess Bi2O3 and Na2CO3 content. The dielectric properties were related to the density.

Post-irradiation effects on gamma-irradiated nylon 6,12 fibers

2013 ◽  
Vol 33 (9) ◽  
pp. 823-828 ◽  
Author(s):  
Carmina Menchaca-Campos ◽  
Gonzalo Martínez-Barrera ◽  
Héctor López-Valdivia ◽  
Héctor Carrasco ◽  
Alberto Álvarez-Castillo
Keyword(s):  
Melting Point ◽  
Storage Time ◽  
Chain Scission ◽  
Degree Of Crystallinity ◽  
Irradiation Effects ◽  
Post Irradiation ◽  
Degradation Temperature ◽  
Optical Images ◽  
Gamma Irradiated ◽  
Irradiation Process

Abstract Post-irradiation effects on nylon 6,12 crystalline fibers gamma-irradiated 6 years previously (6YI) were studied, including thermal stability and morphology; their relationship with storage time was also studied. The results of these studies were compared with those obtained for non-irradiated (NI) and namely freshly irradiated (FI) crystalline fibers. The results include analyses like thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM) and optical images for (6YI and FI) both kinds of nylon 6,12 fibers. The results showed that the most prominent effect is related to the reaction progress. The chain scission and/or crosslinking mechanisms, as well as the free radicals, allow proceeding with the reaction, and consequently, changes on the properties of the FI samples. The melting point, degree of crystallinity, degradation temperature and morphology prove that additional chemical reactions and surface modifications keep occurring in the fibers long after the irradiation process has ended. With storage time, the surface becomes rougher, the color turns yellowish, the melting point diminishes and the degree of crystallinity increases.

Hydrogen Release and Si-N Bond-Healing Infrared Study of Rapid Thermal Annealed Amorphous Silicon Nitride Thin Films

1995 ◽  
Vol 398 ◽  
Author(s):  
P. Santos-Filho ◽  
G. Stevens ◽  
Z. Lu ◽  
K. Koh ◽  
G. Lucovsky
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Gas Flow ◽  
Structural Changes ◽  
Thermal Dissociation ◽  
Chemical Vapor ◽  
Hydrogen Release ◽  
Ex Situ ◽  
Infrared Study ◽  
Amorphous Silicon Nitride

ABSTRACTWe address aspects of hydrogen bonding and its thermal evolution in amorphous Silicon nitride films grown by Remote Plasma Enhanced Chemical Vapor Deposition (RPECVD) from SiH4 and NH3 (or ND3) source gases. Rapid Thermal Annealing (RTA) decreases the Si-H(D) and SiN-H(D) bond populations. The hydrogen bonds break, and H2 (HD, D2) forms and evolves from the film with the heat treatment. This molecular hydrogen release is accompanied by Si- and N- bond healing as detected by a SiN infra red stretch mode signal gain. The ex-situ RTA experiment temperatures ranged from 400 °C to 1200 °C, in 100 °C steps and the film structural changes were monitored by Fourier Transform Infrared spectroscopy (FTIR) after each incremental anneal. Gas flow ratios R=NH3/SiH4 > 2 produced films in which SiN-H(D) bonds dissociated, and a gas desorption rate equation estimated an activation energy barrier of Ea = 0.3 eV. The release of hydrogen from the films in the form of H2 (D2) and ammonia radicals was detected by mass spectrometry and is shown here. The re-bonding of nitrogen to silicon upon thermal dissociation of hydrogen's is consistent with the improvement of the electrical properties of a-SiN:H films following RTA treatment.

Influence of Substrate Temperature on Structural and Optical Properties of Co-Evaporated Cu2SnS3/ITO Thin Films

2022 ◽  
Vol 1048 ◽  
pp. 189-197
Author(s):  
Tippasani Srinivasa Reddy ◽  
M.C. Santhosh Kumar
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Substrate Temperature ◽  
Indium Tin Oxide ◽  
Nir Spectroscopy ◽  
Stoichiometric Ratio ◽  
Tin Sulfide ◽  
Structural And Optical Properties ◽  
Average Grain Size ◽  
Deposited Films

In this study report the structural and optical properties of Copper Tin Sulfide (Cu2SnS3) thin films on indium tin oxide (ITO) substrate using co-evaporation technique. High purity of copper, tin and sulfur were taken as source materials to deposit Cu2SnS3 (CTS) thin films at different substrate temperatures (200-350 °C). Further, the effect of different substrate temperature on the crystallographic, morphological and optical properties of CTS thin films was investigated. The deposited CTS thin films shows tetragonal phase with preferential orientation along (112) plane confirmed by X-ray diffraction. Micro-Raman studies reveled the formation of CTS thin films. The surface morphology, average grain size and rms values of the deposited films are examined by Scanning electron spectroscopy (SEM) and Atomic Force Microscopy (AFM). The Energy dispersive spectroscopy (EDS) shows the presence of copper, tin and sulfur with a nearly stoichiometric ratio. The optical band gap (1.76-1.63 eV) and absorption coefficient (~105 cm-1) of the films was calculated by using UV-Vis-NIR spectroscopy. The values of refractive index, extinction coefficient and permittivity of the deposited films were calculated from the optical transmittance data.

