Asghar Asgari

• Professor
• Academic Staff at University of Tabriz

This study presents an analysis of a two-terminal tandem solar cell that integrates metal-doped, lead-free double ${{\rm Cs}_2}{{\rm AgBi}_{0.75}}{{\rm Sb}_{0.25}}{{\rm Br}_6}$ C s 2 A g B i 0.75 S b 0.25 B r 6 perovskite with silicon to enhance overall energy conversion efficiency. This study explores how the thicknesses of the top and bottom sub-...

This study presents an innovative approach to mitigate the cost of solar devices by employing luminescent solar concentrators (LSCs) that act as waveguides to direct sunlight toward photovoltaic (PV) cells. LSCs, while effective, face challenges such as escape cones and reabsorption losses during light concentration. To address these issues, we inv...

Metal halide perovskite light-emitting electrochemical cells (MHP-LECs) are promising due to their facile solution processability and exceptional optoelectrical properties. However, commercialization is hindered by poor thin-film coverage and the need for glovebox processing. This study addresses these issues by incorporating poly(ethylene oxide) (...

In this study, La1-xSrxCo0.2Fe0.8O3 (LSCF-x, x = 0.0, 0.2, 0.5, 0.8) perovskite oxides were synthesized as a supercapacitor electrode material using the combustion sol-gel method. A comprehensive analysis was conducted to examine the structural and electrochemical properties of LSCF-x. The partial substitution of Sr instead of La in the A site had...

Interdigitated heterojunction (IHJ) structures have recently been investigated as an alternatives to bulk heterojunction (BHJ) structures due to their better film morphology stability, reproducibility, and contact selectivity. Herein, the electrical and optical properties of a nonfullerene IHJ structure are investigated using drift diffusion and Ma...

Tandem solar cells owing to their layered structure in which each sub-cell utilizes a certain part of the solar spectrum with reduced thermal losses, are promising applicants to promote the power conversion efficiency beyond the Shockley–Queisser limit of single-junction solar cells. This study delves into the performance and optimization of 4-term...

Quantum dot light-emitting diodes (QLEDs) offer advantages including a wide color gamut, high color purity, high brightness, low turn-on voltage, and thin form for next-generation displays. This article used a unique metal oxide and polymer combination to develop a flexible QLED. CdSe/ZnS quantum dots are synthesized using the hot-injection method,...

In this study, Er3+-doped sulfophosphate glasses containing titanium nanoparticles (TiO2 NPs) with 0.0, 0.01, 0.02, 0.03, 0.04, and 0.05 mol% of silver (Ag) nanoparticles (AgNPs) were synthesized using the melt-quenching technique. The impact of AgNPs on the physical and structural characteristics, optical absorption and emission features, and phot...

Recent advancements in nanostructured photodetectors have led to the development of a new metamaterial absorber design that enables control of light absorption and prevents the loss of photons. An optical simulation studied a broadband plasmonic metamaterial absorber using two-dimensional MXene (Ti 3 C 2 T x ) with arrays of tetragram shapes. By al...

The combination of UV-ozone and Al-doping enhancements in the ZnO ETL layer was studied for fullerene-based (P3HT:PCBM) and nonfullerene-based (J71:m-ITIC) solar cells. The study focused on morphological and interfacial defects and their relation to the electrical and optical properties of different Al-doped ZnO layers. The study also investigated...

Herein, the infrared photodetection performance of the HgTe quantum dots embedded in a polymer matrix was studied using an FDTD solution. The role of P3HT polymer in the hybrid structure was investigated by focusing on optical enhancements. The simulation explored critical parameters such as photo absorption capabilities, electric field distributio...

Recently, ternary solar cells have developed as a vital photovoltaic-technology since they combine the advantages of both single junction and tandem solar cells with their processing simplicity, mechanical flexibility, and lightweight. In this paper, we have investigated the role of domain size and the weight ratio of fullerene and non-fullerene ac...

