Articles de revues : « Doped Nanostructures »

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Vikal, Sagar, Yogendra K. Gautam, Anit K. Ambedkar, Durvesh Gautam, Jyoti Singh, Dharmendra Pratap, Ashwani Kumar, Sanjay Kumar, Meenal Gupta et Beer Pal Singh. « Structural, optical and antimicrobial properties of pure and Ag-doped ZnO nanostructures ». Journal of Semiconductors 43, n^o 3 (1 mars 2022) : 032802. http://dx.doi.org/10.1088/1674-4926/43/3/032802.

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Abstract In the present work, zinc oxide (ZnO) and silver (Ag) doped ZnO nanostructures are synthesized using a hydrothermal method. Structural quality of the products is attested using X-ray diffraction, which confirms the hexagonal wurtzite structure of pure ZnO and Ag-doped ZnO nanostructures. XRD further confirms the crystallite orientation along the c-axis, (101) plane. The field emission scanning electron microscope study reveals the change in shape of the synthesized ZnO particles from hexagonal nanoparticles to needle-shaped nanostructures for 3 wt% Ag-doped ZnO. The optical band gaps and lattice strain of nanostructures is increased significantly with the increase of doping concentration of Ag in ZnO nanostructure. The antimicrobial activity of synthesized nanostructures has been evaluated against the gram-positive human pathogenic bacteria, Staphylococcus aureus via an agarose gel diffusion test. The maximum value of zone of inhibition (22 mm) is achieved for 3 wt% Ag-doped ZnO nanostructure and it clearly demonstrates the remarkable antibacterial activity.

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Subki, A. Shamsul Rahimi A., Mohamad Hafiz Mamat, Musa Mohamed Zahidi, Mohd Hanapiah Abdullah, I. B. Shameem Banu, Nagamalai Vasimalai, Mohd Khairul Ahmad et al. « Optimization of Aluminum Dopant Amalgamation Immersion Time on Structural, Electrical, and Humidity-Sensing Attributes of Pristine ZnO for Flexible Humidity Sensor Application ». Chemosensors 10, n^o 11 (17 novembre 2022) : 489. http://dx.doi.org/10.3390/chemosensors10110489.

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This study synthesized pristine and aluminum (Al)-doped zinc oxide (Al:ZnO) nanostructures through a simplistic low-temperature ultrasonicated solution immersion method. Al:ZnO nanostructures were synthesized as a sensing material using different immersion times varying from two to five hours. The Al:ZnO nanostructured-based flexible humidity sensor was fabricated by employing cellulose filter paper as a substrate and transparent paper glue as a binder through a simplistic brush printing technique. XRD, FESEM, HRTEM, EDS, XPS, a two-probe I–V measurement system, and a humidity measurement system were employed to investigate the structural, morphological, chemical, electrical, and humidity-sensing properties of the pristine ZnO and Al:ZnO nanostructures. The structural and morphological analysis confirmed that Al cations successfully occupied the Zn lattice or integrated into interstitial sites of the ZnO lattice matrix. Humidity-sensing performance analysis indicated that the resistance of the Al:ZnO nanostructure samples decreased almost linearly as the humidity level increased, leading to better sensitivity and sensing response. The Al:ZnO-4 h nanostructured-based flexible humidity sensor had a maximum sensing response and demonstrated the highest sensitivity towards humidity changes, which was noticeably superior to the other tested samples. Finally, this study explained the Al:ZnO nanostructures-based flexible humidity sensor sensing mechanism in terms of chemical adsorption, physical adsorption, and capillary condensation mechanisms.

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PAL, U., N. MORALES-FLORES et E. RUBIO-ROSAS. « Effect of Nb Doping on Morphology, Optical and Magnetic Behaviors of Ultrasonically Grown Zno Nanostructures ». Material Science Research India 14, n^o 2 (28 septembre 2017) : 79–88. http://dx.doi.org/10.13005/msri/140201.

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ZnO nanostructures containing doped with different atom % of Nb are fabricated through ultrasound assisted hydrolysis in water. Effects of Nd incorporation on the structure, morphology, defect structure, optical, and magnetic behaviors of the nanostructures have been studied utilizing X-ray diffraction, scanning electron microscopy, photoluminescence spectroscopy and magnetometry. We demonstrate that while Nb incorporation in ZnO nanostructures drastically modify their morphology and crystallinity, it does not affect the band gap energy of of ZnO significantly. While Nb incorporation in small concentration creates higher oxygen vacancy related defects in ZnO nanostructures, which are responsible for their visible emissions, incorporation of Nb in higher concentration reduces those defect structures from the band gap of the nanostructures. While oxygen vacancies have been frequently associated to the ferromagnetic behavior of ZnO nanostructures, our results indicate that a mere presence of oxygen vacancy in Nb-doped ZnO nanostructure does not guaranty their ferromagnetic behavior.

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Naumenko, K. S., A. I. Ievtushenko, V. A. Karpyna, O. I. Bykov et L. A. Myroniuk. « The Effect of Ag-Doping on the Cytotoxicity of ZnO Nanostructures Grown on Ag/Si Substrates by APMOCVD ». Mikrobiolohichnyi Zhurnal 84, n^o 2 (28 novembre 2022) : 47–56. http://dx.doi.org/10.15407/microbiolj84.02.047.

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The search and development of new nanostructures and nanomaterials are very important for the progress of nanotechnology and modern microbiology. Due to the unique properties of silver and zinc oxide, these nanoparticles are the optimal basis for creating nanostructures with potential antiviral activity. An important issue in these studies is the establishment of cytotoxicity of these nanoparticles and their composites. Aim. To define the influence of substrate temperature and Ag concentration in ZnO lattice on the microstructure and cytotoxicity of zinc oxide nanostructures. Methods. Pure and Ag-doped ZnO nanostructures were grown on Ag/Si substrates by atmospheric pressure metalorganic chemical vapor deposition method using a mixture of zinc acetylacetonate and silver acetylacetonate powders as a precursor. Argentum thin films were deposited on Si substrates by a thermal evaporation method. MTT-assay was used for the analysis of MDBK and MDCK cell viability in the definition of zinc oxide nanostructure cytotoxicity. Results. Ag-doped zinc oxide nanostructures were grown and characterized by X-ray diff raction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. It was found that Si substrate and pure zinc oxide do not inhibit the cell viability of both epithelial cultures whereas Ag-doped ZnO nanostructures inhibit the cell viability because of all-time exposure in a sample without dilution. The cytotoxic effect was not observed at higher dilutions for Ag-doped zinc oxide nanostructures. Conclusions. The investigation of the effect of Ag-doping on the morphology and cytotoxicity of zinc oxide nanostructures is very important for implementing zinc oxide nanostructures into the current optoelectronics and photocatalysis.

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Bahari, Ali, Masoud Ebrahimzadeh et Reza Gholipur. « Structural and electrical properties of zirconium doped yttrium oxide nanostructures ». International Journal of Modern Physics B 28, n^o 16 (13 mai 2014) : 1450102. http://dx.doi.org/10.1142/s0217979214501021.

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A synthetic process for the formation of Zr x Y 1-x O y nanostructures is demonstrated by the reaction of yttrium nitrate hexahydrate with zirconium propoxide. The reactions are carried out at temperature 60°C and pressure 0.1 MPa. The energy dispersive X-ray (EDX) spectroscopy measurements confirm formation of Zr x Y 1-x O y nanostructures and the presence of carbonate and hydroxide species which are removed after high temperature anneals. It was found that the oxygen pressure during synthesis plays a determinant role on the structural properties of the nanostructure. This effect is further studied by atomic force microscopy (AFM) measurements and scanning electron microscope (SEM), which showed the formation of an isotopically organized structure. X-ray diffraction (XRD) measurement reveals that these changes in the nanostructural efficiency are associated with structural and compositional changes among the substrate. The dielectric constant as measured by the capacitance–voltage (C–V) technique is estimated to be around 39.05. C–V measurements taken at 1 MHz show the maximum capacitance for the Zr 0.05 Y 0.95 O y film. The leakage current densities were below 10-5 A/cm2 for the Zr 0.05 Y 0.95 O y film.

