Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 25 years of regular publishing 25 years of regular publishing 1408 10.29252/ijpr.19.1.1 FA Journal Article 2019 11 26 25 years of regular publishing Iranian Journal of Physics Research has been publishing since 1996. We are giving a short report on this experience and the progress of IJPR. 25 years of regular publishing Iranian Journal of Physics Research has been publishing since 1996. We are giving a short report on this experience and the progress of IJPR. regular publishing 25 years
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Design and fabrication of a prototype planar undulator Design and fabrication of a prototype planar undulator 1 17 1409 10.29252/ijpr.19.1.2 FA A Ramezani Moghaddam J Rahighi M Lamehi P Khodadoost Y Radkhorrami Journal Article 2019 11 26 The main goal of this work is to get the fabrication technology of the insertion devices. A prototype undulator with the period of 48mm and the peak magnetic field of 0.75 T has been fabricated using NdFeB-SH35 magnets based on the cooperation between ILSF and NSTRI. The total magnet length is 483 mm and the number of periods is 8. The magnetic parameters of the undulator are determined in order to reach the first and third harmonics. The photon energy should cover 260 eV to 2000 eV range. In order to control the strong attractive magnetic force between the upper and lower arrays, a special mechanical mechanism has been designed and fabricated. The source of errors in the magnetic field has been discussed. The share of each errors has been investigated in the total magnetic field and their effects on the harmonics intensity have been studied. The RMS field error has been obtained to be 0.4%; also, the first and third harmonics intensity reached to more than 80% of the ideal intensities in the presence of the real magnetic field. The main goal of this work is to get the fabrication technology of the insertion devices. A prototype undulator with the period of 48mm and the peak magnetic field of 0.75 T has been fabricated using NdFeB-SH35 magnets based on the cooperation between ILSF and NSTRI. The total magnet length is 483 mm and the number of periods is 8. The magnetic parameters of the undulator are determined in order to reach the first and third harmonics. The photon energy should cover 260 eV to 2000 eV range. In order to control the strong attractive magnetic force between the upper and lower arrays, a special mechanical mechanism has been designed and fabricated. The source of errors in the magnetic field has been discussed. The share of each errors has been investigated in the total magnetic field and their effects on the harmonics intensity have been studied. The RMS field error has been obtained to be 0.4%; also, the first and third harmonics intensity reached to more than 80% of the ideal intensities in the presence of the real magnetic field. planar undulator permanent magnets synchrotron radiation field error Hall probe
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 The simultaneous effect of 3d impurities of transition metals and oxygen vacancy defect on TiO2 anatase and rutile The simultaneous effect of 3d impurities of transition metals and oxygen vacancy defect on TiO2 anatase and rutile 19 30 1410 10.29252/ijpr.19.1.3 FA S M Esfandfard M R Elahifard R Behjatmanesh-Ardakani H Kargar Journal Article 2019 11 26 In this work, the formation of oxygen-vacancy defect in 3d metals-doped TiO2 anatase and rutile structures is first investigated. The systematic calculations of formation energy, crystalline stability, band structure and density of state (DOS) of TiO2 samples of anatase and rutile doped with 3d transition metals with and without oxygen defect is done using FHI-aims as a software package based on the density functional theory. The results of this research show that 3d impurities can influence the formation energy of O-vacancy defect noticeably, where all studied dopants except Mn and Zn diminish the formation energy of O-vacancy, leading to a higher activity. Also, among 3d transition matals, only Fe impurity in the presence of O-vacancy shows an inhibitor effect for the transition phase of anatase to rutile. The results of the band structure and DOS also show that the presence of O-vacancy defect in both anatase and rutile phases, in addition to creating occupied defect states under the conduction band, can lead to the appearance of a semiconductor of type n, as well as increasing the original band gap. Also, with O-vacancy, the presence of 3d impurities create defect states shifted to a lower energy from the conduction band to the valance band by increasing the atomic number of impurities. Here, with Fe, Ni, Co and Cu impurities, defect states appear inside the band gap, extending the exciting range of TiO2 photocatalyst to the visible region. The analysis of partial DOS also shows that the 3d orbital of impurities has the main contribution to the defect states.   In this work, the formation of oxygen-vacancy defect in 3d metals-doped TiO2 anatase and rutile structures is first investigated. The systematic calculations of formation energy, crystalline stability, band structure and density of state (DOS) of TiO2 samples of anatase and rutile doped with 3d transition metals with and without oxygen defect is done using FHI-aims as a software package based on the density functional theory. The results of this research show that 3d impurities can influence the formation energy of O-vacancy defect noticeably, where all studied dopants except Mn and Zn diminish the formation energy of O-vacancy, leading to a higher activity. Also, among 3d transition matals, only Fe impurity in the presence of O-vacancy shows an inhibitor effect for the transition phase of anatase to rutile. The results of the band structure and DOS also show that the presence of O-vacancy defect in both anatase and rutile phases, in addition to creating occupied defect states under the conduction band, can lead to the appearance of a semiconductor of type n, as well as increasing the original band gap. Also, with O-vacancy, the presence of 3d impurities create defect states shifted to a lower energy from the conduction band to the valance band by increasing the atomic number of impurities. Here, with Fe, Ni, Co and Cu impurities, defect states appear inside the band gap, extending the exciting range of TiO2 photocatalyst to the visible region. The analysis of partial DOS also shows that the 3d orbital of impurities has the main contribution to the defect states.   TiO2-based photocatalysts anatase and rutile oxygen-vacancy defect 3d-transition matals band structure and density of state
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 A fiber optic sensor for measuring glucose in aqueous solutions A fiber optic sensor for measuring glucose in aqueous solutions 31 36 1411 10.29252/ijpr.19.1.4 FA M R Amani Pour A Mazaheri B Nazari Journal Article 2019 11 26 In this paper, the set-up of a multi-mode fiber optic sensor for measuring glucose in aqueous solutions is investigated and evaluated. The basis of this sensor is based on the Fresnel Reflection. In this setup, a helium-neon laser is used as a light source, a fiber optic probe, photocell as detector and a digital multimeter. The statistical analysis of the recorded data shows a highly linear behavior in the range of 2 to 25 mM in the glucose solution. The sensitivity and detection limit of this fiber optic sensor are 11.4 mV/mM  and 2.5 mM, respectively. In this paper, the set-up of a multi-mode fiber optic sensor for measuring glucose in aqueous solutions is investigated and evaluated. The basis of this sensor is based on the Fresnel Reflection. In this setup, a helium-neon laser is used as a light source, a fiber optic probe, photocell as detector and a digital multimeter. The statistical analysis of the recorded data shows a highly linear behavior in the range of 2 to 25 mM in the glucose solution. The sensitivity and detection limit of this fiber optic sensor are 11.4 mV/mM  and 2.5 mM, respectively. Multi – mode fiber optic sensor Glucose solution Fresnel reflection
