Department of Atomic Molecular Physics (2008 - Present)
Physics
, Sharif University of Technology,
Physics
, Sharif University of Technology,
applied Physics
, Sharif University of Technology,
• First Name: Ahmad • Family Name: Moshaii • Date of Birth: August 23, 1974 • Place of Birth: Ghom, Iran. • Ph.D. in Physics, Experimental and theoretical study of a Sonoluminescing Bubble, Sharif University of Technology, Tehran, Iran 2004. • Master of Science, Auger electron spectroscopy of the oxide layer of Si (111) Sharif University of Technology, Tehran, Iran 1998. •Bachelor of Science, Sharif University of Technology, Tehran, Iran 1996.
Introduction Pressure ulcer (PU) is known as the third most costly disorder usually caused by prolonged pressure and stagnation in various parts of the body. Although several therapeutic approaches are employing, obstacles in appropriate healing for skin lesions still exist which necessitates new practical alternative or adjunctive treatments. Low level laser therapy (LLLT) as one of the mentioned new strategies have gained attention. Besides, curcumin is an herbal medicine extracted from turmeric with anti-inflammatory and antioxidative properties with promising beneficial therapeutic effects in wound healing. Employing dendrosomal nanoparticles, we overcome the hydrophobicity of curcumin in the present study. We hypothesized that combinat
A bimetallic nanostructure of Co/Cu for the non-enzymatic determination of glucose is presented. The heterostructure includes cobalt thin film on a porous array of Cu nanocolumns. Glancing angle deposition (GLAD) method was used to grow Cu nanocolumns directly on a fluorine-doped tin oxide (FTO) substrate. Then a thin film of cobalt was electrodeposited on the Cu nanostructures. Various characterization studies were performed in order to define the optimum nanostructure for the determination of glucose. The results showed remarkable boosting of the electrocatalytic activity of Co/Cu bimetallic structure compare to the responses achieved by the monometallic structures of Co or Cu. The sensor showed two linear response ranges for the determi
In this work, we have proposed a proper method to fabricate porous Cu nanostructured electrodes for non-enzymatic glucose detection. The glancing angle deposition (GLAD) has been used to produce Cu nanostructures on the FTO substrates. To optimize the sensing performance of the electrode, the effects of vapor deposition angle and azimuthal substrate rotation speed have been investigated. As a result, the superior electrocatalitic activity is obtained under the deposition angle of θ= 82 o and the substrate rotation speed of φ ̇= 20rpm, respectively. By controlling the GLAD deposition parameters, an excellent sensing performance against glucose with a high sensitivity of 1862μAcm-2 mM-1, a low detection limit of 0.048 μM and two wide lin
MethodsThree different sizes of gold nanoparticles were synthesized by citrate reduction method and after characterization, the nanoparticles were functionalized by Bcl-2 targeted DNAi. Cell internalization of the nanoparticles was analyzed by atomic absorption spectroscopy and light microscopy. The cytotoxic effects of the nanoparticles were investigated by MTT assay, flow cytometry and RT-PCR of the target gene.ResultsWhile poor cell internalization of bare gold nanoparticles was observed, the results demonstrated that cellular uptake of DNAi-conjugated gold nanoparticles is completely size-dependent, and the largest nanoparticle (~ 42 nm) revealed the highest internalization rate compared to other sizes (~ 14 and~ 26 nm). Experimental fi
A new approach has been developed to improve sensing performances of electrochemically grown Au nanostructures (AuNSs) based on the pre-seeding of the electrode. The pre-seeding modification is simply carried out by vacuum thermal deposition of 5 nm thin film of Au on the substrate followed by thermal annealing at 500 C. The electrochemical growth of AuNSs on the pre-seeded substrates leads to impressive electrochemical responses of the electrode owing to the seeding modification. The dependence of the morphology and the electrochemical properties of the AuNSs on various deposition potentials and times have been investigated. For the positive potentials, the pre-seeding leads to the growth of porous and hole-possess networks of AuNSs on the
Poly (triaryl amine) (PTAA) is one of the promising hole transport materials (HTM) for perovskite solar cells. Highly efficient PTAA-devices have been demonstrated in both direct (n-i-p) and inverted (p-i-n) architectures. In the inverted structures, the device suffers from poor coverage of the perovskite film over the hydrophobic PTAA surface. To address this issue, we exploited an easy and efficient approach utilizing a short-time UV treatment of the PTAA layer prior to the perovskite deposition. The UV-treatment improved the optical properties of PTAA layers, which synergistically helps the light harvesting of the perovskite. Enhanced grain sizes, together with the decrease of recombination centers in the UV treated dopant-free PTAA, lea
