ZnO/ZnSxSe1−x/ZnSe double-shelled coaxial heterostructure: Enhanced photoelectrochemical performance and its optical properties study

2012 ◽  
Vol 101 (25) ◽  
pp. 253109 ◽  
Author(s):  
Zhenxing Wang ◽  
Hong Yin ◽  
Chao Jiang ◽  
Muhammad Safdar ◽  
Jun He
Keyword(s):  
Optical Properties ◽  
Photoelectrochemical Performance ◽  
Coaxial Heterostructure

scholarly journals Investigating the Photoelectrochemical Performance of WO3-TiO2 Nanorod Photoanodes in Water Splitting

2021 ◽  
Author(s):  
Armin Hariri ◽  
Neda Gilani ◽  
Javad Vahabzadeh Pasikhani
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Hydrogen Generation ◽  
Band Gap Energy ◽  
Pure Tio2 ◽  
High Rate ◽  
Photoelectrochemical Performance ◽  
One Pot ◽  
Gap Energy ◽  
Tio2 Nanorod

TiO2 nanorod as a superior nanostructure has attracted a lot of attention to exert in the photocatalytic and photoelectrocatlytic applications in recent years. Nevertheless, its practical usage is restricted by a number of limitations such as the large band gap energy, the low rate of photo-induced carriers generation and the high rate of charge carriers recombination. Therefore in this study, incorporation of TiO2 nanorod with WO3 is proposed as a suitable approach to overcome these defects. In this regard, WO3-TiO2 nanorod was constructed by a facile one pot hydrothermal method in two incessant steps and was then employed as a potent photoanode for photoelectrocatalytic hydrogen generation. The morphology, elemental compositions and optical properties were characterized by the FESEM, EDS and DRS analysis, respectively. Furthermore, voltammetry analyses were performed to assay the photoelectrochemical features of WO3-TiO2 nanorod. The results confirmed that the incorporation of TiO2 nanorod with WO3 not only significantly made the band gap energy narrower (from 3eV to 2eV), but also dramatically intensified the photocurrent density and photoconversion efficiency from 1mA.cm-2 to 1.8mA.cm-2 and from 0.3% to 0.45%, respectively. As a consequence of improving optical properties and photoelectrochemical features, WO3-TiO2 nanorod could generate 2.43 mmol H2 during 100 min under UV irradiation, which was 1.71 times more than hydrogen generated over pure TiO2 nanorod

Study the Effect of the Heat Treatment on the Photoelectrochemical Performance of Binary Heterostructured Photoanode Ag2S/ ZnO Nanorod Arrays in Photoelectrochemical Cells

2020 ◽  
Vol 1002 ◽  
pp. 187-199 ◽  
Author(s):  
Asla A. Al-Zahranil ◽  
Zulkarnain Zainal ◽  
Zainal Abdib Talib ◽  
Hong Ngee Lim ◽  
Araa Mebdir Holi
Keyword(s):  
Heat Treatment ◽  
Optical Properties ◽  
Annealing Temperature ◽  
Hexagonal Phase ◽  
Zno Nanorods ◽  
Photoelectrochemical Cell ◽  
Photoelectrochemical Cells ◽  
Photoelectrochemical Performance ◽  
Structural Morphology ◽  
Zno Nras

Heterostructured semiconductors are considered one of the most significant candidates for photoelectrochemical cells (PECs) water splitting because of their visible photovoltaic features. Hence, this study displayed the synthesis of Ag2S NPs/ZnO nanorods arrays (NRAs) as a function of annealing temperature in the range between 100 °C and 500 °C. The heterostructured photoanode was fabricated through two- simple steps synthesis; the first one was hydrothermal method (HT) and the second one successive ionic layer adsorption and reaction (SILAR) method. Structural morphology characteristics, chemical conformation and properties of synthesized nanostructure were studied via different characterization techniques such as field emission scanning electron microscopy (FE-SEM), X-ray diffraction spectroscopy (XRD), HR-TEM and EDX, correspondingly. The XRD results showed that the hexagonal phase of ZnO NRAs combined successfully with monoclinicAg2S nanoparticles. The optical properties throughout absorbance spectra disclosed that with increasing the annealing temperature, the absorbance edges shifted toward extended wavelength indicating considerable enhancement in the optical properties upon the heat -treatment. Additionally, Ag2S nanoparticles/ZnO NRAs was employed as a working photoanode in photoelectrochemical cell consists of three-electrodes configuration. The result showed an important improvement in the performance of photoelectrochemical cell. It was observed that Ag2S/ZnO NRAs upon annealing at 400 °C showed an impressive photocurrent density, photoconversion efficiency of 2.73 mA/cm2 and 2.33%, respectively by achieving ~8 times higher compared to ZnO NRAs (0.337 mA/cm2). Such this enhancement was attributed to the morphological structure improvement, crystallinity and optical properties enhancement of the heterostructured photoanode after the conducting annealing process.