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R.W. Ahmad, W., M. H. Mamat, A. S. Zoolfakar, Z. Khusaimi, M. M. Yusof, A. S. Ismail, S. A. Saidi et M. Rusop. « The Effects of Sn-Doping on a-Fe2O3 Nanostructures Properties ». International Journal of Engineering & ; Technology 7, n^o 3.11 (21 juillet 2018) : 34. http://dx.doi.org/10.14419/ijet.v7i3.11.15925.

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In this study, undoped and Sn-doped hematite (α-Fe2O3) nanostructures with variation of Sn (0.5, 1, 2, 3 at. %) were deposited on fluorine doped tin oxide (FTO) coated glass substrate using sonicated immersion method. The effect of Sn-dopant on structural and crystallinity properties were investigated by characterizing FESEM and XRD respectively, while the optical properties were measured by UV-Vis-NIR spectrometer. The surface morphologies from FESEM have shown that the hematite nanostructures were grown uniformly in all samples. However, as the dopant atomic percentage increases, the amount of hematite nanostructure being grown on the FTO decreases. Results demonstrated that the amount of Sn-doping was undoubtedly influence the structural, optical and electrical properties of hematite nanostructures.

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Vysikaylo, P. I. « Quantum Size Effects Arising from Nanocomposites Physical Doping with Nanostructures Having High Electron Affinit ». Herald of the Bauman Moscow State Technical University. Series Natural Sciences, n^o 3 (96) (juin 2021) : 150–75. http://dx.doi.org/10.18698/1812-3368-2021-3-150-175.

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This article considers main problems in application of nanostructured materials in high technologies. Theoretical development and experimental verification of methods for creating and studying the properties of physically doped materials with spatially inhomogeneous structure on micro and nanometer scale are proposed. Results of studying 11 quantum size effects exposed to nanocomposites physical doping with nanostructures with high electron affinity are presented. Theoretical and available experimental data were compared in regard to creation of nanostructured materials, including those with increased strength and wear resistance, inhomogeneous at the nanoscale and physically doped with nanostructures, i.e., quantum traps for free electrons. Solving these problems makes it possible to create new nanostructured materials, investigate their varying physical properties, design, manufacture and operate devices and instruments with new technical and functional capabilities, including those used in the nuclear industry. Nanocrystalline structures, as well as composite multiphase materials and coatings properties could be controlled by changing concentrations of the free carbon nanostructures there. It was found out that carbon nanostructures in the composite material significantly improve impact strength, microhardness, luminescence characteristics, temperature resistance and conductivity up to 10 orders of magnitude, and expand the range of such components’ possible applications in comparison with pure materials, for example, copper, aluminum, transition metal carbides, luminophores, semiconductors (thermoelectric) and silicone (siloxane, polysiloxane, organosilicon) compounds

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Wang, Jyh-Liang, Po-Yu Yang, Tsang-Yen Hsieh, Chuan-Chou Hwang et Miin-Horng Juang. « pH-Sensing Characteristics of Hydrothermal Al-Doped ZnO Nanostructures ». Journal of Nanomaterials 2013 (2013) : 1–7. http://dx.doi.org/10.1155/2013/152079.

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Highly sensitive and stable pH-sensing properties of an extended-gate field-effect transistor (EGFET) based on the aluminum-doped ZnO (AZO) nanostructures have been demonstrated. The AZO nanostructures with different Al concentrations were synthesized on AZO/glass substrate via a simple hydrothermal growth method at 85°C. The AZO sensing nanostructures were connected with the metal-oxide-semiconductor field-effect transistor (MOSFET). Afterwards, the current-voltage (I-V) characteristics and the sensing properties of the pH-EGFET sensors were obtained in different buffer solutions, respectively. As a result, the pH-sensing characteristics of AZO nanostructured pH-EGFET sensors with Al dosage of 3 at.% can exhibit the higher sensitivity of 57.95 mV/pH, the larger linearity of 0.9998, the smaller deviation of 0.023 in linearity, the lower drift rate of 1.27 mV/hour, and the lower threshold voltage of 1.32 V with a wider sensing range (pH 1 ~ pH 13). Hence, the outstanding stability and durability of AZO nanostructured ionic EGFET sensors are attractive for the electrochemical application of flexible and disposable biosensor.

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Ramadan, Rehab, et Raúl J. Martín-Palma. « The Impact of Nanostructured Silicon and Hybrid Materials on the Thermoelectric Performance of Thermoelectric Devices : Review ». Energies 15, n^o 15 (24 juillet 2022) : 5363. http://dx.doi.org/10.3390/en15155363.

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Nanostructured materials remarkably improve the overall properties of thermoelectric devices, mainly due to the increase in the surface-to-volume ratio. This behavior is attributed to an increased number of scattered phonons at the interfaces and boundaries of the nanostructures. Among many other materials, nanostructured Si was used to expand the power generation compared to bulk crystalline Si, which leads to a reduction in thermal conductivity. However, the use of nanostructured Si leads to a reduction in the electrical conductivity due to the formation of low dimensional features in the heavily doped Si regions. Accordingly, the fabrication of hybrid nanostructures based on nanostructured Si and other different nanostructured materials constitutes another strategy to combine a reduction in the thermal conductivity while keeping the good electrical conduction properties. This review deals with the properties of Si-based thermoelectric devices modified by different nanostructures and hybrid nanostructured materials.

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Skobeeva, V. M., V. A. Smyntyna, M. I. Kiose et N. V. Malushin. « INCREASING THE PHOTOLUMINESCENCE EFFICIENCY OF CdS NC GROWN IN A GELATINOUS ENVIRONMENT ». Sensor Electronics and Microsystem Technologies 18, n^o 1 (31 mars 2021) : 10–19. http://dx.doi.org/10.18524/1815-7459.2021.1.227406.

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The optical and luminescent properties of nanostructures of CdS / ZnS QDs and CdS QDs doped with lithium, obtained by the sol-gel technology in an aqueous solution of gelatin, have been studied. It was determined from the optical absorption spectra of the CdS / ZnS QD nanostructures that the thickness of the shell layer corresponds to the thickness of one ZnS monolayer. The luminescence spectra revealed a significant increase in the intensity of luminescence nanostructure. The absorption spectra of undoped and doped CdS NCs coincide, which indicates that there is no change in the NC size and the absence of the formation of a lithium-sulfur compound. The luminescence spectra of lithium-doped QDs demonstrate an increase in the luminescence intensity, which is associated with the passivation of surface states.

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Wang, Chih-Chiang, Chia-Lun Lu, Fuh-Sheng Shieu et Han C. Shih. « Structure and Photoluminescence Properties of Thermally Synthesized V2O5 and Al-Doped V2O5 Nanostructures ». Materials 14, n^o 2 (13 janvier 2021) : 359. http://dx.doi.org/10.3390/ma14020359.

