-
حرية الوصول المقاله
1 - Synthesis and characterization of gold nanoparticles via submerged arc discharge based on a seed-mediated approach
Ali Akbar AshkarranAbstractGold nanoparticles were prepared via liquid arc discharge technique using a seed-mediated approach in solution and characterized by dynamic light scattering, UV–vis spectroscopy, X-ray diffraction, optical imaging, and atomic force microscopy. A surface plasmon أکثرAbstractGold nanoparticles were prepared via liquid arc discharge technique using a seed-mediated approach in solution and characterized by dynamic light scattering, UV–vis spectroscopy, X-ray diffraction, optical imaging, and atomic force microscopy. A surface plasmon resonance was observed around 520 nm based on optical absorption spectroscopy of as-prepared samples at 15 A arc current in HAuCl4 solution. It was found that sodium citrate acts as a stabilizer and surface capping agent of the colloidal nanoparticles. It was found that the intensity of the plasmonic peak of as-prepared gold nanoparticles in 1 min arc duration gradually increases due to seed mediation up to 6 h. The formation time of gold nanoparticles in higher seed concentrations is less than the lower seed concentrations. تفاصيل المقالة -
حرية الوصول المقاله
2 - Effect of doped Zn–PbI2 nanostructures on structural and electrical properties of photodetector applications
Safaa Idan Mohammed Haider Mohammed Shanshool Khalil Ibraheem ImhanAbstractThe present study focuses on the structural and electrical properties of doped zinc–lead iodide (Zn–PbI2) as-deposited film. Lead iodide (PbI2) nanostructure was successfully prepared by thermal evaporation method on a glass substrate at room temperature. The an أکثرAbstractThe present study focuses on the structural and electrical properties of doped zinc–lead iodide (Zn–PbI2) as-deposited film. Lead iodide (PbI2) nanostructure was successfully prepared by thermal evaporation method on a glass substrate at room temperature. The analysis, characterization, and structural properties of PbI2 were achieved using X-ray diffraction (XRD) and scanning electron microscopy. The PbI2 was polycrystalline and had a hexagonal structure as proved using XRD. The measured values are in agreement with other experimental and theoretical data. Furthermore, the present research studied the effect of doping on the physical properties of lead iodide with zinc dopants at different weights (0.02, 0.04, 0.06, and 0.08) mg. The electrical properties of the fabricated metal–semiconductor–metal photodetector based on PbI2 and Pb1−xZnxI2 layers prepared on glass substrates by thermal evaporation method were investigated. The obtained results of Schottky barrier heights for Pb0.98Zn0.02I2 were significant. The current–voltage characteristics of the Pb0.98Zn0.02I2 thin film have acted as a Schottky contact in dark and under white light, 460-nm light. The light responsivity has shown a peak at 460-nm chopped light. At a bias voltage of 1, 3, and 5 V, the photocurrent rise and decay times were investigated. The device has shown faster response times for 460-nm light. This fast response was attributed to the high quality of polycrystalline and showed a high quantum efficiency of 9.19 × 102% when it was illuminated by 460-nm light under the bias of 3 V. تفاصيل المقالة -
حرية الوصول المقاله
3 - Rapid growth of zinc oxide nanobars in presence of electric field by physical vapor deposition