Effect of Nitrogen Doping on the Structure and Optical Properties of N-Type Hydrogenated Amorphous Silicon Thin Films

2011 ◽  
Vol 383-390 ◽  
pp. 6980-6985
Author(s):  
Mao Yang Wu ◽  
Wei Li ◽  
Jun Wei Fu ◽  
Yi Jiao Qiu ◽  
Ya Dong Jiang
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Amorphous Silicon ◽  
Photoelectron Spectroscopy ◽  
Gas Flow ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Silicon Thin Films ◽  
Frequency Plasma ◽  
Hydrogenated Amorphous

Hydrogenated amorphous silicon (a-Si:H) thin films doped with both Phosphor and Nitrogen are deposited by ratio frequency plasma enhanced chemical vapor deposition (PECVD). The effect of gas flow rate of ammonia (FrNH3) on the composition, microstructure and optical properties of the films has been investigated by X-ray photoelectron spectroscopy, Raman spectroscopy and ellipsometric spectra, respectively. The results show that with the increase of FrNH3, Si-N bonds appear while the short-range order deteriorate in the films. Besides, the optical properties of N-doped n-type a-Si:H thin films can be easily controlled in a PECVD system.

Tuning Hierarchical Cluster Assembly in Pulsed Laser Deposition of Al-doped ZnO

2013 ◽  
Vol 1497 ◽  
Author(s):  
Paolo Gondoni ◽  
Valeria Russo ◽  
Carlo E. Bottani ◽  
Andrea Li Bassi ◽  
Carlo S. Casari
Keyword(s):  
Optical Properties ◽  
Pulsed Laser Deposition ◽  
Gas Flow ◽  
Mass Density ◽  
Pulsed Laser ◽  
Hierarchical Cluster ◽  
Laser Deposition ◽  
Cluster Assembly ◽  
Hierarchical Assembly ◽  
Doped Zno

ABSTRACTThe synthesis of hierarchically assembled Al-doped ZnO layers by Pulsed Laser Deposition (PLD) at room temperature was investigated. PLD was performed in a background pressure of 100 Pa O2 to deposit clusters in a low energy regime and obtain nano- and mesostructures resulting from a hierarchical assembly of nanoclusters. We here analyzed the effects of varying the gas flow rate on mesoscale morphology, mass density and optical properties. The variation of the target-to-substrate distance was also investigated, identifying its effects on mass density and film morphology. The optimization of optical properties in terms of transparency and light scattering capability is of potential interest for photovoltaic applications.

Material and optical properties of GaAs grown on (001) Ge/Si pseudo-substrate

2004 ◽  
Vol 809 ◽  
Author(s):  
Yves Chriqui ◽  
Ludovic Largeau ◽  
Gilles Patriarche ◽  
Guillaume Saint-Girons ◽  
Sophie Bouchoule ◽  
...  
Keyword(s):  
Optical Properties ◽  
Dislocation Density ◽  
High Speed ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Lattice Parameter ◽  
Photoluminescence Intensity ◽  
High Quality ◽  
Light Emitting ◽  
Thermal Expansion Coefficients

ABSTRACTOne of the major challenges during recent years was to achieve the compatibility of III-V semiconductor epitaxy on silicon substrates to combine opto-electronics with high speed circuit technology. However, the growth of high quality epitaxial GaAs on Si is not straightforward due to the intrinsic differences in lattice parameters and thermal expansion coefficients of the two materials. Moreover, antiphase boundaries (APBs) appear that are disadvantageous for the fabrication of light emitting devices. Recently the successful fabrication of high quality germanium layers on exact (001) Si by chemical vapor deposition (CVD) was reported. Due to the germanium seed layer the lattice parameter is matched to the one of GaAs providing for excellent conditions for the subsequent GaAs growth. We have studied the material morphology of GaAs grown on Ge/Si PS using atomic layer epitaxy (ALE) at the interface between Ge and GaAs. We present results on the reduction of APBs and dislocation density on (001) Ge/Si PS when ALE is applied. The ALE allows the reduction of the residual dislocation density in the GaAs layers to 105 cm−2 (one order of magnitude as compared to the dislocation density of the Ge/Si PS). The optical properties are improved (ie. increased photoluminescence intensity). Using ALE, light emitting diodes based on strained InGaAs/GaAs quantum well as well as of In(Ga)As quantum dots on an exactly oriented (001) Ge/Si pseudo-substrate were fabricated and characterized.

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