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Al-free and Al-doped V2O5 nanostructures were synthesized by a thermal-chemical vapor deposition (CVD) process on Si(100) at 850 °C under 1.2 × 10−1 Torr via a vapor-solid (V-S) mechanism. X-ray diffraction (XRD), Raman, and high-resolution transmission electron microscopy (HRTEM) confirmed a typical orthorhombic V2O5 with the growth direction along [110]-direction of both nanostructures. Metallic Al, rather than Al3+-ion, was detected by X-ray photoelectron spectroscopy (XPS), affected the V2O5 crystallinity. The photoluminescence intensity of V2O5 nanostructure at 1.77 and 1.94 eV decreased with the increasing Al-dopant by about 61.6% and 59.9%, attributing to the metallic Al intercalated between the V2O5-layers and/or filled in the oxygen vacancies, which behaved as electron sinks. Thus the Al-doped V2O5 nanostructure shows the potential applications in smart windows and the electrodic material in a Li-ion battery.

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Mishjil, Khudheir A., M. S. Othman, Ali H. Abdulsada, Hayfa G. Rashid et Nadir F. Habubi. « Effect of Mg doping on the optical properties of nanostructures CdO Thin film ». Journal of Physics : Conference Series 2322, n^o 1 (1 août 2022) : 012089. http://dx.doi.org/10.1088/1742-6596/2322/1/012089.

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Abstract The performance of first principles computations of nanostructured CdO and Cdo:Mg grown by spray pyrolysis method (SPM) was studied, using density functional theory (DFT)). The structural and optical behaviour with XRD and ultraviolet visible spectroscopy. DFT displayed that Cd32O32 cluster and doped magnesium have cubic with rock salt structures. The optical bandgap of nanostructure films were obtained, while theoretically calculated for Mg-doped CdO cubic structures. The optical data displayed that the magnesium doped increase optical energy gap. Moreover, Optical results displayed that reflectivity of the nanostructure films varied from (400–900 nm) range with doping. While experimental transmittance was increased about 55% for 4% and decreased to 48% for 8% concentrations.

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Cruz-Acuña, Melissa, Sonia Bailón-Ruiz, Carlos R. Marti-Figueroa, Ricardo Cruz-Acuña et Oscar J. Perales-Pérez. « Synthesis, Characterization and Evaluation of the Cytotoxicity of Ni-Doped Zn(Se,S) Quantum Dots ». Journal of Nanomaterials 2015 (2015) : 1–8. http://dx.doi.org/10.1155/2015/702391.

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Quantum dots (QDs) are semiconductor nanocrystals with desirable optical properties for biological applications, such as bioimaging and drug delivery. However, the potential toxicity of these nanostructures in biological systems limits their application. The present work is focused on the synthesis, characterization, and evaluation of the toxicity of water-stable Ni-doped Zn(Se,S) QDs. Also, the study of nondoped nanostructures was included for comparison purposes. Ni-doped nanostructures were produced from zinc chloride and selenide aqueous solutions in presence of 3-mercaptopropionic acid and Ni molar concentration of 0.001 M. In order to evaluate the potential cytoxicity of these doped nanostructures, human pancreatic carcinoma cells (PANC-1) were used as model. The cell viability was monitored in presence of Ni-doped Zn(Se,S) QDs at concentrations ranging from 0 μg/mL to 500 μg/mL and light excited Ni-doped Zn(Se,S) nanostructures were evaluated at 50 μg/mL. Results suggested that Ni-doped Zn(Se,S) nanostructures were completely safe to PANC-1 when concentrations from 0 μg/mL to 500 μg/mL were used, whereas non-doped nanostructures evidenced toxicity at concentrations higher than 200 μg/mL. Also, Ni-doped Zn(Se,S) QDs under light excitation do not evidence toxicity to PANC-1. These findings suggest strongly that Zn(Se,S) nanostructures doped with nickel could be used in a safe manner in light-driving biological applications and drug delivery.

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Al-Azri, Khalifa, Roslan Md Nor, Yusoff Mohd Amin et Majid S. Al-Ruqeishi. « Comparative Study of P-Doped and Undoped ZnO Nanostructures Using Thermal Evaporation and Vapor Transport Method ». Advanced Materials Research 667 (mars 2013) : 74–79. http://dx.doi.org/10.4028/www.scientific.net/amr.667.74.

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We report the synthesis of phosphorus-doped (P-doped) and undoped ZnO nanostructures using a thermal evaporation and vapor transport on Si(100) substrate without any catalyst and at atmospheric argon pressure. The structural and optical properties of P-doped ZnO nanostructures and undoped ZnO nanostructures have been extensively investigated using filed emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and Photoluminescence (PL). FESEM observation reveals that the morphology of ZnO nanostructures was changed from a hexagonal-like shape to a spherical shape when doping with P. While, XRD results indicate that P-doped ZnO nanostructures lost the (002) orientation preference and became randomly oriented. In addition, shifting of (002) diffraction peak has been found due to the incorporation of P into ZnO. Room temperature (PL) spectrum of P-doped ZnO nanostructures shows a high efficiency of green emission which was attributed to the presence of phosphorus atoms in the ZnO nanostructures.

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Stetsyk, N. V. « Luminescence effects in Ag-doped cadmium bromide layered nanostructures ». Functional materials 21, n^o 4 (30 décembre 2014) : 379–82. http://dx.doi.org/10.15407/fm21.04.379.

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Yoon, Sang-Hyeok, et Kyo-Seon Kim. « Doping Mo on Tungsten Oxide Thin Film and Photoelectrochemical Measurement ». Journal of Nanoscience and Nanotechnology 21, n^o 9 (1 septembre 2021) : 4813–17. http://dx.doi.org/10.1166/jnn.2021.19256.

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Tungsten oxide (WO3) is semiconductor material which can be used for various applications. Especially, one-dimensional (1-D) nanostructured WO3 shows the high photoelectrochemical (PEC) performance due to high surface area and short transport route of electron–hole pair. The flame vapor deposition (FVD) process is an efficient and economical method for preparation of the 1-D nanos-tructured WO3 thin film. Molybdenum doping is a well-known method to improve the PEC performance of WO3 by reducing band gap and increasing electrical property. In this study, we prepared the 1-D WO3 nanostructures doped with Mo by FVD single step process. We confirmed that Mo was successfully doped on WO3 without changing significantly the original nanostructure, crystal structure and chemical bonding state of WO3 thin film. As a result of PEC measurement, the pho-tocurrent densities of WO3 thin film with Mo doping were higher by about 1.4 to 2 times (for applied voltage above 0.7 V vs. SCE) than those without Mo doping.

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Eom, Seungyong, Jinjoo Jung et Do Hyung Kim. « One-Pot Synthesis of Nanostructured Ni@Ni(OH)2 and Co-Doped Ni@Ni(OH)2 via Chemical Reduction Method for Supercapacitor Applications ». Materials 16, n^o 1 (30 décembre 2022) : 380. http://dx.doi.org/10.3390/ma16010380.

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Crystalline Ni@Ni(OH)2 (cNNH) and Co-doped cNNH were obtained via a simple one-pot hydrothermal synthesis using a modified chemical reduction method. The effect of each reagent on the synthesis of the nanostructures was investigated concerning the presence or absence of each reagent. The detailed morphology shows that both nanostructures consist of a Ni core and Ni(OH)2 shell layer (~5 nm). Co-doping influences the morphology and suppresses the particle agglomeration of cNNH. Co-doped cNNH showed a specific capacitance of 1238 F g−1 at 1 A g−1 and a capacitance retention of 76%, which are significantly higher than those of cNNH. The enhanced performance of the co-doped cNNH is attributed to the reduced path length of the electrons caused by the decrease in the size of the nanostructure and the increased conductivity due to Co ions substituting Ni ions. The reported synthesis method and electrochemical behaviors of cNNH and Co-doped cNNH affirm their potential as electrochemically active materials for supercapacitor applications.