CuBi2O4: Electronic Structure, Optical Properties, and Photoelectrochemical Performance Limitations of the Photocathode

2021 ◽  
Vol 33 (3) ◽  
pp. 934-945
Author(s):  
Jason K. Cooper ◽  
Zemin Zhang ◽  
Subhayan Roychoudhury ◽  
Chang-Ming Jiang ◽  
Sheraz Gul ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Photoelectrochemical Performance ◽  
Performance Limitations

Tuning the composition of heavy metal-free quaternary quantum dots for improved photoelectrochemical performance

2021 ◽  
Author(s):  
Cheng Liu ◽  
Xin Tong ◽  
Ali Imran Channa ◽  
Xin Li ◽  
Zhihang Long ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Quantum Dots ◽  
Optical Properties ◽  
Hydrogen Generation ◽  
Photoelectrochemical Performance ◽  
Metal Free

The optical properties of heavy metal-free quaternary CuZnInS3 QDs can be optimized by tuning the composition, which is promising for improving the efficiency of QDs-PEC hydrogen generation.

Design of objective lens for 200-kV high-resolution electron microscopes

1983 ◽  
Vol 41 ◽  
pp. 314-315
Author(s):  
K. Tsuno ◽  
T. Honda ◽  
Y. Harada ◽  
M. Naruse
Keyword(s):  
Optical Properties ◽  
Computer Technology ◽  
Axial Magnetic Field ◽  
Chromatic Aberration ◽  
Objective Lens ◽  
Resolution Electron ◽  
Correction Of Astigmatism ◽  
Three Stages ◽  
Electron Microscopes ◽  
Stage 1

Developement of computer technology provides much improvements on electron microscopy, such as simulation of images, reconstruction of images and automatic controll of microscopes (auto-focussing and auto-correction of astigmatism) and design of electron microscope lenses by using a finite element method (FEM). In this investigation, procedures for simulating the optical properties of objective lenses of HREM and the characteristics of the new lens for HREM at 200 kV are described.The process for designing the objective lens is divided into three stages. Stage 1 is the process for estimating the optical properties of the lens. Firstly, calculation by FEM is made for simulating the axial magnetic field distributions Bzc of the lens. Secondly, electron ray trajectory is numerically calculated by using Bzc. And lastly, using Bzc and ray trajectory, spherical and chromatic aberration coefficients Cs and Cc are numerically calculated. Above calculations are repeated by changing the shape of lens until! to find an optimum aberration coefficients.

Optical Properties of HVEM Accelerators

1975 ◽  
Vol 33 ◽  
pp. 180-181
Author(s):  
A. Strojnik ◽  
J.W. Scholl ◽  
V. Bevc
Keyword(s):  
Optical Properties ◽  
Electron Accelerator ◽  
Systematic Investigation ◽  
Electron Source ◽  
High Brightness ◽  
The Past ◽  
Wide Range ◽  
Optical Behavior

The electron accelerator, as inserted between the electron source (injector) and the imaging column of the HVEM, is usually a strong lens and should be optimized in order to ensure high brightness over a wide range of accelerating voltages and illuminating conditions. This is especially true in the case of the STEM where the brightness directly determines the highest resolution attainable. In the past, the optical behavior of accelerators was usually determined for a particular configuration. During the development of the accelerator for the Arizona 1 MEV STEM, systematic investigation was made of the major optical properties for a variety of electrode configurations, number of stages N, accelerating voltages, 1 and 10 MEV, and a range of injection voltages ϕ0 = 1, 3, 10, 30, 100, 300 kV).