Mehraban Jouya Fahime Taromian Simin SiamiAbstractIn this contribution, electric field has some effects to increase growth for specific time duration on zinc oxide (ZnO) nanobars. First, the zinc (Zn) thin film has been prepared by 235,000 V/m electric field assisted physical vapor deposition (PVD) at vacuum of أکثرAbstractIn this contribution, electric field has some effects to increase growth for specific time duration on zinc oxide (ZnO) nanobars. First, the zinc (Zn) thin film has been prepared by 235,000 V/m electric field assisted physical vapor deposition (PVD) at vacuum of 1.33 × 10−5 mbar. Second, strong electric field of 134,000 V/m has been used in ambient for growing ZnO nanobars in term of the time include 2.5 and 10 h. The performances of the ZnO nanostructure in absence and presence of electric field have been determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results of XRD analysis showed that ZnO has a hexagonal bars structure and a strongly preferred (101) orientation which is strongest than without applying electric field. SEM analysis revealed that physical vapored ZnO thin film in presence of electric field are densely packed with uniform morphological, thinner and denser in distribution. Electric field effect for ZnO growth in 2.5 h is better than it in the 2.5 h without electric field but by passing the time the media influence has good power almost as same as electric field. Through this electric field in PVD, the compact and uniform Zn film has been achieved which is less diameter than ordinary PVD method. Finally, we carry out a series of experiments to grow different-orientation ZnO nanobars with less than 100 nm in diameter, which are the time saving process in base of PVD ever reported. Therefore, the significant conclusion in usage electric field is reducing time of growth. تفاصيل المقالة -
حرية الوصول المقاله
4 - ارزیابی ریزساختاری پیشرفت واکنش‌های پوزولانی آهک در تثبیت و جامدسازی آلاینده‌های فلز سنگین روی
وحیدرضا اوحدی محمد امیری محمدحسن باقرزمینه و هدف: هدف این پژوهش مطالعه نحوه فرایند اندر کنش پولک های رسی - آلاینده فلز سنگین - آهک در طی زمان از منظر ریزساختار است. روش بررسی: برای رسیدن به این هدف، درصدهای مختلف آهک به خاک رسی طبیعی حاوی آلاینده فلز سنگین روی افزوده‌شده و مکانیزم نگه داری آلاینده توسط برر أکثرزمینه و هدف: هدف این پژوهش مطالعه نحوه فرایند اندر کنش پولک های رسی - آلاینده فلز سنگین - آهک در طی زمان از منظر ریزساختار است. روش بررسی: برای رسیدن به این هدف، درصدهای مختلف آهک به خاک رسی طبیعی حاوی آلاینده فلز سنگین روی افزوده‌شده و مکانیزم نگه داری آلاینده توسط بررسی تغییرات pH و ارزیابی مطالعه ریزساختاری (XRD) مورد تجزیه و تحلیل قرار گرفته است. بحث و نتیجه گیری: نتایج پژوهش حاضر نشان می دهد که افــزایش 10% آهــک علاوه بر فرایند تثبیت موجب شده در غلظت cmol/kg-soil250 آلاینده فلز سنگین روی، میزان نگه داری آلاینده بیش از 37% افزایش یابد. ارزیابی پراش پرتو ایکس نشان می دهد که حضور آلاینده فلز سنگین موجب کاهش فرایند اندرکنش آهک و رس و متعاقب آن کاهش تشکیل نانوساختار هیدرات سیلیکات کلسیم (C-S-H) و هیدرات آلومینیات کلسیم (C-A-H) شده است. بر اساس نتایج آزمایش پراش اشعه ایکس و قابلیت نگه داری آلاینده در نمونه های اصلاح‌شده با کمتر از 6% آهک، احتمالاً علت اصلی کاهش شدت قله نظیر کانی رسی، حضور آلاینده فلز سنگین بوده است. نتایج تحقیق حاضر نشان میدهد که تشکیل نانوساختار C-S-H به واسطه مساحت سطح ویژه زیاد، مشخصه های جذب را بهبود می‌بخشد و از طریق کپسوله کردن یون های فلز سنگین (جامدسازی) میزان تحرک پذیری آلاینده را کاهش می دهد. همچنین حضور آلاینده فلز سنگین روی سبب کاهش مقدار تشکیل نانوساختار C-S-H می شود. به نحوی که حضور cmol/kg-soil 25 آلاینده فلز سنگین روی، شدت قله نانوساختار C-S-H را حدود CpS 90 کاهش داده است. تفاصيل المقالة -
حرية الوصول المقاله
5 - Preparation, Characterization and Photocatalytic Activity of Ag-Cd-ZnO and Ag-Cu-ZnO Nanostructures