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Kaphle, Amrit, Travis Reed, Allen Apblett et Parameswar Hari. « Doping Efficiency in Cobalt-Doped ZnO Nanostructured Materials ». Journal of Nanomaterials 2019 (24 avril 2019) : 1–13. http://dx.doi.org/10.1155/2019/7034620.

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Nanostructured ZnO thin films doped with cobalt from 5% to 20% were grown on glass substrates by a low-temperature chemical bath deposition (CBD) technique. We compared the doping efficiency of incorporating cobalt in ZnO nanostructured samples doped with cobalt via cobalt nitrate and cobalt chloride. The concentration of cobalt incorporated into the ZnO matrix was precisely determined using inductively coupled plasma mass spectroscopy (ICP-MS). Scanning electron microscopy (SEM) images showed that only at a 0.1 M ratio of the precursor solutions in CBD using cobalt nitrate as a dopant, the morphology of ZnO yielded hexagonally shaped nanorods. At a 1 M ratio of the precursor solutions, SEM images showed that the morphology of ZnO was nanoplatelets at all doping levels, irrespective of the doping method used. The synthesized nanostructures retained the wurtzite hexagonal structure only at 0.1 M precursor solution using cobalt nitrate doping, which was confirmed by X-ray diffraction (XRD) studies. In cobalt-doped samples using cobalt chloride as a dopant, XRD analysis confirmed the formation of a Simonkolleite structure. At 300°C, the Simonkolleite structure was converted to a wurtzite structure without changing the morphology. Electrical conductivity measurements at 300 K showed that ZnO nanorods doped with cobalt using cobalt nitrate yielded the lowest resistivity. The molarity of the precursor solution and dopant was found to have a substantial impact on the morphology and doping efficiency of the ZnO nanostructures.

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Pacifici, D., G. Franzò, F. Iacona, S. Boninelli, A. Irrera, M. Miritello et F. Priolo. « Er doped Si nanostructures ». Materials Science and Engineering : B 105, n^o 1-3 (décembre 2003) : 197–204. http://dx.doi.org/10.1016/j.mseb.2003.08.045.

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Quandt, Alexander, Cem Özdoğan, Jens Kunstmann et Holger Fehske. « Boron doped graphene nanostructures ». physica status solidi (b) 245, n^o 10 (21 août 2008) : 2077–81. http://dx.doi.org/10.1002/pssb.200879559.

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Butusov, Leonid A., Galina K. Chudinova, Margarita V. Kochneva, Vladimir V. Kurilkin, Tatyana F. Sheshko, Alexandra Shulga, Indira A. Hayrullina et Oleg S. Kudryavtsev. « Fluorescence Properties of Tb-Doped ZnO Porous Network Thin Film Grown on Monocrystalline Silicon Substrate ». Materials Science Forum 934 (octobre 2018) : 3–7. http://dx.doi.org/10.4028/www.scientific.net/msf.934.3.

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This research presents a new perspective on optical biosensors based on zinc oxide nanoparticles. The widely known and successfully applied nanostructured material is modified by the dopant - the green phosphor Terbium, which embedded in the structure of zinc oxide and makes a significant contribution to the fluorescent response of the material in both the UV and visible spectral regions. The effect of various dopant concentrations on the fluorescence of nanostructures was studied; the nanostructures were examined by SEM.

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Bai, Xiaoyan, Tianqi Cao, Tianyu Xia, Chenxiao Wu, Menglin Feng, Xinru Li, Ziqing Mei et al. « MoS2/NiSe2/rGO Multiple-Interfaced Sandwich-like Nanostructures as Efficient Electrocatalysts for Overall Water Splitting ». Nanomaterials 13, n^o 4 (16 février 2023) : 752. http://dx.doi.org/10.3390/nano13040752.

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Constructing a heterogeneous interface using different components is one of the effective measures to achieve the bifunctionality of nanocatalysts, while synergistic interactions between multiple interfaces can further optimize the performance of single-interface nanocatalysts. The non-precious metal nanocatalysts MoS2/NiSe2/reduced graphene oxide (rGO) bilayer sandwich-like nanostructure with multiple well-defined interfaces is prepared by a simple hydrothermal method. MoS2 and rGO are layered nanostructures with clear boundaries, and the NiSe2 nanoparticles with uniform size are sandwiched between both layered nanostructures. This multiple-interfaced sandwich-like nanostructure is prominent in catalytic water splitting with low overpotential for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) and almost no degradation in performance after a 20 h long-term reaction. In order to simulate the actual overall water splitting process, the prepared nanostructures are assembled into MoS2/NiSe2/rGO||MoS2/NiSe2/rGO modified two-electrode system, whose overpotential is only 1.52 mV, even exceeded that of noble metal nanocatalyst (Pt/C||RuO2~1.63 mV). This work provides a feasible idea for constructing multi-interface bifunctional electrocatalysts using nanoparticle-doped bilayer-like nanostructures.

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Thakur, Deepika, Anshu Sharma, Abhishek Awasthi, Dharmender Singh Rana, Dilbag Singh, Sadanand Pandey et Sourbh Thakur. « Manganese-Doped Zinc Oxide Nanostructures as Potential Scaffold for Photocatalytic and Fluorescence Sensing Applications ». Chemosensors 8, n^o 4 (29 novembre 2020) : 120. http://dx.doi.org/10.3390/chemosensors8040120.

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Herein, we report the photocatalytic and fluorescence sensing applications of manganese-doped zinc oxide nanostructures synthesized by a solution combustion technique, using zinc nitrate as an oxidizer and urea as a fuel. The synthesized Mn-doped ZnO nanostructures have been analyzed in terms of their surface morphology, phase composition, elemental analysis, and optical properties with the help of scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and UV-Visible (UV-Vis) spectroscopy. A careful observation of the SEM micrograph reveals that the synthesized material was porous and grown in very high density. Due to a well-defined porous structure, the Mn-doped ZnO nanostructures can be used for the detection of ciprofloxacin, which was found to exhibit a significantly low limit of detection (LOD) value i.e., 10.05 µM. The synthesized Mn-doped ZnO nanostructures have been further analyzed for interfering studies, which reveals that the synthesized sensor material possesses very good selectivity toward ciprofloxacin, as it detects selectively even in the presence of other molecules. The synthesized Mn-doped ZnO nanostructures have been further analyzed for the photodegradation of methyl orange (MO) dye. The experimental results reveal that Mn-doped ZnO behaves as an efficient photocatalyst. The 85% degradation of MO has been achieved in 75 min using 0.15 g of Mn-doped ZnO nanostructures. The observed results clearly confirmed that the synthesized Mn-dopedZnO nanostructures are a potential scaffold for the fabrication of sensitive and robust chemical sensors as well as an efficient photocatalyst.

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Vlaskina, S. I. « Nanostructures in lightly doped silicon carbide crystals with polytypic defects ». Semiconductor Physics Quantum Electronics and Optoelectronics 17, n^o 2 (30 juin 2014) : 155–59. http://dx.doi.org/10.15407/spqeo17.02.155.

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Sumarti, Sumarti, Iwantono Iwantono et Awitdrus Awitdrus. « PENGARUH PENAMBAHAN LOGAM TRANSISI NIKEL TERHADAP SIFAT FISIS NANOROD ZnO ». Komunikasi Fisika Indonesia 17, n^o 3 (30 novembre 2020) : 155. http://dx.doi.org/10.31258/jkfi.17.3.155-159.