We have investigated the dependency of hysteresis in all-ambient-processed perovskite solar cells on the solvent used for the synthesization of perovskite. Methylammonium lead iodide (MAI) perovskite solar cells have been fabricated using the two-step sequential spin coating method. The influences of PbI2 precursor on the cell performance and its hysteresis are investigated using four different solvents of pure dimethylformamide (DMF), pure dimethyl sulfoxide (DMSO) and mixtures of DMF:DMSO with the ratios of (4:1) and (1:4). The results indicate that a small amount of DMSO in DMF leads to produce large grains of perovskite with proper coverages at the interfaces with hole and electron transport layers. The best conversion efficiency of 10
Vertically aligned Zinc Oxide nanowires (ZnO NWs) were grown on glass seeded substrates by the chemical bath deposition (CBD) method at a low temperature. Two parameters including temperature and atmosphere were varied while time and heating rate were kept constant. The field emission scanning electron microscopy images show that the ZnO NWs with a hexagonal cross section are grown perpendicular to the seeded glass substrates. The X-ray diffraction results reveal that all the ZnO NW arrays grow preferentially oriented along the c-axis in the direction of (002) plane with a hexagonal wurtzite structure. Photoluminescence measurements of the grown ZnO NWs on all samples exhibit a high ultraviolet (UV) peak intensity compared to a broad visibl
The diverse applications of gold nanoparticles (Au-NPs) with sizes less than 50nm require a comprehensive information about how to produce Au-NPs with different sizes and narrow size distributions for a desired application. In this work, a wide range of sizes of Au-NPs from 2.5 to 35nm has been synthesized by using two reducing agents of sodium citrate and sodium borohydride. We have studied the dependency of the size, polydispersity, surface potential, plasmonic spectrum, and pH of the resultant Au-NPs on the reducing agents' concentrations. The findings show that uniform and monodispersed Au-NPs can only be produced in specific ranges of concentrations of the reducing agents.
We have investigated the effect of deposition of a α-Fe2O3 thin layer on a substrate of TiO2 nanoparticles for photoelectrochemical (PEC) water splitting. The TiO2 layer was coated on an FTO substrate using the paste of TiO2 nanoparticles. The α-Fe2O3 layer was deposited on the TiO2 thin film, using the method of Successive Ionic Layer Adsorption and Reaction (SILAR) with different cycles. Various characterizations including XRD, EDX and FE-SEM confirm the formation of α-Fe2O3 and TiO2 nanoparticles on the electrode. The UV-visible absorption spectrum confirms a remarkable enhancement of the absorption of the α-Fe2O3/TiO2/FTO composite relative to the bare TiO2/FTO. In addition, the photocurrents of the composite samples are remarkably
A stable and sensitive non-enzymatic glucose sensor is proposed based on the hybrid thin films of copper on acetanilide/ITO-PET. The electrode was fabricated through a two-step synthesis process including electrochemical deposition of acetanilide on ITO-PET, subsequent by physical vapor deposition of a copper film. The electron microscopy images showed the formation of a porous structure on the ITO-PET sheet. Such modified electrode presents a high sensitivity of 59.95 μAmM− 1 cm− 2 with a low limit of detection of 1.501 μM. This glucose sensor exhibits a range of linear response between 2 to 12mM. In addition, it includes a variety of advantages as high flexibility, the possibility for scale-up production, low material consumption, l
In this paper we report on a notable improvement of the photoelectrochemical (PEC) properties of highly ordered Ag loaded TiO2 nanotube arrays (Ag/TNT). Electrochemical anodization and sequential chemical bath deposition with an optimum ratio of precursors were employed for the production of an Ag/TNT nanocomposite. X-ray diffraction analysis (XRD) and scanning electron microscopy SEM images indicate that the Ag nanoparticles were deposited completely on the surface of the pore wall of TiO2 nanotube arrays. The photoelectrochemical measurements, including LSV, chronoamperometry and EIS, indicate that the Ag/TNT sample with a ratio of 1 precursors exhibited the maximum photoelectrochemical efficiency with a photocurrent density of about 300
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