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Elastic constants and their variation by pressure in the cubic PbTiO3 compound using IRelast computational package within the density functional theory Elastic constants and their variation by pressure in the cubic PbTiO3 compound using IRelast computational package within the density functional theory 37 48 1412 10.29252/ijpr.19.1.5 FA R Ebrahimi-Jaberi; J Nematollahi H Gharagoozloo S Jalali-Asadabadi M Jamal Journal Article 2019 11 26 p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; text-align: justify; font: 12.0px 'Times New Roman'} span.s1 {font: 12.0px 'B Nazanin'} p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; text-align: justify; font: 12.0px 'Times New Roman'} span.s1 {font: 12.0px 'B Nazanin'} In this paper, we study the structural and electronic properties of the cubic PbTiO3 compound by using the density functional theory. For the calculation of band structure and density of states, we use the modified Becke–Johnson exchange potential proposed by Tran and Blaha (TB-mBJ), including the relativistic spin-orbit coupling (SOC). The results obtained from TB-mBJ functional and SOC calculations show that the calculated band gap is 2.18 eV. IRelast computational package is very recently implemented into the WIEN2k code and can be used to calculate the elastic constants of the crystal structures, where IR stands for Iran. We calculate the elastic constants of this compound by the IRelast code using the PBE-GGA, PBEsol-GGA, LDA, BPW91 and Engel-Vosko functionals. Then, by these elastic constants, we obtain some other related physical quantities such as shear constant, bulk modulus, Young’s modulus and Poisson’s ratio. Furthermore, we calculate the ductility of the compound under question. The calculated ductility shows that our compound is formable and not fragile. The effect of pressure on the elastic constants shows that C11, C12 and C44 are increased as the pressure is raised inside the considered pressure interval. Furthermore, the longitudinal and transverse sound velocities are derived for the compound using its calculated elastic constants. The results, therefore, show that the sound velocities, like elastic constants, are increased as pressure is raised . p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; text-align: justify; font: 12.0px 'Times New Roman'} span.s1 {font: 12.0px 'B Nazanin'} p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; text-align: justify; font: 12.0px 'Times New Roman'} span.s1 {font: 12.0px 'B Nazanin'} In this paper, we study the structural and electronic properties of the cubic PbTiO3 compound by using the density functional theory. For the calculation of band structure and density of states, we use the modified Becke–Johnson exchange potential proposed by Tran and Blaha (TB-mBJ), including the relativistic spin-orbit coupling (SOC). The results obtained from TB-mBJ functional and SOC calculations show that the calculated band gap is 2.18 eV. IRelast computational package is very recently implemented into the WIEN2k code and can be used to calculate the elastic constants of the crystal structures, where IR stands for Iran. We calculate the elastic constants of this compound by the IRelast code using the PBE-GGA, PBEsol-GGA, LDA, BPW91 and Engel-Vosko functionals. Then, by these elastic constants, we obtain some other related physical quantities such as shear constant, bulk modulus, Young’s modulus and Poisson’s ratio. Furthermore, we calculate the ductility of the compound under question. The calculated ductility shows that our compound is formable and not fragile. The effect of pressure on the elastic constants shows that C11, C12 and C44 are increased as the pressure is raised inside the considered pressure interval. Furthermore, the longitudinal and transverse sound velocities are derived for the compound using its calculated elastic constants. The results, therefore, show that the sound velocities, like elastic constants, are increased as pressure is raised . density functional theory band structure density of states elastic constants sound velocities
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Investigation of electron correlation effects in armchair silicene nanoribbons Investigation of electron correlation effects in armchair silicene nanoribbons 49 59 1413 10.29252/ijpr.19.1.6 FA F Bagherpour B Abediravan Journal Article 2019 11 26 In this study, the electronic structure of armchair silicene nanoribbons (ASiNRs) is investigated for various widths using first-principle calculations and the framework of the density functional theory. Electronic structure of ASiNRs shows a direct band gap which is decreased  with increasing the nanoribbon's width, showing an oscillatory behavior. The effective Coulomb interaction between localized electrons plays an important role in describing the reason underlying the electronic and magnetic ordering of the material, as well as the intensity of the correlation effects. Thus, we further investigate the screening of the Coulomb interaction in ASiNRs by employing ab initio calculations in conjunction with the constrained random-phase approximation (cRPA) and determine the values of  effective on-site Coulomb interaction (Hubbard U) for them. The values of  Hubbard U parameters for ASiNRs are significant and more than the ones in pristine silicene, indicating a strong correlation effect in these compounds. According to the intensity of different quantum confinement effects in these nanoribbons, the values of  on-site Coulomb interaction parameters, similar to the previous results, turn out to be small, which vary as a function of increasing the ribbon widths. Moreover, in the edge of nanoribbon, the effective Coulomb interaction patameters are greater than the inner parts, showing   the lower screening of  the Coulomb interaction between the localized electrons in the edge of nanoribbon. Finally, the results of the study of the off-site Coulomb interaction show that the Coulomb interaction is weakly screened at short distances, while at large distances if about 12 Å, it is unscreened, which is in a good agreement with the recent studies on the  low dimensional systems. This inefficient screening at large distances can explain the existence of a remarkable quasiparticles correction in GW approximation and exciton binding energy in ASiNRs.   In this study, the electronic structure of armchair silicene nanoribbons (ASiNRs) is investigated for various widths using first-principle calculations and the framework of the density functional theory. Electronic structure of ASiNRs shows a direct band gap which is decreased  with increasing the nanoribbon's width, showing an oscillatory behavior. The effective Coulomb interaction between localized electrons plays an important role in describing the reason underlying the electronic and magnetic ordering of the material, as well as the intensity of the correlation effects. Thus, we further investigate the screening of the Coulomb interaction in ASiNRs by employing ab initio calculations in conjunction with the constrained random-phase approximation (cRPA) and determine the values of  effective on-site Coulomb interaction (Hubbard U) for them. The values of  Hubbard U parameters for ASiNRs are significant and more than the ones in pristine silicene, indicating a strong correlation effect in these compounds. According to the intensity of different quantum confinement effects in these nanoribbons, the values of  on-site Coulomb interaction parameters, similar to the previous results, turn out to be small, which vary as a function of increasing the ribbon widths. Moreover, in the edge of nanoribbon, the effective Coulomb interaction patameters are greater than the inner parts, showing   the lower screening of  the Coulomb interaction between the localized electrons in the edge of nanoribbon. Finally, the results of the study of the off-site Coulomb interaction show that the Coulomb interaction is weakly screened at short distances, while at large distances if about 12 Å, it is unscreened, which is in a good agreement with the recent studies on the  low dimensional systems. This inefficient screening at large distances can explain the existence of a remarkable quasiparticles correction in GW approximation and exciton binding energy in ASiNRs.   armchair silicene nanoribbons cRPA density functional theory Hubbard U electronic correlation