Semitransparent organic solar cells have become attractive recently because of their photon harvesting in the near-infrared and ultraviolet range and passing in the visible light region. Semitransparent organic solar cells with Glass/MoO3/Ag/MoO3/PBDB-T:ITIC/TiO2/Ag/PML/1DPCs structure have been studied in this work and the effects microcavity with...

One of the essential challenges of tandem solar cells is designing and adjusting the current-matched tandem structures with high efficiency and stability. Nitride-based wide band gap semiconductors, owing to their high stability and high resistance against the cosmic rays, are appropriate elements to apply as the top cell of tandem solar cells. On...

In this study, we perform a simulation analysis to investigate the influence of p-type and n-type doping concentration in BHJ SCs using the drift-diffusion model. Specifically, we investigate the effect of doping on the charge carrier transport and calculate the above-mentioned device parameters. We show that doping the active layer can increase th...

Semitransparent organic solar cells have become attractive recently because of their photon harvesting in the near-infrared and ultraviolet range and passing in the visible light region. Semitransparent organic solar cells with Glass/MoO 3 /Ag/MoO 3 /PBDB-T:ITIC/TiO 2 /Ag/PML/1DPCs structure have been studied in this work and the effects microcavit...

Semitransparent organic solar cells have become attractive recently because of their photon harvesting in the near-infrared and ultraviolet range and passing in the visible light region. Semitransparent organic solar cells with ITO/ZnO/PBDB-T:ITIC/MoO3/Ag/MoO3 structure have been studied in this work and the effects of PBDB-T:ITIC active layer thic...

In this article we introduce a magnetoplasmonics (MP) planar nanostructure with enhanced transverse magneto-optical (MO) activity. For this goal MO characteristics of magneto-structures containing both metal layer and linear array of (metal) nanorods are analyzed. We explore three types of structures with nanorods and compare their features based o...

This study develops a new approach for the synthesis of fluorescent N‐doped carbon quantum dots (CQDs), using cold atmospheric pressure plasma jet. Herein, the CQDs were synthesized with two plasma exposure times of 30 and 60 min. The UV‐Vis absorption spectrum confirms the existence of carbonic core and surface functional groups. The Fourier trans...

Semitransparent organic solar cells are attracted recently because they harvest photons in the near-infrared and ultraviolet range and pass in the visible light region. Semitransparent organic solar cells with ITO/ ZnO/ PBDB-T: ITIC/ MoO3/Ag/MoO3 structure have been studied in this work. The effects of active layer thicknesses and the transparent t...

Recently, ternary solar cells have developed as a vital photovoltaic-technology since they combine the advantages of both single junction and tandem solar cells with their processing simplicity, mechanical flexibility, and lightweight. In this paper, we have investigated the role of domain size and the weight ratio of fullerene and non-fullerene ac...

We consider a planar layered structure including a graphene sheet with an unexpected transmission of the beam in total internal reflection angles. In this paper, we investigate this particular response through the excitation of leaky type surface plasmons of graphene and the coupling of surface plasmons to far-field radiations. Dependence of the tr...

In this article we introduce a magnetoplasmonics (MP) planar nanostructure with enhanced transverse magneto-optical (MO) activity. For this goal MO characteristics of magneto-structures comprising both metal layer and linear array of (metal) nanorods are analyzed. We explore three types of structures with nanorods and compare their features based o...

In this paper, the performance of ridge-waveguide superluminescent light-emitting diodes (SLED) based on nitride quantum dots has been reported. For this purpose, the three-dimensional Schrodinger equation has been solved numerically by the finite volume method for truncated pyramidal quantum dots as active regions taking into account all spontaneo...

The temperature dependence of solar cells is a fundamental problem determines the device performance at unstable operating and environmental conditions. In this paper considering the temperature dependence of practical parameters, we have used an analytical drift-diffusion model to calculate the characteristic parameters of solar cell. We applied t...

