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Electron Depleted ZnO Nanowalls based Broadband Photodetector
摘要： Pristine ZnO has been extensively reported for high responsivity UV photodetectors based applications. However, in general, its photo-response in visible and NIR region is very poor. In this article, a simple and cost-effective technique of synthesizing pristine ZnO honeycomb nanostructure based high responsivity broadband (200 nm - 950 nm) photodetector is demonstrated. The dark current of the device was found to be as low as 5.6 pA at 10 V applied bias. The maximum photo-current to dark current ratio was ~3.2 x 107 at 300 nm wavelength (measured at -10 V applied bias). The calculated linear dynamic range of the device is as high as 128.9 dB. The maximum specific photodetectivity, photoresponsivity and external quantum efficiency (@ 300 nm) calculated at -10 V bias was 2.07x1015 cm·Hz1/2·W-1, 115 A·W-1 and 47,583% respectively, which is comparable to some of the existing commercial broadband photodetectors.
关键词： Honeycomb,ZnO,Photodetector,Hydrothermal
更新于2025-09-11 14:15:04
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Efficiency Improvement of TiO <sub/>2</sub> Nanorods Electron Transport Layer Based Perovskite Solar Cells by Solvothermal Etching
摘要： The efficiency improvement of perovskite solar cells (PSCs) by solvothermal etching and/or TiCl4 treatment of TiO2 nanorod arrays (NRAs) based electron transport layer (ETL) is reported in this article. The TiO2 NRAs are explore for the ETL because of their better direct carrier transportation over other TiO2 nanostructures. The solvothermal etching of TiO2 NRAs enhances the surface-to-volume ratio of the ETL, which, in turn, enhances the power conversion efficiency (PCE) of the PSCs. All the measurements are performed at room temperature and high humid (with ～65% humidity) conditions to demonstrate the performance of the PSCs under normal environmental conditions. A noteworthy efficiency of 15.16% with an improved fill factor and short circuit current density (JSC) is achieved in the proposed PSCs under this article. The performance of the PSC is shown to improve further by exploring TiCl4 treatment of the solvothermally etched TiO2 NRs as the ETL in the device.
关键词： solar cell,solvothermal etching,TiO2 nanorods,perovskite,Hydrothermal process
更新于2025-09-11 14:15:04
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Supermagnetic Fe <sub/>3</sub> O <sub/>4</sub> -PEG nanoparticles combined with NIR laser and alternating magnetic field as potent anti-cancer agent against human ovarian cancer cells
摘要： In the present study the magnetite nanoparticles Fe3O4 capped with polyethylene glycol PEG were prepared by hydrothermal method. Syntheses bare Fe3O4, and Fe3O4-PEG were confirmed by various techniques including X-ray powder diffraction (XRD), Transmission electron microscope (TEM), Dynamic light scattering (DLS), Scanning electron microscope (SEM), and Vibrating sample magnetometer (VSM) techniques were used to examine the magnetic properties of the Fe3O4 MNPs. The bare Fe3O4 had an average size that ranged between 12-31nm while Fe3O4- PEG had a size range of 5-15 nm. The effect of bare Fe3O4 and Fe3O4-PEG on SKOV-3 cell proliferation was measured by MTT assay. The ability of bare Fe3O4 and Fe3O4-PEG in induction of apoptosis was tested using Acridine orange/ Ethedium bromide stain. Cytotoxicity effects of bare Fe3O4 and Fe3O4-PEG against SKOV-3 cells in the presence and absence of laser photo-thermal therapy and alternating magnetic field (AMF) was also assessed. The results showed that both bare Fe3O4 and Fe3O4-PEG caused inhibition of SKOV-3 cell proliferation, resulting in their programmed death. Cytotoxic activity against SKOV-3 cells increased with NIR laser irradiation, while highly increased cytotoxic activities were observed after exposure to induction heating with AMF. In addition, the toxicity of investigated nanoparticles in liver function enzymes and histological alterations for spleen, and the lungs were addressed. The findings indicated that these nanoparticles were biocompatible with liver function enzymes and no significant alterations were recorded in the spleen, and the lungs. Taken together the present data suggest that bare Fe3O4 and Fe3O4-PEG with NIR laser and AMF could be promising for photothermal therapy protocol for cancer cells.