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Optimization of 241Am-Be emission direction in neutron porosity tools for improving the precision in determining the porosity in calcite formation Optimization of 241Am-Be emission direction in neutron porosity tools for improving the precision in determining the porosity in calcite formation 61 68 1414 10.29252/ijpr.19.1.7 FA F Rahmani H Darvish Motevalli Journal Article 2019 11 26 Investigation of Hydrocarbon reservoir is important, so it is essential to predict and explore them precisely. One of the methods is well logging, which can transfer the probe or tool in the well to measure one or more characteristics. Nuclear well logging includes radioisotope source and at least one detector. In this work, emission direction of neutrons from the 241Am-Be neutron source toward the calcite formation has been investigated using MCNPX 2.6 to obtain the best precision in determining the liquid porosity. The results show that emission direction of 20 in degree with the resolution porosity of 3% in counts is recorded in detectors; as well; there is no decrease in depth penetration, providing speed of tools. Investigation of Hydrocarbon reservoir is important, so it is essential to predict and explore them precisely. One of the methods is well logging, which can transfer the probe or tool in the well to measure one or more characteristics. Nuclear well logging includes radioisotope source and at least one detector. In this work, emission direction of neutrons from the 241Am-Be neutron source toward the calcite formation has been investigated using MCNPX 2.6 to obtain the best precision in determining the liquid porosity. The results show that emission direction of 20 in degree with the resolution porosity of 3% in counts is recorded in detectors; as well; there is no decrease in depth penetration, providing speed of tools. nuclear well logging neutron source MCNPX 2.6 emission direction epithermal neutron detector
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Investigation of the magnetic interactions in Co2FeAl alloy nanoparticles using FORC analysis Investigation of the magnetic interactions in Co2FeAl alloy nanoparticles using FORC analysis 69 74 1415 10.29252/ijpr.19.1.8 FA S Alikhanzadeh-arani Z Pezeshki-Nejad M Almasi-Kashi Journal Article 2019 11 26 This paper demonstrates the results of the detailed studying of the magnetic behavior of Co2FeAl alloy nanoparticles synthesized through a co-precipitation method. First order reversal curves (FORCs) diagrams were used consequently. The obtained results showed that the prepared alloys consist of a mixture of the low-coercivity grains (Hc ~ 0), and interacting single-domain high-coercivity grains. Elongated FORC diagrams along Hc axis indicated a wide particle size distribution in the products. Spherical and uniform nanoparticles with a size distribution of 30-90nm were observed in the SEM and TEM images of the synthesized samples. Maximum values of Ms (about 91.5 emu/g), and coercivity (487 Oe) were obtained for the sample synthesized with the optimum annealing conditions up to 700 ̊C with 10 ̊C/min. This paper demonstrates the results of the detailed studying of the magnetic behavior of Co2FeAl alloy nanoparticles synthesized through a co-precipitation method. First order reversal curves (FORCs) diagrams were used consequently. The obtained results showed that the prepared alloys consist of a mixture of the low-coercivity grains (Hc ~ 0), and interacting single-domain high-coercivity grains. Elongated FORC diagrams along Hc axis indicated a wide particle size distribution in the products. Spherical and uniform nanoparticles with a size distribution of 30-90nm were observed in the SEM and TEM images of the synthesized samples. Maximum values of Ms (about 91.5 emu/g), and coercivity (487 Oe) were obtained for the sample synthesized with the optimum annealing conditions up to 700 ̊C with 10 ̊C/min. Heusler alloy Co2FeAl nanoparticles FORC analysis co-precipitation method
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Study of laser ablation using nano-second laser pulses Study of laser ablation using nano-second laser pulses 75 88 1416 10.29252/ijpr.19.1.9 FA S Namvar A R Ganjovi M A Bassam Journal Article 2019 11 26  In this paper, the laser ablation process based on the irradiation of nanosecond pulsed lasers on a copper target surface in the presence of Helium gas is studied. The dynamical behaviors of the generated plasma in the helium gas and evaporated copper at the atmospheric pressure are examined using a laser pulse, laser wavelength of and intensity of 7×1010W/cm2. A one-dimensional thermal model is used and, the numerical results show that, if the ionization and laser absorption processes in plasma plume are considered, the plume dynamics is strongly affected. It is seen that, the ionization at the copper surface will be increased during the laser pulses irradiation. On the other hand, the ionization degree for both the copper and helium is significantly varied according to their atomic structure. Moreover, for laser intensity in the range of 108 to 5×109W/cm2, the laser ablation is not occurred. The laser ablation threshold is about 5×109W/cm2. The first order ionization for copper is the dominant process in the proximity of both the target surface and mixed layer. On the other hand, in the plasma core, the second order ionization of copper is dominant. Besides, it is shown that, in the proximity of the target surface, the influences of photoionization and reverse Bremsstrahlung absorption for the electron-neutral are higher. In addition, the target parameters, including melt depth, evaporation depth and rate, plasma density, helium gas density, expansion velocity, plasma temperature and laser intensity reaching the copper target surface are studied.  In this paper, the laser ablation process based on the irradiation of nanosecond pulsed lasers on a copper target surface in the presence of Helium gas is studied. The dynamical behaviors of the generated plasma in the helium gas and evaporated copper at the atmospheric pressure are examined using a laser pulse, laser wavelength of and intensity of 7×1010W/cm2. A one-dimensional thermal model is used and, the numerical results show that, if the ionization and laser absorption processes in plasma plume are considered, the plume dynamics is strongly affected. It is seen that, the ionization at the copper surface will be increased during the laser pulses irradiation. On the other hand, the ionization degree for both the copper and helium is significantly varied according to their atomic structure. Moreover, for laser intensity in the range of 108 to 5×109W/cm2, the laser ablation is not occurred. The laser ablation threshold is about 5×109W/cm2. The first order ionization for copper is the dominant process in the proximity of both the target surface and mixed layer. On the other hand, in the plasma core, the second order ionization of copper is dominant. Besides, it is shown that, in the proximity of the target surface, the influences of photoionization and reverse Bremsstrahlung absorption for the electron-neutral are higher. In addition, the target parameters, including melt depth, evaporation depth and rate, plasma density, helium gas density, expansion velocity, plasma temperature and laser intensity reaching the copper target surface are studied. laser ablation plasma plume expansion- laser irradiance photoionization reverse Bremsstrahlung absorption