Bahar Khodadadi Maryam Bordbar Maryam SajediIn this study, ZnO nanopowders and ZnO doped with metals (Cu , Ag- doped ZnO) and (Cd, Ag- doped ZnO) were synthesized by the sol-gel method in order to investigation on the codoping effect on the band gap and photocatalytic activity of ZnO. The synthesized samples are أکثرIn this study, ZnO nanopowders and ZnO doped with metals (Cu , Ag- doped ZnO) and (Cd, Ag- doped ZnO) were synthesized by the sol-gel method in order to investigation on the codoping effect on the band gap and photocatalytic activity of ZnO. The synthesized samples are characterized by IR spectroscopy technique. Moreover, the absorption coefficients of the ZnO, Ag-Cd-ZnO and Ag-Cu-ZnO were analyzed by Tauc’s approach and the direct band gap is calculated. According to these results, compared with pure ZnO, the band gap of the Ag-Cd-ZnO and Ag-Cu-ZnO decreases and it is dependent on the content of dopands. Furthermore, photocatalytic activity for all samples was investigated under UV irradiation in an aqueous medium. The results have been revealed that Ag-Cd-ZnO and Ag-Cu-ZnO shown more photocatalytic actitivity in comparison with pure ZnO. تفاصيل المقالة -
حرية الوصول المقاله
6 - Substrate Temperature Effect on Photovoltaic Performance of Lead Sulfide (PbS) Nanostructures Deposited by Chemical Vapor Deposition (CVD) Method
Mohsen Cheraghizade Ramin Yousefi Farid Jamali-SheiniPbS nanostructures for solar cell application, deposited in different substrate temperatures by CVD method. FESEM images show nanostructures with rod and spherical volumes and porous surface for samples. XRD analysis verified formation of cubic crystalline nanostructure أکثرPbS nanostructures for solar cell application, deposited in different substrate temperatures by CVD method. FESEM images show nanostructures with rod and spherical volumes and porous surface for samples. XRD analysis verified formation of cubic crystalline nanostructures. Photovoltaic measurements also shown that with increasing in substrate temperature, efficiency conversion of cells was increased. تفاصيل المقالة -
حرية الوصول المقاله
7 - Magnetic and Structural Characteristics of Fe2O3 Nanostructure Synthesized in the Presence of Sour Cherry Juice
Mahboubeh Kargar Majid Ghashang Mohammad Reza Mohammad ShafieeT The nanostructures of Fe2O3 have been synthesized applying sour cherry juice and iron chloride as a low-cost and eco-friendly method at ambient conditions. Sour cherry juice has been used as a surfactant and the kind of surfactant had an important effect on the size أکثرT The nanostructures of Fe2O3 have been synthesized applying sour cherry juice and iron chloride as a low-cost and eco-friendly method at ambient conditions. Sour cherry juice has been used as a surfactant and the kind of surfactant had an important effect on the size and morphology of the products. The effect of sour cherry juice concentration and calcination temperature on the morphologies of Fe2O3 nanostructures has been investigated. The prepared nanoparticles were subjected to X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FE-SEM), and vibrating sample magnetometer (VSM) system. The powder X-ray diffraction analysis confirmed that Fe2O3 nanostructures are in Rhombohedral and Cubic phases. The average crystalline size estimated by the Williamson-hall method was about 13-32 nm for all samples. Various morphologies were also obtained by changing the amount of sour cherry juice. The saturation magnetization increased with the growth of crystals. تفاصيل المقالة -
حرية الوصول المقاله
8 - Efficient photocatalytic desulfurization of thiophene under visible light irradiation over flower-like AgBiS2 photocatalyst