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Nickel-doped ZnO nanostructures have been successfully grown using seed mediated hydrothermal method. The growth of ZnO nanostructures has been done by concentration of the Ni-doped solution, is 8 mM with the growth temperature of 90°C in 7 hours. The grown ZnO nanostructures were characterized by using UV-Vis Spectroscopy, FESEM, and XRD. The UV-Vis spectra of the samples showed that the ZnO nanorod is hexagonal in shape with a strong absorption occured in the wavelength range of 300-380 nm. The FESEM images showed that geometrical shape of Ni-doped ZnO nanostructures are nanorod with a hexagonal and nanoflower faced shapes. XRD patterns observed show five diffraction peaks at 2θ: 32,09°; 34,76°; 36,65°; 47,95° and 56,97° for Ni doped ZnO nanostructures with crystal orientation of (100), (002), (101), (102) and (110) respectively. The strongest line was found in the crystal plane of (101).

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Vrithias, Nikolaos Rafael, Klytaimnistra Katsara, Lampros Papoutsakis, Vassilis M. Papadakis, Zacharias Viskadourakis, Ioannis N. Remediakis et George Kenanakis. « Three-Dimensional-Printed Photocatalytic Sponges Decorated with Mn-Doped ZnO Nanoparticles ». Materials 16, n^o 16 (18 août 2023) : 5672. http://dx.doi.org/10.3390/ma16165672.

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The present work reports on the fabrication of high-density polyethylene sponges, decorated with Mn-doped ZnO nanostructures. The sponges were developed utilizing three-dimensional printing technology, while Mn-doped ZnO nanostructures, with varying doping levels, were grown at mild temperatures. The nanostructures were fully characterized by means of scanning electron microscopy, X-ray diffraction, and Raman spectroscopy, revealing the existence of Mn doping. Moreover, their photocatalytic properties were investigated using the degradation/decolorization of a commercially available liquid laundry detergent, based on synthetic, less foaming ingredients, under UV irradiation. The Mn-doped ZnO nanostructures show better photocatalytic activity at higher doping levels. This study demonstrates that it is possible to achieve the adequate degradation of a typical detergent solution in water by means of low-cost and environmentally friendly approaches, while Mn-doped ZnO/HDPE nanostructures are good candidates for real environmental applications.

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Bharti, Dhiraj Kumar, Rajni Verma, Sonam Rani, Daksh Agarwal, Sonali Mehra, Amit Kumar Gangwar, Bipin Kumar Gupta, Nidhi Singh et Avanish Kumar Srivastava. « Synthesis and Characterization of Highly Crystalline Bi-Functional Mn-Doped Zn2SiO4 Nanostructures by Low-Cost Sol–Gel Process ». Nanomaterials 13, n^o 3 (29 janvier 2023) : 538. http://dx.doi.org/10.3390/nano13030538.

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Herein, we demonstrate a process for the synthesis of a highly crystalline bi-functional manganese (Mn)-doped zinc silicate (Zn2SiO4) nanostructures using a low-cost sol–gel route followed by solid state reaction method. Structural and morphological characterizations of Mn-doped Zn2SiO4 with variable doping concentration of 0.03, 0.05, 0.1, 0.2, 0.5, 1.0, and 2.0 wt% were investigated by using X-ray diffraction and high-resolution transmission electron microscopy (HR-TEM) techniques. HR-TEM-assisted elemental mapping of the as-grown sample was conducted to confirm the presence of Mn in Zn2SiO4. Photoluminescence (PL) spectra indicated that the Mn-doped Zn2SiO4 nanostructures exhibited strong green emission at 521 nm under 259 nm excitation wavelengths. It was observed that PL intensity increased with the increase of Mn-doping concentration in Zn2SiO4 nanostructures, with no change in emission peak position. Furthermore, magnetism in doped Zn2SiO4 nanostructures was probed by static DC magnetization measurement. The observed photoluminescence and magnetic properties in Mn-doped Zn2SiO4 nanostructures are discussed in terms of structural defect/lattice strain caused by Mn doping and the Jahn–Teller effect. These bi-functional properties of as-synthesized Zn2SiO4 nanostructures provide a new platform for their potential applications towards magneto-optical and spintronic and devices areas.

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Goswami, Navendu, et Anshuman Sahai. « Structural Evolution of Nickel Doped Zinc Oxide Nanostructures ». MRS Proceedings 1551 (2013) : 47–52. http://dx.doi.org/10.1557/opl.2013.960.

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ABSTRACTIn this article, structural evolution in nickel doped zinc oxide nanostructures is reported. The ZnO nanostructures are synthesized with 1-10% of Ni doping adopting a chemical precipitation method. The undoped and doped nanostructures thus prepared, were systematically investigated employing X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM/SEM), Fourier transform infrared (FTIR) and micro-Raman spectroscopy (μRS). The identification of wurtzite phase and determination of lattice parameters of Ni doped ZnO nanocrystallites is ascertained through XRD analysis. TEM/SEM images reveal the structural alteration of ZnO with variation of Ni doping concentrations. The study of vibrational modes of nanostructures at different stages of structural transformation, as performed through FTIR and Raman spectroscopy, assist in deciphering the crucial role of Ni doping concentration in gradual evolution of nickel doped ZnO structure from nanoparticles to nanorods.

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Lu, Chao, Etienne Joulin, Howyn Tang, Hossein Pouri et Jin Zhang. « Upconversion Nanostructures Applied in Theranostic Systems ». International Journal of Molecular Sciences 23, n^o 16 (12 août 2022) : 9003. http://dx.doi.org/10.3390/ijms23169003.

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Upconversion (UC) nanostructures, which can upconvert near-infrared (NIR) light with low energy to visible or UV light with higher energy, are investigated for theranostic applications. The surface of lanthanide (Ln)-doped UC nanostructures can be modified with different functional groups and bioconjugated with biomolecules for therapeutic systems. On the other hand, organic molecular-based UC nanostructures, by using the triplet-triplet annihilation (TTA) UC mechanism, have high UC quantum yields and do not require high excitation power. In this review, the major UC mechanisms in different nanostructures have been introduced, including the Ln-doped UC mechanism and the TTA UC mechanism. The design and fabrication of Ln-doped UC nanostructures and TTA UC-based UC nanostructures for theranostic applications have been reviewed and discussed. In addition, the current progress in the application of UC nanostructures for diagnosis and therapy has been summarized, including tumor-targeted bioimaging and chemotherapy, image-guided diagnosis and phototherapy, NIR-triggered controlled drug releasing and bioimaging. We also provide insight into the development of emerging UC nanostructures in the field of theranostics.

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Wang, Xiaojing, Yi Yang, Nan Chen, Bingfa Liu et Guihua Liu. « Preparation of LaF3:Eu3+ Based Inorganic–Organic Hybrid Nanostructures via an Ion Exchange Method and Their Strong Luminescence ». Journal of Nanoscience and Nanotechnology 16, n^o 4 (1 avril 2016) : 3729–34. http://dx.doi.org/10.1166/jnn.2016.12339.

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Lanthanide doped inorganic–organic hybrid nanostructures have received much attention in recent years due to their strong luminescence sensitized by organic ligands via an energy transfer route. In this work, an ion exchange method was used to prepare Eu3+ doped LaF3 based inorganic– organic hybrid nanostructures with organic ligands. The undoped LaF3 nanoparticles were first synthesized by a hydrothermal method, and Eu3+ ions were then ion exchanged into these LaF3 nanoparticles to form the Eu3+ doped LaF3 nanoparticles, which were then used to prepare the inorganic–organic hybrid nanostructures with benzoic acid and 2-thenoyltrifluoroacetone. As a result of the luminescence sensitization, strong luminescence was observed in these inorganic–organic hybrid nanostructures, and the luminescence enhancement was over 40 times. Dependence of the luminescence of the hybrid nanostructures on the doping concentration and amount of organic ligands was studied in detail, and optimization was conducted to obtain the maximum luminescence for the hybrid nanostructures.