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Study of elastic and piezoelectric properties of two-dimensional hexagonal III-V binary compounds: First-principles calculations Study of elastic and piezoelectric properties of two-dimensional hexagonal III-V binary compounds: First-principles calculations 89 100 1417 10.29252/ijpr.19.1.10 FA S Norouzi N Shahtahmassebi M Behdani M Rezaee Roknabadi Journal Article 2019 11 26 In this work, using plane wave method in the framework of density-functional theory, we calculated clamped-ion and relaxed-ion elasticity, stress and strain piezoelectric independent coefficients for seven stable combinations of honeycomb monolayers XY (X:B,Al,Ga,In ; Y:N,P,As,Sb). The coefficients calculations by two methods of density functional perturbation theory (DFPT) and finite difference (FD) have been done with very good agreement. The results showed that seven combined BN, BP, BAs, BSb, AlN, GaN and InN have honeycomb structure and polarized, and because of the 3m point-group symmetry in this class of 2D materials only exhibit two  independent  elasticity coefficients and one independent stress or strain piezoelectric coefficient. Among the seven combinations, the highest relaxed-ion piezoelectric coefficients calculated for AlN(d11=3.05 pm/V) and InN (d11=7.01 pm/V) .The group of 2D polarized materials that exhibit simultaneously piezoelectric and semiconducting properties are good candidates for use in the new branch of nanotechnology called nanopiezotronics. In this work, using plane wave method in the framework of density-functional theory, we calculated clamped-ion and relaxed-ion elasticity, stress and strain piezoelectric independent coefficients for seven stable combinations of honeycomb monolayers XY (X:B,Al,Ga,In ; Y:N,P,As,Sb). The coefficients calculations by two methods of density functional perturbation theory (DFPT) and finite difference (FD) have been done with very good agreement. The results showed that seven combined BN, BP, BAs, BSb, AlN, GaN and InN have honeycomb structure and polarized, and because of the 3m point-group symmetry in this class of 2D materials only exhibit two  independent  elasticity coefficients and one independent stress or strain piezoelectric coefficient. Among the seven combinations, the highest relaxed-ion piezoelectric coefficients calculated for AlN(d11=3.05 pm/V) and InN (d11=7.01 pm/V) .The group of 2D polarized materials that exhibit simultaneously piezoelectric and semiconducting properties are good candidates for use in the new branch of nanotechnology called nanopiezotronics. piezoelectricity two-dimensional materials binary compounds III-V density functional perturbation theory
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 measuring viscoelastic properties of Red Blood Cell using optical tweezers measuring viscoelastic properties of Red Blood Cell using optical tweezers 101 108 1418 10.29252/ijpr.19.1.11 FA S N Seyed Reihani A Azadbakht E Mirzahossein M Mottaghian M Babaei Journal Article 2019 11 26 Efforts have been made to study the behavior of complex materials in micrometer dimensions with various techniques. One of these methods is the use of optical tweezers for biophysical applications. Red blood cells, as the most abundant blood-forming cells, play an important role in the life of living organisms, and their unique mechanical properties are important. In this report, the study of soft materials is done using light tweezers. This work investigates micrometer particle movements in the optical trap and also, when they are connected to a red blood cell. The tweezers allow the Newtonian fluid viscosity, such as water and glycerin, to measure the mechanical properties of viscoelastic materials, such as red blood cells.   Efforts have been made to study the behavior of complex materials in micrometer dimensions with various techniques. One of these methods is the use of optical tweezers for biophysical applications. Red blood cells, as the most abundant blood-forming cells, play an important role in the life of living organisms, and their unique mechanical properties are important. In this report, the study of soft materials is done using light tweezers. This work investigates micrometer particle movements in the optical trap and also, when they are connected to a red blood cell. The tweezers allow the Newtonian fluid viscosity, such as water and glycerin, to measure the mechanical properties of viscoelastic materials, such as red blood cells.   optical tweezers red blood cell cell microrheology viscoelasticity blood disease
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 The study of electronic conductance of a nanoribbon with square lattice including some impurities The study of electronic conductance of a nanoribbon with square lattice including some impurities 109 115 1419 10.29252/ijpr.19.1.12 FA M Jamshidi Farsani H Rabani 0000-0002-3327-2040 M Mardaani 0000-0002-6268-5311 Journal Article 2019 11 26 In this paper, we study the electronic conductance of a nanoribbon with square lattice by using Green’s function theory within the tight-binding approach. For this purpose, we separate the conductance modes in the ideal parts by using a suitable unitary transformation in order to obtain the analytic formula for the corresponding self-energies. Then, we present a fast computer algorithm based on the Fisher-Lee formula for the calculation of the system conductance. The results show that the distribution of electrical impurities with different on-site energies leads to the different values of the system electronic conductance and it is generally decreasing.   In this paper, we study the electronic conductance of a nanoribbon with square lattice by using Green’s function theory within the tight-binding approach. For this purpose, we separate the conductance modes in the ideal parts by using a suitable unitary transformation in order to obtain the analytic formula for the corresponding self-energies. Then, we present a fast computer algorithm based on the Fisher-Lee formula for the calculation of the system conductance. The results show that the distribution of electrical impurities with different on-site energies leads to the different values of the system electronic conductance and it is generally decreasing.   electronic conductance nanoribbon electrical impurity Green’s function