In this work, we focus on the colloidal quantum dot based light-emitting diodes (QD-LEDs) performance. First, we synthesize the spherical QDs with a CdS core that covered with a wider band gap II–VI semiconductor acting as a shell (ZnS). In order to synthesize this nano crystal QDs with structure of CdS/ZnS/CdS/ZnS, we use a reverse micelle process...

In this paper, we have theoretically studied a poly (3-hexylthiophene): 6,6-phenyl C61-butyric acid methyl ester (P3HT: PCBM) organic solar cell with randomly dispersed bimetallic nanoparticles. We have considered bimetallic core–shell Ag–Au nanoparticles as scattering centers randomly distributed among the active layer of a P3HT: PCBM solar cell....

The quantum dot light-emitting diode (QLED) is a promising candidate for the display and lighting applications. Their fabrication process is very cost effective, using solution processing method. In this work, we tried to suggest suitable, and at the same time simple and low-cost colloidal quantum dot synthesis method to increase the efficiency of...

Journal of Research on Many-body Systems

In this work, time-resolved thermal lens and beam deflection methods were applied to determine the thermo-optical properties of Er3+ doped sulfophosphate glass in which different concentrations of Titanium dioxide (TiO2) nanoparticles (NPs) were embedded. Thermal diffusivity (D), thermal conductivity (k), and the temperature coefficient of the opti...

Semi-transparent luminescent solar concentrators window panels based on methylammonium lead bromide perovskite coatings are fabricated. It is shown that spraying as a large-scale fabrication technique delivers samples with comparable characteristics with those prepared by the physical vapor deposition or spin-coating methods. Three mirrorless, mirr...

In this work, we focus on the colloidal quantum dot based light-emitting diodes (QD-LEDs) performance. First, we synthesize the spherical QDs with a CdS core that covered with a wider band gap II–VI semiconductor acting as a shell (ZnS). In order to synthesize this nano crystal QDs with structure of CdS/ZnS/CdS/ZnS, we use a reverse micelle process...

In this work, the glass system with composition of (59-x)P2O5–20MgO–20ZnSO4–1Er2O3-xTiO2 (where 0≤x≤0.6 mol%) was prepared using melt-quenching method. The impact of varying titania nanoparticles (TNPs) concentration on the luminescence and self-cleaning properties of the glass system was studied. XRD pattern of prepared glass systems confirmed the...

In this study, the authors have theoretically investigated the effects of metallic nanoparticles (NPs) on the performance of nanowire‐based plasmonic photodetectors. For this goal, they propose a novel structure for plasmonic photodetectors in which the metallic NPs are deposited on a semiconductor nanowire sandwiched between two ohmic contacts. To...

The role of varied CaO concentration (as modifier) on the visible light emission traits of dysprosium ions (Dy³⁺) doped in sulfophosphate glasses was evaluated. These glasses were prepared and spectroscopic features of synthesized glasses were characterized. The amorphous nature of these glasses was studied by X-ray diffraction method. The Ultravio...

Research in the field of solar cells is generally based on balancing the trade-off between high absorption in thicker and efficient carrier extraction in thinner samples. Nanoparticle-assisted forward-scattering of the sunlight results in an artificial thickness increase for the absorption while keeping the carrier extraction thickness at its initi...

In this paper, we present numerical calculation to study the effect of temperature on lifetime of laser levels, optical gain and output power in an unintentionally doped AlGaN/GaN quantum cascade laser. In the calculations, we have included the effects of internal polarization fields, and different scattering mechanisms using self-consistent numeri...

The conventional melt quenching method was used to synthesis erbium and samarium ions co-doped sulfophosphate glasses containing TiO2 nanoparticles with the molar compositions of (58.0-x)P2O5-20.0MgO-20.0ZnSO4-1.0Sm2O3-1.0Er2O3-xTiO2 with x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 mol%. The X-ray diffraction (XRD) technique was applied to verify that the...