关键词： NIR laser,Hydrothermal synthesis,SKOV-3 cells,anticancer activity,Fe3O4-PEG,AMF
更新于2025-09-11 14:15:04
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Hydrothermal Synthesis and Upconversion Properties of About 19?nm Sc2O3: Er3+, Yb3+ Nanoparticles with Detailed Investigation of the Energy Transfer Mechanism
摘要： The Sc2O3: Er3+, Yb3+ nanoparticles (NPs) with the size of about 19 nm were synthesized by a simple oleic acid-mediated hydrothermal (HT) process. X-ray diffraction (XRD), transmission electron microscopy (TEM), upconversion luminescence (UCL) spectra, and decay curves were used to characterize the resulting samples. The Sc2O3: Er3+, Yb3+ NPs made by HT method exhibit the stronger UCL, of which the red UCL are enhanced by a factor of 4, in comparison with those samples prepared by solvothermal (ST) method at the same optimized lanthanide ion concentrations. The UCL enhancement can be attributed to the reduced surface groups and longer lifetimes. Under 980 nm wavelength excitation, the decay curves of Er3+: (2H11/2, 4S3/2) → 4I15/2 and 4F9/2 → 4I15/2 emissions for Sc2O3: Er3+, Yb3+ NPs samples are both close to each other, resulting from the cross relaxation energy transfer from Er3+ to Yb3+, followed by an energy back transfer within the same Er3+-Yb3+ pair. Also, under the relatively low-power density, the slopes of the linear plots of log(I) vs. log(P) for red and green emissions are 2.5 and 2.1, implying the existence of three-photon processes. Our results indicate that Sc2O3: Er3+, Yb3+ NPs is an excellent material for achieving intense UCL with small size in the biological fields.
关键词： Hydrothermal synthesis,Upconversion,Sc2O3,Energy transfer,Er3+/Yb3+
更新于2025-09-11 14:15:04
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Synthesis, Characterization and Optimization of Hydrothermally Fabricated Binary Palladium Alloys PdNix for Use as Counter Electrode Catalysts in Dye Sensitized Solar Cells
摘要： The hydrothermal synthesis, characterization and optimization of binary palladium alloys PdNix is hereby presented in this work. Comparison of the reduction capability of the developed PdNix alloys intended for use as alternative counter electrode catalysts in dye sensitized solar cells was made relative to the standard platinum counter electrode catalyst as well as the carbon supported PdNi-rGO sample. Optimization was accomplished through varying the molar ratio of the reagents. The unsupported PdNi3 sample produced the highest catalytic e?ciency with reduction current density, peak to peak potential di?erence and charge transfer resistance of 35 mA cm?2, 0.15 mV and 0.47 ? respectively. Obtained results show that the unsupported PdNi3 alloy was catalytically more e?ective than the platinum and PdNi-rGO thus could be a viable replacement in dye sensitized solar cell counter electrodes.
关键词： alloy,dye sensitized solar cell,counter electrode,palladium,hydrothermal
更新于2025-09-11 14:15:04
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The enhanced light harvesting performance of dye-sensitized solar cells based on ZnO nanorod-TiO2 nanotube hybrid photoanodes
摘要： In this study, TiO2/ZnO hybrid nanocomposites (TZ) were fabricated by two step synthesis route for potential applications as photoanode in dye sensitized solar cells (DSSC). Titania nanotubes were grown on titanium sheets by electrochemical oxidation. ZnO nanorods were decorated with hydrothermal method by equimolar (0.1M) precursors on TiO2 nanotubes. Hydrothermal temperatures values were changed to find the optimal ZnO hydrothermal reaction temperature can dramatically enhance the decoration density to increase photo conversion efficiency. The characterization of the photoanode was reached 1.67% for hydrothermal temperature of 130 °C which is twofold performance of TZ photoanodes. The photo conversation efficiency of DSSC by TZ were decorated with hydrothermal method by equimolar (0.1M) precursors on TiO2 photoanodes was made using FE-SEM, XRD and XPS technics. The results show that, higher than that of DSSC by TiO2 nanotubes (0.81%). The improvement in photo conversation conversion efficiency can be assigned to synergetic effect in TZ photoanode, lower recombination rate and charge transfer resistance.
关键词： TiO2 nanotube array,light harvesting,hydrothermal method,Zinc oxide,DSSC
更新于2025-09-11 14:15:04
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Synthesis and improved photoluminescence of hexagonal crystals of Li <sub/>2</sub> ZrF <sub/>6</sub> :Mn <sup>4+</sup> for warm WLED application
摘要： Engineering compositions, structures, and defects can endow nanomaterials with optimized catalytic properties. Here, we report that cobalt oxide (CoOx) ultrathin nanosheets (UTNS, ～1.6 nm thick) with a large number of oxygen defects and mixed cobalt valences can be obtained through a facile one-step hydrothermal protocol. The large number of oxygen defects make the ultrathin CoOx nanosheet a superior OER catalyst with low overpotentials of 315 and 365 mV at current densities of 50 and 200 mA cm?2, respectively. The stable framework-like architectures of the UTNS further ensure their high OER activity and durability. Our method represents a facile one-step preparation of CoOx nanostructures with tunable compositions, morphologies, and defects, and thus promotes OER properties. This strategy may find its wider applicability in designing active, robust, and easy-to-obtain catalysts for OER and other electrocatalytic systems.