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Investigation of extinction spectra of THTS Mn thin films and comparsion with discrete dipole approximation simulation results Investigation of extinction spectra of THTS Mn thin films and comparsion with discrete dipole approximation simulation results 117 127 1420 10.29252/ijpr.19.1.13 FA M Fakharpour Journal Article 2019 11 26 In this work, the extinction spectra of the nano-structure of the Tilt Helical and Stair-like Towers of Mn thin films were obtained using discrete dipole approximation (DDA) simulation for both s-and p-polarization at two incident light angles of 10°, and 60° at different azimuthal angles for the there samples with different tilt. Obtained results are compared with the experimental optical extinction spectra. The plasmonic peaks appeared at wavelength about 600 nm for both experimental measurments and theory calculations. The experimental spectra for some of the samples are changed in some of the azimuthal angles which are called spectral abnormal. These abnormals is due to the change of the tilt angle and increasing the shadowing effect in the structure of the film, which this may cause increasing the surface fraction of void and forming defects in the structure. However, in the simulation results are not observed these obnormals beacause the voids and defects in the structure becomes negligible and this is the most difference important in spectra obtained for both the experimental and theory results. In this work, the extinction spectra of the nano-structure of the Tilt Helical and Stair-like Towers of Mn thin films were obtained using discrete dipole approximation (DDA) simulation for both s-and p-polarization at two incident light angles of 10°, and 60° at different azimuthal angles for the there samples with different tilt. Obtained results are compared with the experimental optical extinction spectra. The plasmonic peaks appeared at wavelength about 600 nm for both experimental measurments and theory calculations. The experimental spectra for some of the samples are changed in some of the azimuthal angles which are called spectral abnormal. These abnormals is due to the change of the tilt angle and increasing the shadowing effect in the structure of the film, which this may cause increasing the surface fraction of void and forming defects in the structure. However, in the simulation results are not observed these obnormals beacause the voids and defects in the structure becomes negligible and this is the most difference important in spectra obtained for both the experimental and theory results. nano-structure of the Tilt Helical and Stair-like Towers Discrete Dipole Approximation extinction spectra
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Comparison of the effect of Si and Ge presence on phase formation process, the structural and magnetic properties of Co2FeX (X=Ge,Si) Heusler compounds Comparison of the effect of Si and Ge presence on phase formation process, the structural and magnetic properties of Co2FeX (X=Ge,Si) Heusler compounds 129 137 1421 10.29252/ijpr.19.1.14 FA M Safari 0000-0002-9300-0143 M Hakimi Journal Article 2019 11 26 In this study, the Co2FeX (X=Ge, Si) Heusler compounds with 30 valence electrons, which are made by using mechanical alloying and arc melting methods were studied. The crystallization of samples was confirmed by XRD data in both manufacturing methods. The results showed that the presence of Si than Ge in the compound played a more effective role to creation a large scale atomic ordering, and the maximum saturation magnetization is related to one of the Co2FeSi samples equal to 5.24 . However, the amount obtained is still less than the predicted value by the Slater-Pauling due to this fact that the sample isn’t single crystalline. The microstructure analysis showed that Ge has been working more effective than Si on the enhancement of crystalline nucleation in the milling process. Although the crystallite growth in the annealing process is more rapid in the presence of Ge due to the lower melting point of Ge than Si. The great coercivity observed in the milled sample of Co2FeSi compound was related to the significant anisotropy caused by the atomic ordering and also the large volume of crystallite boundary as barriers into wall movement of domains. In this study, the Co2FeX (X=Ge, Si) Heusler compounds with 30 valence electrons, which are made by using mechanical alloying and arc melting methods were studied. The crystallization of samples was confirmed by XRD data in both manufacturing methods. The results showed that the presence of Si than Ge in the compound played a more effective role to creation a large scale atomic ordering, and the maximum saturation magnetization is related to one of the Co2FeSi samples equal to 5.24 . However, the amount obtained is still less than the predicted value by the Slater-Pauling due to this fact that the sample isn’t single crystalline. The microstructure analysis showed that Ge has been working more effective than Si on the enhancement of crystalline nucleation in the milling process. Although the crystallite growth in the annealing process is more rapid in the presence of Ge due to the lower melting point of Ge than Si. The great coercivity observed in the milled sample of Co2FeSi compound was related to the significant anisotropy caused by the atomic ordering and also the large volume of crystallite boundary as barriers into wall movement of domains. Heusler alloys magnetism half metal Milling coercivity mechanical alloying Arc melting
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Improving the performance of cadmium telluride solar cell (CdTe) with different buffer layers Improving the performance of cadmium telluride solar cell (CdTe) with different buffer layers 139 147 1422 10.29252/ijpr.19.1.15 FA M Danaie S Khani E Noorozzadeh M Vahdani Journal Article 2019 11 26 In this paper, the performance of the buffer layer of Cadmium Telluride (CdTe) thin film solar cell was optimized using SCAPS software. At first, five different buffer layers including CdS, In2S3, ZnO, ZnSe and ZnS with variable thicknesses from 10 to 100 nm have been replaced in the structure of the solar cell and it has been observed. As the thickness of the buffer layer is increased, the efficiency decreases.Due to the increase of thickness light absorption in the structure is increased and less light is absobed in CdTe layer. The reason behinf this incident is described physically. Then the performance of the solar cell with different buffer layers is compared, and the effect of each of the layers on the four main parameters of the solar cell has been investigated. Simulation results show that the ZnS buffer layer has a higher efficiency in all thicknesses than other materials which originates from the fact that the bandgap of this material is bigger than other materials. In this paper, the performance of the buffer layer of Cadmium Telluride (CdTe) thin film solar cell was optimized using SCAPS software. At first, five different buffer layers including CdS, In2S3, ZnO, ZnSe and ZnS with variable thicknesses from 10 to 100 nm have been replaced in the structure of the solar cell and it has been observed. As the thickness of the buffer layer is increased, the efficiency decreases.Due to the increase of thickness light absorption in the structure is increased and less light is absobed in CdTe layer. The reason behinf this incident is described physically. Then the performance of the solar cell with different buffer layers is compared, and the effect of each of the layers on the four main parameters of the solar cell has been investigated. Simulation results show that the ZnS buffer layer has a higher efficiency in all thicknesses than other materials which originates from the fact that the bandgap of this material is bigger than other materials. solar cell thin film Buffer layer band gap absorbing layer