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Tayyaba, Shahzadi, Muhammad Waseem Ashraf, Muhammad Imran Tariq, Maham Akhlaq, Valentina Emilia Balas, Ning Wang et Marius M. Balas. « Simulation, Analysis, and Characterization of Calcium-Doped ZnO Nanostructures for Dye-Sensitized Solar Cells ». Energies 13, n^o 18 (17 septembre 2020) : 4863. http://dx.doi.org/10.3390/en13184863.

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In this research article, the authors have discussed the simulation, analysis, and characterization of calcium-doped zinc oxide (Ca-doped-ZnO) nanostructures for advanced generation solar cells. A comparative study has been performed to envisage the effect of Ca-doped ZnO nanoparticles (NP), seeded Ca-doped ZnO nanorods (NR), and unseeded Ca-doped ZnO NR as photoanodes in dye-sensitized solar cells. Simulations were performed in MATLAB fuzzy logic controller to study the effect of various structures on the overall solar cell efficiency. The simulation results show an error of less than 1% in between the simulated and calculated values. This work shows that the diameter of the seeded Ca-doped ZnO NR is greater than that of the unseeded Ca-doped ZnO NR. The incorporation of Ca in the ZnO nanostructure is confirmed using XRD graphs and an EDX spectrum. The optical band gap of the seeded substrate is 3.18 eV, which is higher compared to those of unseeded Ca-doped ZnO NR and Ca-doped ZnO NP, which are 3.16 eV and 3.13 ev, respectively. The increase in optical band gap results in the improvement of the overall solar cell efficiency of the seeded Ca-doped ZnO NR to 1.55%. The incorporation of a seed layer with Ca-doped ZnO NR increases the fill factor and the overall efficiency of dye-sensitized solar cells (DSSC).

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Wan Ahmad, Wan Rosmaria, M. H. Mamat, A. S. Zoolfakar, Z. Khusaimi, A. S. Ismail, T. N. T. Yaakub et M. Rusop. « Effect of substrate placement in schott vial to hematite properties ». Bulletin of Electrical Engineering and Informatics 8, n^o 1 (1 mars 2019) : 58–64. http://dx.doi.org/10.11591/eei.v8i1.1391.

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In the present study, hematite (α-Fe2O3) nanostructures were deposited on fluorine doped tin oxide (FTO) coated glass substrate using sonicated immersion synthesis method. The effect of FTO glass substrate placement in Schott vial during immersion process was studied on the growth of the hematite nanostructure and its properties. XRD pattern has revealed seven diffraction peaks of α-Fe2O3 for both hematite nanostructures samples attributed to polycrystalline with rhombohedral lattice structure. The surface morphologies from FESEM have shown that the hematite nanostructures were grown uniformly in both samples with FTO conductive layer facing up and down. Hematite sample with FTO facing down exhibits a smaller size of nanorod, 26.7 nm average diameter, compared to the hematite sample that FTO face up with 53.8nm average diameter. Optical properties revealed higher transmittance in the sample with FTO facing down, probably due to smaller size of nanostructure. The optical band gap energy plotted and extrapolated at 2.50eV and 2.55eV for FTO face up and FTO face down hematite samples respectively, presenting the sample with FTO face up has a lower optical bandgap energy.

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Xiu, Faxian. « Magnetic Mn-Doped Ge Nanostructures ». ISRN Condensed Matter Physics 2012 (7 mai 2012) : 1–25. http://dx.doi.org/10.5402/2012/198590.

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With the seemly limit of scaling on CMOS microelectronics fast approaching, spintronics has received enormous attention as it promises next-generation nanometric magnetoelectronic devices; particularly, the electric field control of ferromagnetic transition in dilute magnetic semiconductor (DMS) systems offers the magnetoelectronic devices a potential for low power consumption and low variability. Special attention has been given to technologically important group IV semiconductor based DMSs, with a prominent position for Mn doped Ge. In this paper, we will first review the current theoretical understanding on the ferromagnetism in MnxGe1−x DMS, pointing out the possible physics models underlying the complicated ferromagnetic behavior of MnxGe1−x. Then we carry out detailed analysis of MnxGe1−x thin films and nanostructures grown by molecular beam epitaxy. We show that with zero and one dimension quantum structures, superior magnetic properties of MnxGe1−x compared with bulk films can be obtained. More importantly, with MnxGe1−x nanostructures, such as quantum dots, we demonstrate a field controlled ferromagnetism up to 100 K. Finally we provide a prospective of the future development of ferromagnetic field effect transistors and magnetic tunneling junctions/memories using dilute and metallic MnxGe1−x dots, respectively. We also point out the bottleneck problems in these fields and rendering possible solutions to realize practical spintronic devices.

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Karar, N. « Photoluminescence from doped ZnS nanostructures ». Solid State Communications 142, n^o 5 (mai 2007) : 261–64. http://dx.doi.org/10.1016/j.ssc.2007.02.023.

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Chelikowsky, James R., M. M. G. Alemany, T.-L. Chan et G. M. Dalpian. « Computational studies of doped nanostructures ». Reports on Progress in Physics 74, n^o 4 (16 mars 2011) : 046501. http://dx.doi.org/10.1088/0034-4885/74/4/046501.

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Hsu, W. K., Y. Q. Zhu, N. Yao, S. Firth, R. J. H. Clark, H. W. Kroto et D. R. M. Walton. « Titanium-Doped Molybdenum Disulfide Nanostructures ». Advanced Functional Materials 11, n^o 1 (février 2001) : 69–74. http://dx.doi.org/10.1002/1616-3028(200102)11:1<69 ::aid-adfm69>3.0.co;2-d.

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Alshgari, Razan A., Zaheer Ahmed Ujjan, Aqeel Ahmed Shah, Muhammad Ali Bhatti, Aneela Tahira, Nek Muhammad Shaikh, Susheel Kumar et al. « ZnO Nanostructures Doped with Various Chloride Ion Concentrations for Efficient Photocatalytic Degradation of Methylene Blue in Alkaline and Acidic Media ». Molecules 27, n^o 24 (9 décembre 2022) : 8726. http://dx.doi.org/10.3390/molecules27248726.

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In this study, chloride (Cl−) ions were successfully doped into ZnO nanostructures by the solvothermal method. The effect of various Cl− concentrations on the photocatalytic activity of ZnO towards the photodegradation of methylene blue (MB) under the illumination of ultraviolet light was studied. The as-prepared Cl−-doped ZnO nanostructures were analyzed in terms of morphology, structure, composition and optical properties. XRD data revealed an average crystallite size of 23 nm, and the XRD patterns were assigned to the wurtzite structure of ZnO even after doping with Cl−. Importantly, the optical band gap of various Cl ion-doped ZnO nanostructures was successively reduced from 3.42 to 3.16 eV. The photodegradation efficiency of various Cl− ion-doped ZnO nanostructures was studied for MB in aqueous solution, and the relative performance of each Cl ion-doped ZnO sample was as follows: 20% Cl−-doped ZnO > 15% Cl−-doped ZnO > 10% Cl−-doped ZnO > 5% Cl−-doped ZnO > pristine ZnO. Furthermore, the correlation of the pH of the MB solution and each Cl ion dopant concentration was also investigated. The combined results of varying dopant levels and the effect of the pH of the MB solution on the photodegradation process verified the crucial role of Cl− ions in activating the degradation kinetics of MB. Therefore, these newly developed photocatalysts could be considered as alternative materials for practical applications such as wastewater treatment.