Mehdi Mousavi-Kamazani Reza Rahmatolahzadeh Hassan NajafianHere, we report the production of hierarchical flower-like AgBiS2 nanostructures by an amino acid-modified polyol route. This work indicates that by changing the polyol process conditions including kind of capping agent, reaction time and reflux temperature, the sheet-l أکثرHere, we report the production of hierarchical flower-like AgBiS2 nanostructures by an amino acid-modified polyol route. This work indicates that by changing the polyol process conditions including kind of capping agent, reaction time and reflux temperature, the sheet-like, cone-like, sphere-like and flower-like morphologies of AgBiS2 micro/nanostructures can be prepared. The phase, elemental composition, morphology and optical characteristics of as-prepared AgBiS2 nanostructures were analyzed by UV–Vis, FESEM, XRD, and EDS techniques. After characterization of the products, the AgBiS2 nanostructures were employed as novel photocatalysts for oxidative desulfurization of thiophene/n-octane solution as model fuel under visible light illumination. Results demonstrate that hierarchical flower-like AgBiS2 photocatalyst with desirable band gap energy (2.44 eV) has high photocatalytic desulfurization performance of about 89% after 2 h of visible light irradiation. As well as, the effects of morphology, photocatalyst dosage and reusability of the AgBiS2 nanostructures on the photocatalytic performance were evaluated. The excellent photocatalytic activity of AgBiS2 photocatalyst can be attributed to the strong visible light absorption, high separation rate of electron–hole pairs, special hierarchical structures and suitable band gap energy. Moreover, a reliable photo-oxidation desulfurization mechanism was discussed according to the active species trapping experiments, which revealed the photo-generated h+ and •O2− radicals were the main active species in the photocatalytic desulfurization process. تفاصيل المقالة -
حرية الوصول المقاله
9 - Theoretical investigation of optical properties of Aluminum zig-zag thin films
Maryam Gholizadeh Arashti Mahsa FakharpourThe transmission matrix method was applied to model the reflection and transmission co-polarization spectra of zig-zag aluminum thin films by different arm numbers and lengths and the optical spectra of the zig-zag nanostructures for both s- and p- polarized lights were أکثرThe transmission matrix method was applied to model the reflection and transmission co-polarization spectra of zig-zag aluminum thin films by different arm numbers and lengths and the optical spectra of the zig-zag nanostructures for both s- and p- polarized lights were obtained at different incident angles. According to the results, for the s- polarized incident light, the transmission reduces and the reflection increases by incident angle. For the p- polarized light, the reflection reduces else for the incident directions near the Bruster’s angle and the transmission almost remains constant. The numbers of Bragg peaks via arm number were also considered for s-polarized light at the 〖60〗^° incident angle. The results determined four arms as the period of zig-zag structure. Besides, the red and blue shifts were observed for the wavelengths smaller and greater than 550 nm, respectively. At last, no Bragg peak was observed for p-polarized light at all incident angles. تفاصيل المقالة -
حرية الوصول المقاله
10 - Pechini Sol-Gel Synthesis and Characterization of NiWO4/W5O14/WO3 Nanocomposite for Photocatalytic Desulfurization of Thiophene
Mehdi Mousavi-Kamazani Mahvash Siahmansouri Mohammad GhodratiOne of the most important problems in the oil industry is the presence of sulfur and sulfur compounds in crude oil. Sulfur compounds in crude oil can have detrimental effects on the environment, equipment, catalysts, and end products. One of the most important goals of أکثرOne of the most important problems in the oil industry is the presence of sulfur and sulfur compounds in crude oil. Sulfur compounds in crude oil can have detrimental effects on the environment, equipment, catalysts, and end products. One of the most important goals of researchers in recent years is to sweeten petroleum products from these