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Study of non-linear interaction of circular laser pulse propagating through hot magnetized plasma in the presence of a planar magnetostatic wiggler Study of non-linear interaction of circular laser pulse propagating through hot magnetized plasma in the presence of a planar magnetostatic wiggler 149 155 1423 10.29252/ijpr.19.1.16 FA M Abedi-Varaki S Jafari Journal Article 2019 11 26 In this paper, the self-focusing property of an intense circularly polarized laser pulse in hot magnetized plasma is investigated theoretically. First, an envelope equation governing the spot-size of the laser beam for both left- and right-hand polarizations has been derived in the presence of a planar wiggler. Furthermore, non-linear dispersion relation of laser pulse is obtained by using Maxwell’s equations and relativistic fluid momentum equation. The numerical results show that with increasing the wiggler field, strength self-focusing of the right-hand polarization laser pulse is enhanced, while for the left-hand polarization, laser de-focusing is enhanced. In addition, it is shown that with increasing the wiggler frequency, the normalized laser power has an enhancing behavior. Besides, it is found that effect of the wiggler field on the density profile in the right-hand polarization is more prominent. In this paper, the self-focusing property of an intense circularly polarized laser pulse in hot magnetized plasma is investigated theoretically. First, an envelope equation governing the spot-size of the laser beam for both left- and right-hand polarizations has been derived in the presence of a planar wiggler. Furthermore, non-linear dispersion relation of laser pulse is obtained by using Maxwell’s equations and relativistic fluid momentum equation. The numerical results show that with increasing the wiggler field, strength self-focusing of the right-hand polarization laser pulse is enhanced, while for the left-hand polarization, laser de-focusing is enhanced. In addition, it is shown that with increasing the wiggler frequency, the normalized laser power has an enhancing behavior. Besides, it is found that effect of the wiggler field on the density profile in the right-hand polarization is more prominent. self-focusing planar magnetostatic wiggler laser spot-size hot magnetized plasma
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Fluid description of collisional current filamentation instability of a weakly ionized plasma in the presence of magnetic field Fluid description of collisional current filamentation instability of a weakly ionized plasma in the presence of magnetic field 157 166 1424 10.29252/ijpr.19.1.17 FA K Hajisharifi S Tajik-Nezhad H Mehdian Journal Article 2019 11 26 In this paper, the collisional filamentation instability of an electron beam-weakly magnetized and ionized plasma has been investigated in the presence of background plasma, using the fluid description. By describing the equilibrium configuration in the presence of binary collision terms between charged and neutral particles and using the local approximation method, the dispersion relation (DR) of instable mode (filamentation instability) has been obtained and the effect of collision and magnetic field driven-destabilization and current-driven stabilization on the growth rate of instability has been studied. The results show the cut-off wave number and the magnetic threshold for the filamentation instability in the collisional magnetized plasma in which the instability will disappear for the larger wave number and larger magnetic fields. Studies show that the value of cut-off wave number and magnetic threshold are raised by increasing the electron beam current density.   In this paper, the collisional filamentation instability of an electron beam-weakly magnetized and ionized plasma has been investigated in the presence of background plasma, using the fluid description. By describing the equilibrium configuration in the presence of binary collision terms between charged and neutral particles and using the local approximation method, the dispersion relation (DR) of instable mode (filamentation instability) has been obtained and the effect of collision and magnetic field driven-destabilization and current-driven stabilization on the growth rate of instability has been studied. The results show the cut-off wave number and the magnetic threshold for the filamentation instability in the collisional magnetized plasma in which the instability will disappear for the larger wave number and larger magnetic fields. Studies show that the value of cut-off wave number and magnetic threshold are raised by increasing the electron beam current density.   current filamentation instability wealky ionized plasma magnetic field fluid equations collision
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Investigation of Λ*)1405) resonant formation by using the energy spectrum of triton in stopped kaon absorption on 4He Investigation of Λ*)1405) resonant formation by using the energy spectrum of triton in stopped kaon absorption on 4He 167 176 1425 10.29252/ijpr.19.1.18 FA J Esmaili N Yahyaei Journal Article 2019 11 26 To determine the position of  quasi-bound state, the triton kinetic energy spectrum in the resonant capture of  at rest in  is calculated by a coupled-channel procedure. An  analysis of theoretical spectra to experimental data yielded the mass and width of , respectively, and, where a possible population of and a small p-orbit capture contribution are taken into account. The calculations show that by the variation of  potential parameters (range parameter, , and strength parameter,), the mass and width of  are almost independent of the potential parameters. To determine the position of  quasi-bound state, the triton kinetic energy spectrum in the resonant capture of  at rest in  is calculated by a coupled-channel procedure. An  analysis of theoretical spectra to experimental data yielded the mass and width of , respectively, and, where a possible population of and a small p-orbit capture contribution are taken into account. The calculations show that by the variation of  potential parameters (range parameter, , and strength parameter,), the mass and width of  are almost independent of the potential parameters. Λ*(1405) stopped kaon and interaction KN - Ʃπ
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Design, construction and calibration of single channel sun-photometer for study of aerosols Design, construction and calibration of single channel sun-photometer for study of aerosols 177 183 1426 10.29252/ijpr.19.1.19 FA M Imani A Bayat A Daroudi Journal Article 2019 11 26 Aerosols are tiny liquid or solid particles suspended in the air have a strong influence on air quality, human health and climate change. Sun-photometer is a tool for measuring the optical and physical characteristics of aerosols by using sunlight at various wavelengths from the Earth surface. In this paper, the design, construction, and calibration of a single channel sun-photometer is presented. Aerosols optical depth is amount of suspended particles in the Earth atmosphere was measured by the sun-photometer on September 5, 2016, and the results are in good agreement with the measurements of a CE 318-2 sun-photometer manufactured by the French CIMEL company. Aerosols are tiny liquid or solid particles suspended in the air have a strong influence on air quality, human health and climate change. Sun-photometer is a tool for measuring the optical and physical characteristics of aerosols by using sunlight at various wavelengths from the Earth surface. In this paper, the design, construction, and calibration of a single channel sun-photometer is presented. Aerosols optical depth is amount of suspended particles in the Earth atmosphere was measured by the sun-photometer on September 5, 2016, and the results are in good agreement with the measurements of a CE 318-2 sun-photometer manufactured by the French CIMEL company. Sun-photometer Aerosols Remote sensing Aerosol optical depth