This study reports the impact of silver (Ag)/titania (TiO2) nanoparticles (TNPs) on optical and photocatalytic features of samarium ions (Sm³⁺) doped sulfophosphate glass system. Sulfophosphate glasses with the molar composition of (58.5-x) P2O5-20.0MgO-20.0ZnSO4-1.0Sm2O3-0.5Ag-xTiO2 with x = 0.0, 0.1, 0.2, 0.3 and 0.4 mol% were synthesized. Densit...

This paper introduces a novel lateral quantum well solar cell, and investigates the effects of structural parameters of these nanostructures on the device’s performance. For modeling the device, first, the absorption coefficients and the reflectance parameters of the device at different regions were calculated. Those parameters were then used to fi...

In this paper, the performance of bulk heterojunction (BHJ) organic solar cells (OSCs) in the presence of random dispersed Ag nanoparticles (NPs) into the active layer is investigated. By the well-known Maxwell-Garnett effective medium theory, we have analyzed the optical absorption of P3HT:PCBM and PCDTBT:PCBM photoactive blends when spherical Ag...

In describing the charge carriers’ separation mechanism in the organic solar cell, providing a method, which considers the impact of all parameters of interest on the same footing within an inexpensive numerical effort, could play an essential role. We use here a simple tight-binding model to describe the dissociation of the charge carriers and inv...

Graphene is a two-dimensional layer of carbon atoms in a honeycomb lattice which has outstanding optical and electrical characteristics. Ability of graphene in supporting surface plasmon polariton (SPP) waves in the THz and infrared ranges results to attract considerable attention in recent decade. In the graphene-Otto configuration (GOC), a TM pol...

In this paper, the structured parameters effect on nonlinear optical properties of CdS/ZnS quantum dot (QD)is studied. The self-consistently solved Schrodinger–Poisson equations obtains the QDs energy eigen values and functions. Then, size effect of QDs on energy levels of the ground and first excited states, matrix element and third-order nonlinea...

Sm³⁺-doped zinc magnesium sulfophosphate glasses were synthesized by conventional melt-quench technique. FTIR spectra were recorded to investigate the structural properties of the glasses. Differential thermal analysis (DTA) was confirmed the thermal stability of studied glass samples. UV–Vis-NIR absorption spectroscopy was obtained and J-O analysi...

A brief survey on the motivation and urges of photovoltaic solar energy as well as its basic concepts and working principles. Including a short discussion on the superiority of the Perovskite solar cells followed by presenting our published model for the grain size effects in the perovskite solar cells.

Full Automatic Portable Solar Cooker with the ability to convert visible light into infrared

We display that the process of charge carriers’ separation at molecular photocells is a complex phenomenon that is controlled by the cumulative action of Coulomb interaction for electron-hole pairs and LUMO-LUMO offset energies. By applying quantum scattering theory and the Lippmann-Schwinger equation, we provide a comprehensive framework of the de...

In this paper, we propose a quantum dot (QD) based white light emitting diode (WLED) structure to study theoretically the material gain and quantum efficiency of the system. We consider the spherical QDs with a II–VI semiconductor core (CdS) that covered with a wider band gap semiconductor acting as a shell (ZnS). In order to generate white light s...

A theoretical approach based on the Matthiessen rule for scattering lifetime is presented to formulate the effective characteristics of polycrystalline solar cells. Application of this method to Perovskite solar cells obtains polycrystalline bulk defect density for diverse grain sizes along with the determination of surface recombination velocity a...

Graphene is an outstanding photoconductive material for photodetection because of its wide range absorption spectrum and ultrafast response. It is well understood that by adding metal nanoparticle clusters on graphene layer enhances the absorption, also makes possible to focus on a particular region of the optical spectra via subwavelength plasmoni...

Quantum dot base infrared detectors have many advantages such as lower dark current, higher operating temperature, higher photoconductive gain, and broader infrared response. For this reason, we have studied a pyramidal shape quantum-dot infrared photodetector (QDIP) in which the different mechanisms of noise and dark current, the effects of QD siz...

