Nanoscience and Nanotechnology

Here, the effect of lightly Niobium doped TiO2 layer on the performance of perovskite solar cells has been studied by using solar cell capacitance simulator (SCAPS). N addition, the effects of Niobium concentration, buffer film thickness and operating temperature on the performance of the perovskite solar cell are investigated. For doping level of 3.0 mol% into the TiO2 layer, cell efficiency of 18.26% with Voc of 0.96 V, Jsc of 22.45 mA/ cm2 and FF of 84.25% has been achieved. Calculations show that thickness widening of Nb-doped TiO2 layer would decrease the efficiency and Voc of the cells. Increase in operating temperature from 300 k to 400 k would weaken the performance of the perovskite solar cell with both pure and Nb-doped TiO2 layers. However, the cell with Nb-doped TiO2 layer shows higher stability than the cell with pure TiO2 buffer at higher temperatures. The efficiency of the cell with pure and doped buffer layers decreased from 15.52% to 11.47% (with 26.09% reduction) a...

Nanoparticles, 10–14 nm, consisting of either Fe3O4 or Co0.2Fe2.8O4 stabilized with oleic acid, were prepared using solution combustion. Their structural and magnetic properties were examined using X-ray diffractometry, scanning electron microscopy, vibrating sample magnetometry, and Fourier-transform infrared spectroscopy. The properties of both sets of materials are similar, except that the cobalt-doped particles are considerably less magnetic. The in vitro inhibitory activities of the nanoparticles were assessed against pathogenic bacteria Shigella dysenteriae, Klebsiella pneumoniae, Acinetobacter baumannii, Streptococcus pyogenes, and pathogenic fungi and molds Candida albicans, Fusarium oxysporum, and Aspergillus fumigatus. The magnetite nanoparticles were moderately effective against all tested pathogens, but the activity of the cobalt-doped nanoparticles was significantly lower, possibly due to an interruption of the Fenton reaction at the bacterial membrane. This work sugges...

The performance of the buffer layer of CIGS thin film solar cell was optimized using SCAPS software to improve the conversion efficiency. In the first step, the validity of empirical and simulation models were verified. After that, four buffer layers of InS, ZnS, ZnO and ZnSe were substituted with CdS in the Glass/ Mo/CIGS/CdS/ZnO/ZnO:Al structure. The results indicated that the Zn-based compounds are proper substitute buffer layers with similar electronic and physical properties due to higher band gap than CdS. Next, the effect of buffer layer thickness was investigated and the optimum thicknesses of buffer layers were achieved. Results revealed that zinc selenide with efficiency of 20.07% can be an appropriate alternative buffer layer for CdS. Also, it is shown that by optimizing the buffer layer thicknesses, the solar cell efficiency raises, mainly due to increase in fill factor.

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Although enhanced ferrite nanoparticles (NPs) have been envisioned for use in future biomedical applications, less attempt has been made to tailoring and optimizing their detailed magnetic properties and specific loss power (SLP) values. Herein, Co x Fe 3−x O 4 (0 × 1) NPs are synthesized using a coprecipitation method at 80°C in the presence of air atmosphere. The effect of varying Co concentration on crystalline, morphological, magnetic and hyperthermia properties is also investigated in detail. Hysteresis loop measurements showed an increase in coercivity (H c) from 7.75 to 340.50 Oe, and a decrease in saturation magnetization (M s) from 59.10 to 32.70 emu g −1 with increasing x=0 (pure magnetite) to x=1 (pure Co ferrite), respectively. In addition to confirming the hysteresis loop results, first-order reversal curve (FORC) analysis estimated a 52% decrease in superparamagnetic (SP) fraction. Hyperthermia measurements carried out under an alternating magnetic field with intensity of 400 Oe and a frequency of 400 kHz showed an increase in SLP from x=0 to x=0.4, and a decrease in SLP for 0.4 <× 1. SLP was maximized at 395 W g −1 for the intermediate concentration of x=0.4. The optimized heat generation of Co 0.4 Fe 2.6 O 4 NPs comprising approximately 50%-50% SP-ferromagnetic fractions may result from the simultaneous contribution of the three following mechanisms: hysteresis loop loss, Brownian and Neel relaxation together with relatively high H c and moderate M s. Abbreviations (NPs) Nanoparticles (SLP) specific loss power (FORC) first-order reversal curve (SP) superparamagnetic (FESEM) field-emission scanning electron microscopy (H c) coercivity (M s) saturation magnetization (K) anisotropy constant