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González-Carrazco, A., M. Herrera-Zaldívar et U. Pal. « Studies of Point Defect Formation and Self-Compensation in Indium Doped ZnO Nanorods by STM and STS ». Journal of Nanoscience and Nanotechnology 8, n^o 12 (1 décembre 2008) : 6598–602. http://dx.doi.org/10.1166/jnn.2008.18432.

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The effect of indium doping on the point defect formation in ZnO nanostructures is studied by scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) techniques. While the incorporation of a donor dopant like indium should increase the n-type conductivity of ZnO nanostructures, it has been found that formation of VZn native acceptors in heavily doped ZnO nanostructures produces self-compensation effect, creating acceptor states in their band gap. Presence of both donor and acceptor states in heavily indium doped ZnO nanostructures are probed and identified. The mechanism of formation of such donor and acceptor states is discussed.

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He, Qinyu, Qing Hao, Xiaowei Wang, Jian Yang, Yucheng Lan, Xiao Yan, Bo Yu et al. « Nanostructured Thermoelectric Skutterudite Co1−xNixSb3 Alloys ». Journal of Nanoscience and Nanotechnology 8, n^o 8 (1 août 2008) : 4003–6. http://dx.doi.org/10.1166/jnn.2008.469.

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Nanostructured Ni-doped skutterudites Co1−xNixSb3 (with x ranging from 0.01 to 0.09) were prepared by ball milling and direct-current induced hot press. It was found that the thermal conductivity was reduced due to strong electron–phonon scattering from Ni-doping as well as phonon scattering from the increased grain boundary of the nanostructures. A maximum dimensionless figure-of-merit of 0.7 was obtained in Co0.91Ni0.09Sb3 at 525 °C.

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Millán, Brenda Carolina Pérez, César Eduardo Cea Montufar, Fabián Mendoza Hernández et Erasto Vergara Hernández. « Photoluminescence of Silver-Doped ZnO Nanostructures ». Key Engineering Materials 945 (19 mai 2023) : 11–16. http://dx.doi.org/10.4028/p-64j9qy.

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The present work reviews the results of the photoluminescence (PL) study of silver-doped ZnO nanostructures synthesized by both physical and chemical methods. ZnO is a semiconductor with a binding energy of 60 meV, which ensures efficient near-band-edge band emission at a temperature of 300K and ultraviolet emission of bulk ZnO, and ZnO has a bandgap energy of 3.37 eV at room temperature. By tuning the growth process parameters of silver-doped ZnO nanostructures, the optical properties of ZnO can be controlled for use in various optoelectronic components, biosensors, blue-emitting diodes, and even white light sensors.

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Zhai, Bao-gai, Qing-lan Ma, Long Yang et Yuan Ming Huang. « Effects of Sintering Temperature on the Morphology and Photoluminescence of Eu3+ Doped Zinc Molybdenum Oxide Hydrate ». Journal of Nanomaterials 2018 (2018) : 1–10. http://dx.doi.org/10.1155/2018/7418508.

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Synthesis of shape controlled and rare-earth doped ZnMoO4 nanostructures on a large scale with low costs is a present challenge in nanotechnology. The precursor of Eu3+ doped zinc molybdenum oxide hydrate (Zn5Mo2O11·5H2O) was synthesized at room temperature via the coprecipitation method. The influences of the sintering temperature on the microstructures and photoluminescence (PL) of the precursor were investigated by means of X-ray diffraction, scanning electron microscopy, thermal gravimetry, differential scanning calorimetry, energy dispersive X-ray spectroscopy, diffuse reflectance spectroscopy, and PL spectrophotometry. It is found that Eu3+ doped ZnMoO4 nanostructures can be derived by sintering the precursor at a relatively low temperature of about 400°C. Our results have demonstrated that Eu3+ doped ZnMoO4 nanostructures can be cost-effectively derived by sintering the precursor at a relatively low temperature.

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Kabongo, Guy L., Gugu H. Mhlongo et Mokhotjwa S. Dhlamini. « Unveiling Semiconductor Nanostructured Based Holmium-Doped ZnO : Structural, Luminescent and Room Temperature Ferromagnetic Properties ». Nanomaterials 11, n^o 10 (4 octobre 2021) : 2611. http://dx.doi.org/10.3390/nano11102611.

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This research work describes the synthesis of ZnO nanostructures doped with Ho3+ ions using a conventional sol–gel synthesis method. The nanostructured produced exhibited a wurtzite hexagonal structure in both ZnO and ZnO:Ho3+ (0.25, 0.5, 0.75 mol%) samples. The change in morphology with addition of Ho3+ dopants was observed, which was assigned to Ostwald ripening effect occurring during the nanoparticles’ growth. The photoluminescence emission properties of the doped samples revealed that Ho3+ was emitting through its electronic transitions. Moreover, reduced surface defects were observed in the Holmium doped samples whose analysis was undertaken using an X-ray Photoelectron Spectroscopy (XPS) technique. Finally, enhanced room temperature ferromagnetism (RT-FM) for Ho3+-doped ZnO (0.5 mol%) samples with a peak-to-peak line width of 452 G was detected and found to be highly correlated to the UV–VIS transmittance results.

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Navale, Shalaka C., Farid Jamali Sheini, Sandip S. Patil, Imtiaz S. Mulla, Dilip S. Joag, Mahendra A. More et Suresh W. Gosavi. « Field Emission Properties of Al-Doped ZnO Nanostructures ». Journal of Nano Research 5 (février 2009) : 231–37. http://dx.doi.org/10.4028/www.scientific.net/jnanor.5.231.

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Field emission from Al-doped ZnO nanostrcutures has been investigated in planar diode configuration under ultra high vacuum conditions. The Al-doped ZnO nanostructures were synthesized by co-precipitation method with varying aluminium concentrations. The as- synthesized product was characterized by x-ray diffraction, scanning electron microscope and energy dispersive x-ray analysis. The threshold field required to draw a current density of ~ 1 μA/cm2 was observed to be ~ 2.0 V/μm and ~ 2.3 V/μm for Al-doped ZnO nanostructures synthesized with aluminium concentrations of 1% and 3%, respectively. The Fowler- Nordheim (F-N) plots for both the specimens exhibit non-linear behaviour, which is observed to be specimen dependent. The non-linearity observed in the F-N plots has been interpreted on the basis of the theory of electron emission from semiconductor emitters. The field enhancement factors, estimated from the slope of the F-N plots, are found to be ~ 9.3 x 103 and 3.9 x 103 for 1% and 3% Al-doped ZnO emitters, respectively. The high values of the field enhancement factor suggest that the emission is from the nanostructures. The emission current stability measured at the preset value of ~ 2 μA over a period of more than three hours is found to be fairly stable. The results indicate use of Al-doped ZnO nanostructures as promising emitters for field emission based devices.

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Wu, Zhiwei, Yaguang Li, Linjie Gao, Shufang Wang et Guangsheng Fu. « Synthesis of Na-doped ZnO hollow spheres with improved photocatalytic activity for hydrogen production ». Dalton Transactions 45, n^o 27 (2016) : 11145–49. http://dx.doi.org/10.1039/c6dt02155g.

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Ahmad, Fiaz, et Asghari Maqsood. « Structural, dielectric, impedance, complex modulus, and optical study of Ni-doped Zn_(1−x)Ni_xO nanostructures at high temperatures ». Materials Research Express 8, n^o 11 (1 novembre 2021) : 115005. http://dx.doi.org/10.1088/2053-1591/ac2fcd.