compounds. This study aims to use NiWO4/W5O14/WO3 composite nanostructure to solve this problem using the photocatalytic oxidative desulfurization method. This composite nanostructure has been synthesized by Pechini sol-gel method with high purity at low temperature and examined by XRD, EDS, FESEM, and FT-IR analysis. Due to the presence of WO3 in the composition, the bandgap was greatly reduced and the efficiency was increased. As a result, the nanostructure could degrade more than 73% of the sulfur in thiophene in 180 min under visible light. By optimizing the amount of photocatalyst and irradiation time, the efficiency can be improved. تفاصيل المقالة -
حرية الوصول المقاله
11 - Efficient photocatalytic desulfurization of thiophene under visible light irradiation over flower-like AgBiS2 photocatalyst
Mehdi Mousavi-Kamazani Reza Rahmatolahzadeh Hassan NajafianHere, we report the production of hierarchical flower-like AgBiS2 nanostructuresby an amino acid-modified polyol route. This work indicates that by changing thepolyol process conditions including kind of capping agent, reaction time and refluxtemperature, the sheet-like أکثرHere, we report the production of hierarchical flower-like AgBiS2 nanostructuresby an amino acid-modified polyol route. This work indicates that by changing thepolyol process conditions including kind of capping agent, reaction time and refluxtemperature, the sheet-like, cone-like, sphere-like and flower-like morphologies ofAgBiS2 micro/nanostructures can be prepared. The phase, elemental composition,morphology and optical characteristics of as-prepared AgBiS2 nanostructures wereanalyzed by UV–Vis, FESEM, XRD, and EDS techniques. After characterization ofthe products, the AgBiS2 nanostructures were employed as novel photocatalystsfor oxidative desulfurization of thiophene/n-octane solution as model fuel undervisible light illumination. Results demonstrate that hierarchical flower-like AgBiS2photocatalyst with desirable band gap energy (2.44 eV) has high photocatalyticdesulfurization performance of about 89% after 2 h of visible light irradiation.As well as, the effects of morphology, photocatalyst dosage and reusability ofthe AgBiS2 nanostructures on the photocatalytic performance were evaluated.The excellent photocatalytic activity of AgBiS2 photocatalyst can be attributedto the strong visible light absorption, high separation rate of electron–hole pairs,special hierarchical structures and suitable band gap energy. Moreover, a reliablephoto-oxidation desulfurization mechanism was discussed according to theactive species trapping experiments, which revealed the photo-generated h+ and•O2− radicals were the main active species in the photocatalytic desulfurizationprocess. تفاصيل المقالة -
حرية الوصول المقاله
12 - Synthesis and Characterization of forsterite nanopowder ceramic via mechanical activation
Hassan GHEISARIThis project investigates the synthesis of single-phase nano crystalline forsteritepowder by mechanical activation with subsequent annealing. To produceforsterite powder, a mixture of talc and magnesium oxide powders was first milledby a planetary ball mill, and then an أکثرThis project investigates the synthesis of single-phase nano crystalline forsteritepowder by mechanical activation with subsequent annealing. To produceforsterite powder, a mixture of talc and magnesium oxide powders was first milledby a planetary ball mill, and then annealed at 1000 and 1200 8C for 1 h. Thesynthesized powder was characterized by X-ray diffraction (XRD), simultaneousthermal analysis (STA), scanning electron microscopy (SEM), and atomicabsorption spectrometry (AAS). The initial temperature of forsterite crystallizationwas reduced to about 825 8C after 20 h of mechanical activation. The forsteritepowder synthesized by 5 h of mechanical activation with subsequent annealingat 1000 8C for 1 h had crystallites 40 n min size. The particle size of this samplewas less than 500 nm. تفاصيل المقالة -