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Modeling the evolution of cells outgrowth due to the force exerted by actins Modeling the evolution of cells outgrowth due to the force exerted by actins 185 195 1427 10.29252/ijpr.19.1.20 FA A Atakhani F Mohammad Rafiee A Gholami Journal Article 2019 11 26 Motility and membrane deformation are crucial to motile cells. Therefore formation of protrusion in the membrane has been the subject of various studies. The stable shape of the membrane and also its movements are controlled by the forces exerted by actin filaments. In order to study the protrusion behavior, we represented a toy model based on actin filaments polar characteristic and elastic characteristic of the membrane. We also studied the effect of changing physical parameters such as filament density, the membrane tension, and the polymerization rate on the shape and the magnitude of the protrusion. Motility and membrane deformation are crucial to motile cells. Therefore formation of protrusion in the membrane has been the subject of various studies. The stable shape of the membrane and also its movements are controlled by the forces exerted by actin filaments. In order to study the protrusion behavior, we represented a toy model based on actin filaments polar characteristic and elastic characteristic of the membrane. We also studied the effect of changing physical parameters such as filament density, the membrane tension, and the polymerization rate on the shape and the magnitude of the protrusion. protrusion membrane deformation actin filament semi-flexible region gel
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 A numerical study of droplet deformation in a flat funnelform microchannel A numerical study of droplet deformation in a flat funnelform microchannel 197 205 1428 10.29252/ijpr.19.1.21 FA E Kadivar 0000-0002-4923-9624 Journal Article 2019 11 26 Motivated by recent reported experiments, droplet deformation in a flat funnelform diverging microfluidic channel has been numerically studied. The structure of our microchannel is composed of two consecutive elements including a straight channel and a diverging channel. In this work, instead of solving the 3D Stokes equation, we solve a depth-averaged problem which is labeled two-dimensional problem. Employing the boundary element method (BEM), we numerically solve the Darcy equation in the two-dimensional and investigate droplet motion and droplet deformation as the droplet enters the flat funnelform diverging channel. Numerical simulations indicate that when a deformable droplet approaches the intersection of straight channel and funnelform diverging channel, the droplet decelerates and deforms. We numerically find that maximum deformation of droplet depends on droplet size, capillary number, and channel geometry. Our numerical scaling is in good agreement with the experimental scaling reports. Motivated by recent reported experiments, droplet deformation in a flat funnelform diverging microfluidic channel has been numerically studied. The structure of our microchannel is composed of two consecutive elements including a straight channel and a diverging channel. In this work, instead of solving the 3D Stokes equation, we solve a depth-averaged problem which is labeled two-dimensional problem. Employing the boundary element method (BEM), we numerically solve the Darcy equation in the two-dimensional and investigate droplet motion and droplet deformation as the droplet enters the flat funnelform diverging channel. Numerical simulations indicate that when a deformable droplet approaches the intersection of straight channel and funnelform diverging channel, the droplet decelerates and deforms. We numerically find that maximum deformation of droplet depends on droplet size, capillary number, and channel geometry. Our numerical scaling is in good agreement with the experimental scaling reports. funnel form microfluidic droplet deformation two-phase system boundary element method darcy equation
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Investigation of isomorph-invariance in liquid methane by molecular dynamics simulation Investigation of isomorph-invariance in liquid methane by molecular dynamics simulation 207 212 1429 10.29252/ijpr.19.1.22 FA L Separdar S Davatolhagh Journal Article 2019 11 26 In this paper, isomorph invariance of liquid methane is investigated by means of constant-NVT molecular dynamics simulations. According to the data extracted from simulations, equilibrium fluctuations show strong correlation between potential energy U and virial W. We also generated isomorph state points and investigated invariance of certain thermodynamic, structural, and dynamical properties. The result show methane is a strongly correlated liquid for temperatures at and above 300K such that the specific heat, radial disturbution function, and diffusion are invariant for state points generated along an isomorph curve when expressed in reduced units. Hence by knowing these properties at one state point, they can be obtained for other isomorphic state points by simple rescaling. In this paper, isomorph invariance of liquid methane is investigated by means of constant-NVT molecular dynamics simulations. According to the data extracted from simulations, equilibrium fluctuations show strong correlation between potential energy U and virial W. We also generated isomorph state points and investigated invariance of certain thermodynamic, structural, and dynamical properties. The result show methane is a strongly correlated liquid for temperatures at and above 300K such that the specific heat, radial disturbution function, and diffusion are invariant for state points generated along an isomorph curve when expressed in reduced units. Hence by knowing these properties at one state point, they can be obtained for other isomorphic state points by simple rescaling. Isomorph invariance Liquid methane molecular dynamics simulation
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Stable states in the radiant heat transfer of the near field for two parallel slabs Stable states in the radiant heat transfer of the near field for two parallel slabs 213 220 1430 10.29252/ijpr.19.1.23 FA S K Tavakoli M Nikbakht Journal Article 2019 11 26 In this paper, we study the dynamics of the radiative heat transfer of between two slabs. In these systems, depending on the type of slabs and the thermal interaction they have with their surroundings, they can have one or several stable states in the phase space. It can be seen that in these systems, quantities such as distance and thickness affect the states of these systems. We show that the distance between the slabs greatly affects the slabs reaching equilibrium. he Temperature of slabs in systems which has one equilibrium states, reach this state, regardless of the initial temperatures. However, systems with phase-change materials, could have several fixed points in their phase space. If the phase space of the system contains several fixed points, the final state of the system will be determined by the initial temperature of the slabs. In this paper, we study the dynamics of the radiative heat transfer of between two slabs. In these systems, depending on the type of slabs and the thermal interaction they have with their surroundings, they can have one or several stable states in the phase space. It can be seen that in these systems, quantities such as distance and thickness affect the states of these systems. We show that the distance between the slabs greatly affects the slabs reaching equilibrium. he Temperature of slabs in systems which has one equilibrium states, reach this state, regardless of the initial temperatures. However, systems with phase-change materials, could have several fixed points in their phase space. If the phase space of the system contains several fixed points, the final state of the system will be determined by the initial temperature of the slabs. radiation heat transfer bi-stability phase-change materials thermal memory
