فصلنامه نانو مقیاس
سال یازدهم شماره 1 (پیاپی 41، بهار 1403)

Due to the unique physical and chemical properties of two-dimensional (2D) materials, such as linear band structure near the Fermi level, high electrical and thermal conductivity, they have opened up a wide vision in the fabrication of nanoelectronic devices, energy storage and information transmission. One of the theses materials that has recently received attention is a two-dimensional monolayer of boron atoms called borophene which has various allotropes such as α, β12, χ3, 2-pmmn and 8-pmmn. This 2D material has tilted and anisotropic Dirac cone and in addition to excellent transparency, it has excellent electron and ion conductivity. These properties along with other properties of borophene have caused diverse and potential applications of this material in gas sensors, metal ion batteries and electronic and optoelectronic devices. In this paper, we intend to review the properties of borophene and investigate the effect of factors such as impurity, light radiation, strain, dimension reduction in the form of nanoribbon, temperature, electric and magnetic fields on the properties of electron transport in this material.

Access to cheap and suitable large-scale techniques is crucial for the fabrication of efficient perovskite planar solar cells. Today, the commonly used spin-coating laboratory process for large-scale fabrication of composite perovskite layers faces challenges. In this paper, tri-cationic perovskite layers with formadinium (FA) have been synthesized using electrochemical deposition (ELD) as a novel and scalable approach, then the result was compared with the anti-solvent process based on spin coating (SCA). Compared to conventional SCA perovskite, current-voltage results show a significant increase in fill factor (FF) from 53.97% to 60.79% due to reduced recombination paths without sacrificing open-circuit voltage (VOC) and short-circuit current (JSC).

The use of photothermal effect is an appropriate method for generating solar steam without the use of fossil fuels. In this study, a graphene aerogel/Cu2S nanoflower composite was prepared and used for rapid water evaporation. The Cu2S nanoflowers were synthesized using a solvothermal method and characterized using XRD and SEM analyses. The optical properties of these materials were investigated using UV-vis, PL, and FTIR analyses. Additionally, the graphene aerogel was prepared by drying under ambient pressure. The composite of these two materials was prepared using a droplet casting method. To study the photothermal effect, these materials were exposed to visible light irradiation with an intensity of 2000 W/m2 for one hour. The temperature changes of different concentrations (10, 20, and 30 g/l) of these materials were compared to pure water, both in the presence and absence of light, and it was found that the presence of these materials in water leads to an increase in temperature changes and the rate of water evaporation. with an increase in the concentration of nano-flowers in water, the temperature showed a significant increase, reaching 48.4 degrees Celsius at a concentration of 30 g/l, compared to 25 degrees Celsius initially. moreover, the amount of water mass reduction, indicating water evaporation, reached 3.64 kg/m2 at the highest concentration. Furthermore, the graphene aerogel/Cu2S nanoflower composite was used to simultaneously investigate the effects of both materials in water at different concentrations, and the results showed after 60 minutes, the composite with a concentration of 30 g/l caused a temperature change of approximately 32 degrees Celsius, which is 8.6 degrees higher than Cu2S alone and 4 degrees higher than graphene aerogel alone. The reduction in water mass in the presence of this composite under visible light irradiation at an intensity of 2000 W/m2 reached 3.96 kg/m2.

In this study, ZnCdTeS quantum dots (QDs) with luminescent properties at different emission wavelengths were utilized to enhance the dielectric and electro-optical characteristics of nematic liquid crystal (NLC) cells. At various temperatures, the dielectric permittivity components (ɛ‖ and ɛꓕ) and dielectric anisotropy (Δɛ) of NLC samples containing ZnCdTeS QDs were measured. ɛ‖ increases considerably more than ɛꓕ in the nematic phase when QDs are introduced. The dielectric anisotropy of the system has increased by approximately 19% in the presence of QDs with red emission, which is a result of a significant enhancement of ɛ‖. The NLC environment induces one-dimensional arrays of QDs in the system, which enhances the dielectric properties of the system, as demonstrated by the dielectric results. The electro-optical findings indicate that including QDs substantially reduces the threshold voltage of NLC cells. Incorporating quantum dots into liquid crystal led to a reduction in the threshold voltage from 2.57 V for pure NLC to 2.21 V. QDs improve the effective field of a system by reducing the screening effects caused by ionic impurities in the system. Anisotropy enhancement, effective field increase within the cell, and QD-NLC interaction improvement all contribute to the enhancement of the cell's switching characteristics.

The human enzyme carbonic anhydrase II (HCA II) is a cytosolic protein located in the membrane of red blood cells, and it is involved in various physiological and pathological processes. It can catalyze the reversible hydration of carbon dioxide efficiently. Given the critical role of the HCA II, computational methods such as molecular dynamics simulation (MD) are used to study the structure and dynamics of the wild-type and the mutant enzymes. Based on the previous experimental studies, mutant enzymes enhance kinetic activity or decrease stability. Before MD, quantum mechanics studies were performed. The native enzyme was in a stable state after MD in terms of potential energy and Gibbs-free energy. As evidenced by RMSD, RMSF, and Rg, One of the mutated enzymes that affect the activity of the enzyme has more stability, less fluctuation, and less Rg than other enzymes. In two other mutants that also affected the stability of the enzyme, compared to the previous two enzymes, lower stability, more fluctuations, and potential energy level were observed, which caused the instability of these enzymes during the simulation. These results can help in the engineering and design of new variants of carbonic anhydrase enzyme.

Crocin is one of effective ingredients of saffron, which directly affects saffron's quality and commercial value. Herein, a simple method has been developed based on magnetic molecularly imprinted polymers (MMIPs) for sensitive and selective extraction of crocin from saffron. MMIPs were prepared using gentiobiose as the template molecule, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linking agent, and Fe3O4@SiO2 as the magnetic support. Nanoparticle characterizations were performed using various techniques, including Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), and thermogravimetric analysis (TGA). Different parameters affecting extraction efficiency, isothermal absorption experiments, kinetics absorption experiments, and the selectivity of MMIPs was studied. The analytes were determined by UV-Vis spectrometry and high-performance liquid chromatography (HPLC). The result showed that the pseudo-second-order model describes the sorption of crocin, and the adsorption equilibrium data fit with the Freundlich model. Also, the sorbent had a homogeneous structure, and the crocin sorption occurred through multilayer reversible sorption. Under the optimized conditions, the linear range was between 0.05-50 mgL-1. The limit of detection and limit of quantification were 0.014 and 0.10 mgL-1, respectively. The proposed method in extracting crocin from real samples showed satisfactory results.