حرية الوصول المقاله
13 - An efficient synthesis of α,α'-benzylidene bis(4-hydroxycoumarin) derivatives catalyzed by Tl2O3 nanoparticles
Mohammad Reza NazarifarIn this work, we attempted to synthesize thallium (III) oxide nano structures by direct thermal decomposition using thallium I phenylsuccinic acid coordination polymer [Tl(PsucH)]n as a precursor. Also, Tl2O3 nanoparticles have been characterized by scanning electron mi أکثرIn this work, we attempted to synthesize thallium (III) oxide nano structures by direct thermal decomposition using thallium I phenylsuccinic acid coordination polymer [Tl(PsucH)]n as a precursor. Also, Tl2O3 nanoparticles have been characterized by scanning electron microscopy (SEM), X-Ray powder diffraction (XRD) and IR spectroscopy and then we report a simple and efficient method for the synthesis of α,α'-benzylidene bis(4-hydroxycoumarin) derivatives by aromatic aldehyde and 4-hydroxycoumarin by using Tl2O3 nanoparticles in H2O/EtOH at room temperature. A wide spectrum of functional groups, were tolerated in the developed protocol. The target molecules were obtained in good to excellent yield applying the current method. The catalyst can be recover for the subsequent reactions and reused without loss of activity. تفاصيل المقالة -
حرية الوصول المقاله
14 - Sonochemical synthesis of undoped and Co-doped ZnO nanostructures and investigation of optical and photocatalytic properties
Bahar Khodadadi Maryam BordbarIn this paper, undopedZnO and Co-ZnOnano structureswith different molar ratio of Cobalt have been synthesized by the sonochemical method. Structure have been characterized by Fourier Transform (FTIR) and UV–Vis spectroscopy,Scanning Electron Microscopy (SEM), Ener أکثرIn this paper, undopedZnO and Co-ZnOnano structureswith different molar ratio of Cobalt have been synthesized by the sonochemical method. Structure have been characterized by Fourier Transform (FTIR) and UV–Vis spectroscopy,Scanning Electron Microscopy (SEM), Energy Dispersive Analytical X-Ray (EDAX), and X-Ray Diffraction (XRD) methods. Moreover, the direct band gap has been calculated by Tauc’s approach.Moreover, mean crystal size has been estimated by Scherrerequaton. Furthermore, photocatalytic activity for all samples has been investigated under UV irradiation in an aqueous medium. Compared with pure ZnO, the band gap of the Co-ZnOhas been shown decrease and it is dependent on the content of dopants. Also, photocatalytic activity improves in the presence of cobalt dopant. تفاصيل المقالة -
حرية الوصول المقاله
15 - A simple synthetic technique to produce ZnO/Fe2O3/Fe3O4 nanostructures and application as a photocatalyst
Nai-Feng Hsu Kuei-Ting HsuIn this study, a simple technique was used for synthesizing one-dimensional ZnO/Fe2O3/Fe3O4 nanostructures (NSs) through heat treatment under vacuum by using a magnetic field at a temperature of 200 °C for 1 h. The photocatalytic effect of the NSs were studied by de أکثرIn this study, a simple technique was used for synthesizing one-dimensional ZnO/Fe2O3/Fe3O4 nanostructures (NSs) through heat treatment under vacuum by using a magnetic field at a temperature of 200 °C for 1 h. The photocatalytic effect of the NSs were studied by decomposing methyl orange (MO) dye (5 mg/L, pH = 8.1) under ultraviolet illumination. The experimental results indicated that a 33-mg/L ZnO/Fe2O3/Fe3O4 NS-containing film on glass could reduce the MO concentration by 37% in 100 min, and the synthesized ZnO/Fe2O3/Fe3O4 NS-containing films could be reused to degrade MO solution. Moreover, 0.1 g/L of ZnO/Fe2O3/Fe3O4 NS-containing powder exhibited an excellent photocatalytic effect and reduced the MO concentration by almost 90% in 100 min. تفاصيل المقالة -