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Abstract This experiment addressed the effect of Nickel-doped on the dielectric, ac conductivity, and optical properties of pure and doped Zn (1−x) Nix O (x = 0, 3 and 6%) nanostructures. The un-doped and Ni-doped ZnO nanostructures were synthesized using co-precipitation. In this paper, the frequency-dependent dielectric and the electrical conductivity of un-doped and Ni-doped Zn (1−x) Nix O nanostructures were examined at various temperatures ranging from 320 K to 460 K using an LCR meter. For the morphological and optical investigation, the prepared samples were analyzed using field emission-scanning electron microscopy (FE-SEM), and UV visible Spectroscopy was used at room temperature. The dielectric constant ( ε ′ ), dielectric loss ( ε ″ ), tangent loss (tan δ), the real as well as the imaginary part of the impedance against the frequency ranging from 100 Hz to 2 × 106 Hz that declines with increases in frequency at different temperatures ranging from 320–460 K. However, the electrical conductivity ( σ a c ) increased with the increase in frequency was examined. The ac conductivity ( σ a c ) follows Jonscher,s power law that the electrical conductivity is enhanced with increasing doping concentration. The optical transmission area also improved due to an increase in Ni-doping concentration in ZnO. The optical bandgap of pure and Ni-doped ZnO nanostructures is in the range lies 3.30–3.12 eV found that to decrease with the increase in Ni doping concentrations.

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CHONGSRI, KRISANA, KANOKTHIP BOONYARATTANAKALIN et WISANU PECHARAPA. « EFFECT OF SEEDING FILM TYPE ON MORPHOLOGY AND ELECTRICAL PROPERTIES OF Ga-DOPED ZnO NANOSTRUCTURES GROWN BY HYDROTHERMAL PROCESS ». Surface Review and Letters 25, Supp01 (décembre 2018) : 1840005. http://dx.doi.org/10.1142/s0218625x1840005x.

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In the present work, we are interested in modifying the structures and electrical properties of Ga-doped ZnO (GZO) nanostructures by incorporation of Ga and F elements into ZnO seeding films. The ZnO, Ga-doped ZnO and F-doped ZnO thin film layers were grown by sol–gel dip coating onto glass substrates. The GZO nanostructures were grown by hydrothermal method starting from zinc nitrate and gallium (III) nitrate hydrate with a crystal growth assistance using the different types of seeding film layers. The X-ray diffractometer (XRD) and field emission scanning electron microscope (FE-SEM) are observe for the crystal structures and surface morphologies of GZO nanostructures. The changes in electrical resistance of the GZO nanostructures due to the different seeding layers were analyzed by the four-point probe technique. It is shown that the structural and electrical properties are found to be affected by the types of seeding layers.

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Mandal, Santi M., Tridib K. Sinha, Ajit K. Katiyar, Subhayan Das, Mahitosh Mandal et Sudipto Ghosh. « Existence of Carbon Nanodots in Human Blood ». Journal of Nanoscience and Nanotechnology 19, n^o 11 (1 novembre 2019) : 6961–64. http://dx.doi.org/10.1166/jnn.2019.16628.

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Presence of carbon nanostructures (dots of 2–3 nm of diameter) in human blood plasma have been identified for the first time. The observed particles are N-doped carbon dots having surface active oxygen functional groups. This functionalized carbonaceous nanostructure may have been originated through catabolic processes of consumed foods and beverages. It may take part in different catalytic activities of biomolecules in cellular system necessary for normal physiological function which is unexplored yet.

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Mehrdel, Baharak, Ali Nikbakht, Azlan Abdul Aziz, Mahmood S. Jameel, Mohammed Ali Dheyab et Pegah Moradi Khaniabadi. « Upconversion lanthanide nanomaterials : basics introduction, synthesis approaches, mechanism and application in photodetector and photovoltaic devices ». Nanotechnology 33, n^o 8 (29 novembre 2021) : 082001. http://dx.doi.org/10.1088/1361-6528/ac37e3.

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Abstract Upconversion (UC) of lanthanide-doped nanostructure has the unique ability to convert low energy infrared (IR) light to high energy photons, which has significant potential for energy conversion applications. This review concisely discusses the basic concepts and fundamental theories of lanthanide nanostructures, synthesis techniques, and enhancement methods of upconversion for photovoltaic and for near-infrared (NIR) photodetector (PD) application. In addition, a few examples of lanthanide-doped nanostructures with improved performance were discussed, with particular emphasis on upconversion emission enhancement using coupling plasmon. The use of UC materials has been shown to significantly improve the NIR light-harvesting properties of photovoltaic devices and photocatalytic materials. However, the inefficiency of UC emission also prompted the need for additional modification of the optical properties of UC material. This improvement entailed the proper selection of the host matrix and optimization of the sensitizer and activator concentrations, followed by subjecting the UC material to surface-passivation, plasmonic enhancement, or doping. As expected, improving the optical properties of UC materials can lead to enhanced efficiency of PDs and photovoltaic devices.

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Gionco, Chiara, Debora Fabbri, Paola Calza et Maria Cristina Paganini. « Synthesis, Characterization, and Photocatalytic Tests of N-Doped Zinc Oxide : A New Interesting Photocatalyst ». Journal of Nanomaterials 2016 (2016) : 1–7. http://dx.doi.org/10.1155/2016/4129864.

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Fast and simple synthetic methods for the preparation of bare and N-doped zinc oxide, involving a stirring or microwave assisted process, are proposed. All samples were characterized by XRD analysis, BET, and DRS-UV-Vis spectroscopy. The photocatalytic activity of these nanostructured oxides was investigated using phenol and 2,4-dichlorophenol as model molecules under UV-A and visible light irradiation. N-doping in ZnO nanostructures provided a significant increase in phenol and 2,4-dichlorophenol degradation rate under Vis light, leading to a degradation rate higher than that obtained with bare ZnO. The release of chlorine as chloride ions from 2,4-dichlorophenol with N-doped ZnO was faster achieved as well and complete dechlorination was reached within 2 h of irradiation (N-doped ZnO) instead of 3 h (bare ZnO).

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Rozel, Petr, Darya Radziuk, Lubov Mikhnavets, Evgenij Khokhlov, Vladimir Shiripov, Iva Matolínová, Vladimír Matolín, Alexander Basaev, Nikolay Kargin et Vladimir Labunov. « Properties of Nitrogen/Silicon Doped Vertically Oriented Graphene Produced by ICP CVD Roll-to-Roll Technology ». Coatings 9, n^o 1 (19 janvier 2019) : 60. http://dx.doi.org/10.3390/coatings9010060.

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Simultaneous mass production of high quality vertically oriented graphene nanostructures and doping them by using an inductively coupled plasma chemical vapor deposition (ICP CVD) is a technological problem because little is understood about their growth mechanism over enlarged surfaces. We introduce a new method that combines the ICP CVD with roll-to-roll technology to enable the in-situ preparation of vertically oriented graphene by using propane as a precursor gas and nitrogen or silicon as dopants. This new technology enables preparation of vertically oriented graphene with distinct morphology and composition on a moving copper foil substrate at a lower cost. The technological parameters such as deposition time (1–30 min), gas partial pressure, composition of the gas mixture (propane, argon, nitrogen or silane), heating treatment (1–60 min) and temperature (350–500 °C) were varied to reveal the nanostructure growth, the evolution of its morphology and heteroatom’s intercalation by nitrogen or silicon. Unique nanostructures were examined by FE-SEM microscopy, Raman spectroscopy and energy dispersive X-Ray scattering techniques. The undoped and nitrogen- or silicon-doped nanostructures can be prepared with the full area coverage of the copper substrate on industrially manufactured surface defects. Longer deposition time (30 min, 450 °C) causes carbon amorphization and an increased fraction of sp3-hybridized carbon, leading to enlargement of vertically oriented carbonaceous nanostructures and growth of pillars.

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Articles de revues sur le sujet « Doped Nanostructures »

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