High efficient coupling of graphene surface plasmons to far field radiation is possible by some techniques and can be used in the radiating applications. Besides of the coupling efficiency, the angular distribution of the radiated power is an important parameter in the radiating devices performance. In this paper we investigate the gain of the far...

: Graphene surface plasmon polaritons are electromagnetic excitations propagating at the graphene surface and evanescently confined in the perpendicular direction. Coupling of these modes into the far field radiation is possible via a high refractive index medium near the graphene. Such layered structures are capable to support the leaky surface pl...

FLG/SiQDs/Si heterojunction solar cells consisting of a layer of silicon quantum dots (SiQDs) sandwiched between few-layer graphene (FLG) and p- or n-type silicon is examined by a device physics model incorporated with the optical characteristics of FLG and SiQDs. FLG/SiQDs/Si solar cells enhance short-circuit current density, because charge carrie...

In this paper, the dispersion equation for TM polarized surface plasmon modes in the graphene layer embedded in a layered structure has been derived and numerically solved in THz frequencies (0.5–10 meV). Our model results show that this configuration, depending on the frequency region, can support both bound and leaky surface plasmons. Investigati...

The tunability of propagation properties of surface plasmon polariton (SPP) modes in a waveguide formed by two parallel graphene layers separated by a dielectric layer is studied. For this purpose, the dispersion equation of the structure is numerically solved and the effects of applied bias voltage, the role of effective structural parameters, and...

Solid-state supercapacitors are fabricated using transparent polymethyl methacrylate (PMMA) films decorated by breath figures BF, as an electrode and polyvinyl alcohol (PVA)-H2SO4 as an electrolyte. The holes on the surface of the transparent PMMA created by BF method have diameters of 0.5–10 μm. Graphene is deposited by spray coating using a dispe...

In this paper, a scaling study of heterojunction solar cells based on p-type silicon quantum wires with rectangular cross sections in the sub-10-nm regime and graphene (p-SiQWs/G) is presented. The scaling issues in p-SiQWs/G solar cells performance focusing on SiQWs diameter, the distance between SiQWs, and the number of graphene layers is investi...

In the present work, we theoretically study the possibility of luminescence emission from two systems of nonpolar Al0.3Ga0.7N/GaN Core-shell and core-multi-shell c-axis oriented nanowires with hexagonal cross section. To obtain energy levels and wave functions through the solution of Schrodinger-Poisson equations, numerical Self-consistent procedur...

A theoretical approach based on Drift-Diffusion equations is presented to study planar mixed lead halide perovskite solar cells. Updated physical parameters such as permittivity, mobility, effective density of states and doping density is employed in simulations. Current-voltage curve data for two experimental sample is imported and through fitting...

In this study, the effects of GaN capping layer on the behaviour of AlGaN/GaN nanostructure based laser is considered. We have employed the self-consistent solution of Poisson and Schrodinger equations for calculation of the energy levels, wave functions and conduction and valance bands profile. The impact of different thicknesses of the capping la...

Using an ideal model for quantum well solar cells, a theoretical work is done to explore the dependence of terminal characteristics of Al0.56Ga0.44As solar cell to quantum well properties. Two systems of constant and variable width multi quantum wells (VWMQW) are considered in the study. Open-circuit voltages, short-circuit current densities, and c...

In this work, a numerical approach to investigate the room temperature luminescence emission from core/shell nanowire is presented where GaN quantum discs (QDiscs), periodically distributed in AlxGa1-xN nanowire, is considered as core and AlxGa1-xN as shell. Thin disk shaped (Ring shaped) n-doped region has been placed at the GaN/ AlxGa1-xN (AlxGa1...

In this work, a numerical approach to investigate the room temperature luminescence emission from core/shell nanowire is presented where GaN quantum discs (QDiscs), periodically distributed in AlxGa1-xN nanowire, is considered as core and AlxGa1-xN as shell. Thin disk shaped (Ring shaped) n-doped region has been placed at the GaN/ AlxGa1-xN (AlxGa1...