حرية الوصول المقاله
16 - مدل‌سازی چگالی حامل‌های بار در سلول خورشیدی نانوساختاری حالت جامد حساس شده با رنگدانه
تهمینه جلالی مرتضی صادقی شهریار عصفوریسلولهای خورشیدی حساس شده با رنگدانه نسل جدیدتری از سلول‌های خورشیدی هستند که اگرچه بازده پایین‌تری نسبت به سلول‌های سیلیکونی دارند، اما پتانسیل بالایی برای بازده بیشتر دارند و چون از نظر اقتصادی صرفه بهتری دارند، اگر بازده و پایداری آنها افزایش یابد می‌توانند جایگزین أکثرسلولهای خورشیدی حساس شده با رنگدانه نسل جدیدتری از سلول‌های خورشیدی هستند که اگرچه بازده پایین‌تری نسبت به سلول‌های سیلیکونی دارند، اما پتانسیل بالایی برای بازده بیشتر دارند و چون از نظر اقتصادی صرفه بهتری دارند، اگر بازده و پایداری آنها افزایش یابد می‌توانند جایگزین سلول‌های خورشیدی سیلیکونی در بازار شوند. طراحی و توسعه روزافزون سلول‌های خورشیدی تنها محدود به کارهای تجربی و آزمایشگاهی نبوده، بلکه مدلسازی‌های عددی نیز در این امر دخیل بوده است. هدف از انجام این تحقیق طراحی و مدل‌سازی عددی سلول¬های خورشیدی حالت جامد حساس شده با رنگدانه بر پایه لایه نانوساختار نیمرسانا با گاف نواری عریض (دی-اکسیدتیتانیوم) و همچنین اکسید روی به عنوان انتقال دهنده الکترون و رنگدانه N719 به عنوان لایه جاذب و همچنین PEDOT:PSS و P3HT به عنوان ماده انتقال دهنده حفره است. در این پژوهش از نرم افزار کامسول برای طراحی سلول خورشیدی استفاده و مشخصه‌های جریان-ولتاژ و همچنین جذب اپتیکی سلول محاسبه شده است که با داده‌های تجربی مطابقت خوبی دارد. تفاصيل المقالة -
حرية الوصول المقاله
17 - مشخصه‌یابی ساختار پروسکیتی نانوذرات YbMnO3 سنتز شده با روش ترسیب الکتروانباشت
حمید محمد شیری صائب صادقی رضا صفری علی احسانی حمیدرضا ابراهیمی حمید هادیپروسکیت ها ترکیباتی هستند که دارای فرمول عمومی ABO3، مانند YbMnO3,، می باشند. در این پژوهش، از روش رسوب گیری الکتروشیمیایی، به عنوان یک روش جدید و مقرون به صرفه، برای سنتز نانو ترکیب پروسکیتی YbMnO3 استفاده شد. سپس، آزمون های مشخصه یابی XRD, DSC, SEM و EDS بر روی نمونه أکثرپروسکیت ها ترکیباتی هستند که دارای فرمول عمومی ABO3، مانند YbMnO3,، می باشند. در این پژوهش، از روش رسوب گیری الکتروشیمیایی، به عنوان یک روش جدید و مقرون به صرفه، برای سنتز نانو ترکیب پروسکیتی YbMnO3 استفاده شد. سپس، آزمون های مشخصه یابی XRD, DSC, SEM و EDS بر روی نمونه سنتزی انجام و نتایج به دست آمده مورد تجزیه و تحلیل قرار گرفت. به علاوه، خصوصیات ریخت شناسی و ساختاری نانو ماده سنتزی نشان داد که محصول اصلی YbMnO3 با ساختار کلوخه ای در مقیاس نانو است که اندازه ذرات آن نیز nm 5/35 تخمین زده شد. همچنین، برخی کمیت‌های مکانیکی، مانند تنش، کرنش، ثابت‌های شبکه و اندازه ذرات تشکیل‌دهنده ترکیب پروسکیتی سنتزی، با استفاده از معادله شرر و روش ویلیامسون- هال محاسبه و نتایج به دست آمده با نتایج (مقادیر) به دست آمده از طیف‌های XRD و SEM مقایسه شد. پیش‌بینی می شود، نتایج این پژوهش بتواند افق های جدیدی را در سنتز کم هزینه نانومواد و نانو ذرات سازگار با محیط‌زیست (شیمی سبز) باز نماید. تفاصيل المقالة -
حرية الوصول المقاله
18 - ساخت و بهینه‌سازی حسگر حساس به رطوبت مبتنی بر نانوساختارهای متخلخل تری-اکسید تنگستن/نانوذرات نقره
ایوب کریم زادقویدل غلامرضا کیانی مهسا مهدوی نیاهدف این تحقیق، ساخت حسگری رطوبتی بر پایه نانوساختار متخلخل تری‌اکسید تنگستن خالص و دوپ شده با نانوذرات نقره و استفاده از خصوصیات تغییرات اهمی، ظرفیت خازنی و امپدانسی آن در مقابل رطوبت به عنوان خروجی است. مشخصات ساختاری نانوکامپوزیت تهیه شده، توسط میکروسکوپ الکترونی روبش أکثرهدف این تحقیق، ساخت حسگری رطوبتی بر پایه نانوساختار متخلخل تری‌اکسید تنگستن خالص و دوپ شده با نانوذرات نقره و استفاده از خصوصیات تغییرات اهمی، ظرفیت خازنی و امپدانسی آن در مقابل رطوبت به عنوان خروجی است. مشخصات ساختاری نانوکامپوزیت تهیه شده، توسط میکروسکوپ الکترونی روبشی و دستگاه پراش اشعه ایکس مورد بررسی قرار گرفت. نتایج نشان داد که تری‌اکسید تنگستن سنتزی به شکل کره‌هایی با ابعاد 3 تا 7 میکرومتر با ساختار متخلخل سطحی در اندازه 10 تا 60 نانومتر می‌باشد. برای تولید حسگرها، نخست