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Investigation of strong force influence on behavior of nuclear energy levels in Calcium and Titanium isotopes: Based on quantum chaos theory Investigation of strong force influence on behavior of nuclear energy levels in Calcium and Titanium isotopes: Based on quantum chaos theory 221 226 1431 10.29252/ijpr.19.1.24 FA S Behnia 0000-0001-6794-6560 V Razazi Journal Article 2019 11 26 The atomic nucleus is a complex many-body system that consists of two types of fermion (neutron and proton). They are in the strong interaction. The statistical properties of energy levels and influence of strong force between these fermions are well described by random matrix theory. Resonance of energy levels depends on the Hamiltonian symmetry placed in one of the GOE, GUE and GSE ensembles or in the integrable system in a Poissonian ensemble. We can study resonance of energy levels of one system with eigenvalues of the Hamiltonian. This paper by using the nuclear shell model investigate the influence of strong force on the nuclear structure in Calcium and Titanium isotopes with quantum chaos theory. Difference between these isotopes is in their Valance particles. Investigation the energy levels of them is show that behavior of the nuclear system in   Ti48 is very close to GOE ensemble but in Ca48 is a little bit far from this behavior The atomic nucleus is a complex many-body system that consists of two types of fermion (neutron and proton). They are in the strong interaction. The statistical properties of energy levels and influence of strong force between these fermions are well described by random matrix theory. Resonance of energy levels depends on the Hamiltonian symmetry placed in one of the GOE, GUE and GSE ensembles or in the integrable system in a Poissonian ensemble. We can study resonance of energy levels of one system with eigenvalues of the Hamiltonian. This paper by using the nuclear shell model investigate the influence of strong force on the nuclear structure in Calcium and Titanium isotopes with quantum chaos theory. Difference between these isotopes is in their Valance particles. Investigation the energy levels of them is show that behavior of the nuclear system in   Ti48 is very close to GOE ensemble but in Ca48 is a little bit far from this behavior Nuclear shell model Strong force Random matrix theory Quantum chaos theory
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Berry phase for a particle in an infinite spherical potential well with moving wall Berry phase for a particle in an infinite spherical potential well with moving wall 227 232 1432 10.29252/ijpr.19.1.25 FA R Moazzemi Journal Article 2019 11 26 In this paper we calculate the Berry phase for a wave function of a particle in an infinite spherical potential well with adiabatically varying. In order to do this, we need the solutions of the corresponding Schrödinger equation with a time dependent Hamiltonian. Here, we obtain these solutions for the first time. In addition, we calculate the Berry phase in one dimensional case for an infinite potential well. We see that this phase is comparable with the usual dynamical phase but with different sign. Therefore, it is important to take it into account in the quantum mechanical calculations. In this paper we calculate the Berry phase for a wave function of a particle in an infinite spherical potential well with adiabatically varying. In order to do this, we need the solutions of the corresponding Schrödinger equation with a time dependent Hamiltonian. Here, we obtain these solutions for the first time. In addition, we calculate the Berry phase in one dimensional case for an infinite potential well. We see that this phase is comparable with the usual dynamical phase but with different sign. Therefore, it is important to take it into account in the quantum mechanical calculations. Berry phase geometrical phase infinite spherical potential well
Isfahan University of Technology, The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 19 1 2019 11 26 Restricted charge recombination process in PbS quantum dot sensitized solar cells by different coating cycles of ZnS films Restricted charge recombination process in PbS quantum dot sensitized solar cells by different coating cycles of ZnS films 233 239 1433 10.29252/ijpr.19.1.26 FA M Mehrabian S Beygzadeh Journal Article 2019 11 26 The relatively low power conversion efficiency (PCE) of quantum dot sensitized solar cells (QDSSCs) is attributed to charge recombination at the interfaces. Charge recombination process could be suppressed by coating the QD layer with a wide band gap semiconductor such as ZnS, which acts as a blocking layer between the QDs and hole transport material (HTM). In present study, to improve PCE of PbS quantum dot sensitized solar cells, ZnS passivation layer has been successfully fabricated on PbS (QDs) by simple successive ion layer adsorption and reaction (SILAR) method at room temperature and ambient pressure. The effect of ZnS layer thickness on the photovoltaic properties was investigated by changing the coating cycles (n). Experimental results showed that ZnS passivation layer improved the photovoltaic performances of PbS QDSSCs by hindering the charge recombination process. The solar cell containing of ZnS layer with n=6 showed higher (short-circuit current density (Jsc), fill factor (FF) and PCE of 11.11mA.cm-2, 60.37% and 3.96%, respectively. By increasing the number of coating cycles to an optimum value of 6, the solar cell efficiency improved. We explored the reasons for this improvement and demonstrated that it is caused by a lower charge recombination of photo-injected electrons with the holes of HTM. The effect of coating cycles has been investigated by UV–Vis spectra and current density–voltage analysis. The relatively low power conversion efficiency (PCE) of quantum dot sensitized solar cells (QDSSCs) is attributed to charge recombination at the interfaces. Charge recombination process could be suppressed by coating the QD layer with a wide band gap semiconductor such as ZnS, which acts as a blocking layer between the QDs and hole transport material (HTM). In present study, to improve PCE of PbS quantum dot sensitized solar cells, ZnS passivation layer has been successfully fabricated on PbS (QDs) by simple successive ion layer adsorption and reaction (SILAR) method at room temperature and ambient pressure. The effect of ZnS layer thickness on the photovoltaic properties was investigated by changing the coating cycles (n). Experimental results showed that ZnS passivation layer improved the photovoltaic performances of PbS QDSSCs by hindering the charge recombination process. The solar cell containing of ZnS layer with n=6 showed higher (short-circuit current density (Jsc), fill factor (FF) and PCE of 11.11mA.cm-2, 60.37% and 3.96%, respectively. By increasing the number of coating cycles to an optimum value of 6, the solar cell efficiency improved. We explored the reasons for this improvement and demonstrated that it is caused by a lower charge recombination of photo-injected electrons with the holes of HTM. The effect of coating cycles has been investigated by UV–Vis spectra and current density–voltage analysis. ZnS passivation layer quantum dots charge recombination photovoltaic performance