We discuss the effects of charge carrier interaction and recombination on the operation of molecular photocells. Molecular photocells are devices where the energy conversion process takes place in a single molecular donor-acceptor complex attached to electrodes. Our investigation is based on the quantum scattering theory, in particular on the Lippm...

We present a quantum formalism that provides a quantitative picture of the fundamental processes of charge separation that follow an absorption event. We apply the formalism to two-level photovoltaic cells and our purpose is to pedagogically explain the main aspects of the model. The formalism is developed in the energy domain and provides detailed...

Random plasmonic nanostructures are very suitable candidates for light trapping in thin film solar cells because of their ability of efficient transportation and localization of light in a broad spectrum. In this work, besides the introducing of a novel structure of plasmonic thin-film solar cell, in which metal nanoparticles are randomly distribut...

In this paper, a novel lateral quantum well solar cell has been introduced, and the structural parameters effects of these nano-structures on the performance of the device have been investigated. For modeling, the continuity equation has been solved in the quasi neutral regions. However, to analyze the quantum wells' effects, first the Schrodinger...

In this paper, the effects of random Ag nanoparticle used within the active layer of Si based thin film solar cell are investigated. To avoid the complexity of taking into account all random nanoparticles, an effective dielectric function for random Ag nanoparticles and Si nanocomposites is used that is the Maxwell-Garnet theory along with Percus-Y...

We present a novel simple model to describe molecular photocells where the energy conversion process takes place by a single molecular donor-acceptor complex attached to electrodes. By applying quantum scattering theory, an open quantum system method, the coherent molecular photocell is described by a wave function. We analyze photon absorption, en...

Bulk heterojunction (BHJ) organic photovoltaic cells are analysed within a simple efficient model that includes the important physical properties of such photovoltaic systems. In this model, in contrast with most of the previous studies, we take into account the motion of both the electron and the hole in the separation process at the donor-accepto...

The present paper reports the effects of nonlinear optical gain and thermal carrier escape on light-current characteristics in self-assembled quantum dot (QD) lasers based on a rate equation model. Comparison of the obtained simulated results with empirical findings showed that it is necessary to consider the effects of thermal carrier escape and n...

Recently, nitride based semiconductors have become attractive as high-efficiency electro-optic devices, due to their direct transition, wide bang-gap and high thermal stability. This paper intends to theoretically study the external quantum efficiency of homo-multijunction GaN solar cells by considering the effect of temperature on electron and hol...

The effect of the silver nanoparticle size on the performance of plasmonic Si thin-film solar cells with randomly distributed Ag nanoparticles,is studied. İn order to acheive the maximum short current density, we have investigated the role of size anf filling fraction of nanoparticles. İt has been found that there is an optimum situation that th...

Using the spectral density representation, we have investigated thye effective dielectric function of random distributed Ag nanoparticles in Silicon host. İn this way we have used two well-known theories for calculating the effective dielectric function such as: Maxwell-Garnett and bruggeman theories. The results of bruggeman theory for high val...

Following letter introduces a theoretical approach to investigate the effect of two-step GaN barrier layer growth methodology on the performance of InGaN/GaN MQW solar cell, in which a lower temperature GaN cap layer was grown on top of each quantum well followed by a higher temperature GaN barrier layer. Different growth conditions would cause cha...

The purpose of this paper is to introduce an appropriate effective dielectric function for a system, composed of randomly distributed spherical metal nanoparticles in a dielectric medium. For the dielectric function of a single metal nanoparticle we have used both Drude and Drude-Lorentz Models and compared the results. It has been found that effec...

In this study, a theoretical model is used to simulate the lasing characteristics of InGaAs/GaAs self-assembled quantum dot lasers. The rate equation for InGaAs/GaAs is numerically solved using the fourth-order Runge–Kutta method. We consider the homogeneous and inhomogeneous broadening of the optical gain, both with and without considering the non...