مواد ترکیب و پراکنده‌سازی شد، سپس با روش ته‌نشینی بر روی مدار الکترود شانه‌ای لایه‌نشانی گردید. بررسی‌ها نشان داد حسگر دوپ شده با نانوذرات نقره، عملکرد بهتری در مقایسه با نمونه تری‌اکسید تنگستن خالص دارد. حساسیت این حسگر برای محدوده رطوبت نسبی50-20% و 90-50%، به‌ترتیب 4/4 و MΩ/%RH 68/0 بدست آمد که در مقایسه با نمونه‌های پیشین، 7 و 5% بهبود یافته است. زمان پاسخ و بازگشت این حسگر 2 و 7 ثانیه اندازه‌گیری شد که به‌ترتیب 5/37 و 4/41 برابر کوچکتر از نمونه‌های دردسترس است. کاهش ظرفیت خازنی حسگر تا Pf 3800، با افزایش رطوبت نسبی به 90% از سایر یافته‌ها است. تغییرات امپدانسی قابل توجه حسگر در برابر تغییرات رطوبت از سایر نتایج مهم است که نشان میدهد که امپدانس می‌تواند با جبران خطاهای ناشی از تغییرات اهمی و ظرفیت خازنی، به عنوان خروجی حسگر در نظر گرفته شود. تفاصيل المقالة -
حرية الوصول المقاله
19 - افزایش بازده سلول‌های خورشیدی رنگدانه‌ای با استفاده از نانوبلورهای طلای پلاسمونیک با پوشش TiO2و SiO2
لیلا شعبانی احمد محمدی تهمینه جلالیدر این پژوهش، سنتز نانوذرات پلاسمونیک به روش انحلال شیمیایی و در سه مرحله انجام گرفت. سپس به بررسی نانوساختارهای هسته-پوسته Au@TiO2 و Au@SiO2 پرداخته شده است. این نانوذرات به عنوان فوتوآند در سلول‌های خورشیدی رنگدانه‌ای(DSSCs) استفاده شدند. پارامترهایی مانند جریان اتصال أکثردر این پژوهش، سنتز نانوذرات پلاسمونیک به روش انحلال شیمیایی و در سه مرحله انجام گرفت. سپس به بررسی نانوساختارهای هسته-پوسته Au@TiO2 و Au@SiO2 پرداخته شده است. این نانوذرات به عنوان فوتوآند در سلول‌های خورشیدی رنگدانه‌ای(DSSCs) استفاده شدند. پارامترهایی مانند جریان اتصال کوتاه، ولتاژ مدار باز، فاکتور پرشدگی و بهره تبدیل سلول خورشیدی رنگدانه‌ای مورد بررسی قرار گرفت. سلولی که در آن از Au@TiO2 که با لیگاند مرکاپتو استیک اسید سنتز شده، استفاده شده است، بیشترین کارایی را دارد. علت این امر، افزایش اثر میدان نزدیک در نانوساختارهای هسته-پوسته طلا و ایجاد جریان نوری تقویت شده ناشی از پلاسمونیک پیش بینی شده است. تفاصيل المقالة -
حرية الوصول المقاله
20 - A Deep Survey upon the Synthesis of AuS Nanostructures
Kourosh Motevalli Zahra YaghoubiIn this research, the dendritic gold(I) sulfide nanostructures were successfully synthesized by a simple hydrothermal route. The effect of temperature , and reaction time, on the morphology and particle dimension was alsoinvestigated. Thus, the efficiency of synth أکثرIn this research, the dendritic gold(I) sulfide nanostructures were successfully synthesized by a simple hydrothermal route. The effect of temperature , and reaction time, on the morphology and particle dimension was alsoinvestigated. Thus, the efficiency of synthesized gold sulfide nanostructures in thin-film solar cells was evaluated. The results indicated very well that the particle dimension and morphology have effect on solar cells efficiency and dendritic gold sulfide nano-structures have higher efficiency compared to sphericaland rod-like gold sulfide nanostructures. Moreover, depositing of dendritic gold sulfide upon gold sulfide nanoparticles led to obtaining 3.28% cell efficiency that in comparison with sole dendritic nanostructures and sole nanoparticles (1.89%), efficiency improvements of 48 and 85% were, respectively,obtained and also this important point must be elucidated that this nanostructures are useful for mechanical usages especially in manufacturing some linked rings in water treatment installations. Also, if we want to be decided for comparing with similar works presented for gold sulfide preparation [1–10],then, this fact will be illuminated easily that we synthesized dendritic gold sulfide nano-structures using new initiating reagents and without using surfactants by an easy route which can be more able in solar cells. تفاصيل المقالة
سند
Sanad is a platform for managing Azad University publications
الروابط
المراكز ذات الصلة
دعامة
الصفحات الرسمية
حقوق هذا الموقع الإلكتروني مملوكة لنظام SANAD Press Management. © 1442-1445