关键词： ultrathin nanosheets,oxygen evolution reaction,electrocatalysis,hydrothermal synthesis,cobalt oxide
更新于2025-09-11 14:15:04
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Renewable and Sustainable Composites || Methodologies for Achieving 1D ZnO Nanostructures Potential for Solar Cells
摘要： One-dimensional (1D) nanostructures are generally used to describe large aspect ratio rods, wires, belts, and tubes. The 1D ZnO nanostructures have become the focus of research owing to its unique physical and technological significance in fabricating nanoscale devices. When the radial dimension of the 1D ZnO nanostructures decreases to some lengths (e.g., the light wavelength, the mean of the free path of the phonon, Bohr radius, etc.), the effect of the quantum mechanics is definitely crucial. With the large surface-to-volume ratio and the confinement of two dimensions, 1D ZnO nanostructures possess the captivating electronic, magnetic, and optical properties. Furthermore, 1D ZnO nanostructure’s large aspect ratio, an ideal candidate for the energy transport material, can conduct the quantum particles (photons, phonons, electrons) to improve the relevant technique applications. To date, many methods have been developed to synthesize 1D ZnO nanostructures. Therefore, methodologies for achieving 1D ZnO nanostructures are expressed, and the relevant potential application for solar cells are also present to highlight the attractive property of 1D ZnO nanostructures.
关键词： hydrothermal,nanostructures,one dimensional,ZnO,solar cell,chemical vapor transport and condensation (CVTC),vapor-liquid-solid (VLS),electrochemical,metal-organic chemical vapor deposition (MOCVD),chemical vapor deposition (CVD)
更新于2025-09-11 14:15:04
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Photocatalytic inactivation of <i>Escherischia coli</i> under UV light irradiation using large surface area anatase TiO <sub/>2</sub> quantum dots
摘要： In this study, high specific surface areas (SSAs) of anatase titanium dioxide (TiO2) quantum dots (QDs) were successfully synthesized through a novel one-step microwave–hydrothermal method in rapid synthesis time (20 min) without further heat treatment. XRD analysis and HR-TEM images showed that the as-prepared TiO2 QDs of approximately 2 nm size have high crystallinity with anatase phase. Optical properties showed that the energy band gap (Eg) of as-prepared TiO2 QDs was 3.60 eV, which is higher than the standard TiO2 band gap, which might be due to the quantum size effect. Raman studies showed shifting and broadening of the peaks of TiO2 QDs due to the reduction of the crystallite size. The obtained Brunauer–Emmett–Teller specific surface area (381 m2 g?1) of TiO2 QDs is greater than the surface area (181 m2 g?1) of commercial TiO2 nanoparticles. The photocatalytic activities of TiO2 QDs were conducted by the inactivation of Escherischia coli under ultraviolet light irradiation and compared with commercially available anatase TiO2 nanoparticles. The photocatalytic inactivation ability of E. coli was estimated to be 91% at 60 μg ml?1 for TiO2 QDs, which is superior to the commercial TiO2 nanoparticles. Hence, the present study provides new insight into the rapid synthesis of TiO2 QDs without any annealing treatment to increase the absorbance of ultraviolet light for superior photocatalytic inactivation ability of E. coli.
关键词： TiO2,X-ray diffraction,quantum dots,photocatalysis,microwave–hydrothermal
更新于2025-09-11 14:15:04
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Graphene quantum dot vertical cavity surface emitting lasers
摘要： Nonzero-bandgap graphene quantum dots (GQDs) are novel optical gain materials promising for solution-processed light sources with high cost efficiency and device performance. To date, there have only been a few reports on the realization of GQDs-based lasers. Herein, we demonstrate for the first time room-temperature lasing emission with green gamut from GQDs in a vertical optical cavity composed of Ta2O5/SiO2 dielectric distributed Bragg reflectors (DBRs). The lasing is enabled by the unique design of the DBR which not only provides a wide stopband spectrally overlapping with the emission of the GQDs but also allows high transmittance of optical excitation in the UV-light region. This demonstration is a clear evidence of the use of GQDs as optical gain materials and represents an important step forward toward their potential applications in wide-gamut laser displays and projectors.
关键词： Vertical Cavity Surface Emitting Laser,Graphene Quantum Dots,Green Gap,Microwave-Assisted Hydrothermal Method,Distributed Bragg Reflectors (DBRs)
更新于2025-09-11 14:15:04