Differential polarization imaging of sickled cells

1988 ◽  
Vol 46 ◽  
pp. 62-63
Author(s):  
Marcos F. Maestre
Keyword(s):  
Optical Properties ◽  
Theoretical Approach ◽  
Polarized Light ◽  
Polarization Microscopy ◽  
Spectroscopic Techniques ◽  
Polarization Imaging ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Microscopic Scale ◽  
Chiral Structures

Recently we have developed a form of polarization microscopy that forms images using optical properties that have previously been limited to macroscopic samples. This has given us a new window into the distribution of structure on a microscopic scale. We have coined the name differential polarization microscopy to identify the images obtained that are due to certain polarization dependent effects. Differential polarization microscopy has its origins in various spectroscopic techniques that have been used to study longer range structures in solution as well as solids. The differential scattering of circularly polarized light has been shown to be dependent on the long range chiral order, both theoretically and experimentally. The same theoretical approach was used to show that images due to differential scattering of circularly polarized light will give images dependent on chiral structures. With large helices (greater than the wavelength of light) the pitch and radius of the helix could be measured directly from these images.

A transmission electron microscopic study of structural transitions in fast ionic conductors

1987 ◽  
Vol 45 ◽  
pp. 156-157
Author(s):  
R. B. Queenan ◽  
P. K. Davies
Keyword(s):  
Optical Properties ◽  
Ionic Conduction ◽  
Recent Observation ◽  
Ionic Conductivities ◽  
Sodium Aluminate ◽  
Two Dimensions ◽  
Ionic Conductors ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Trivalent Cations

Na ß“-alumina (Na1.67Mg67Al10.33O17) is a non-stoichiometric sodium aluminate which exhibits fast ionic conduction of the Na+ ions in two dimensions. The Na+ ions can be exchanged with a variety of mono-, di-, and trivalent cations. The resulting exchanged materials also show high ionic conductivities.Considerable interest in the Na+-Nd3+-ß“-aluminas has been generated as a result of the recent observation of lasing in the pulsed and cw modes. A recent TEM investigation on a 100% exchanged Nd ß“-alumina sample found evidence for the intergrowth of two different structure types. Microdiffraction revealed an ordered phase coexisting with an apparently disordered phase, in which the cations are completely randomized in two dimensions. If an order-disorder transition is present then the cooling rates would be expected to affect the microstructures of these materials which may in turn affect the optical properties. The purpose of this work was to investigate the affect of thermal treatments upon the micro-structural and optical properties of these materials.

Practical Correction of Three Fold Astigmatism in the Philips CM TEM

1996 ◽  
Vol 54 ◽  
pp. 418-419
Author(s):  
Arno J. Bleeker ◽  
Mark H.F. Overwijk ◽  
Max T. Otten
Keyword(s):  
Optical Properties ◽  
Phase Contrast ◽  
The Other ◽  
Objective Lens ◽  
Symmetric Part ◽  
A Posteriori ◽  
Contrast Transfer Function ◽  
High Brightness ◽  
Rotationally Symmetric ◽  
Brightness Field

With the improvement of the optical properties of the modern TEM objective lenses the point resolution is pushed beyond 0.2 nm. The objective lens of the CM300 UltraTwin combines a Cs of 0. 65 mm with a Cc of 1.4 mm. At 300 kV this results in a point resolution of 0.17 nm. Together with a high-brightness field-emission gun with an energy spread of 0.8 eV the information limit is pushed down to 0.1 nm. The rotationally symmetric part of the phase contrast transfer function (pctf), whose first zero at Scherzer focus determines the point resolution, is mainly determined by the Cs and defocus. Apart from the rotationally symmetric part there is also the non-rotationally symmetric part of the pctf. Here the main contributors are not only two-fold astigmatism and beam tilt but also three-fold astigmatism. The two-fold astigmatism together with the beam tilt can be corrected in a straight-forward way using the coma-free alignment and the objective stigmator. However, this only works well when the coefficient of three-fold astigmatism is negligible compared to the other aberration coefficients. Unfortunately this is not generally the case with the modern high-resolution objective lenses. Measurements done at a CM300 SuperTwin FEG showed a three fold-astigmatism of 1100 nm which is consistent with measurements done by others. A three-fold astigmatism of 1000 nm already sinificantly influences the image at a spatial frequency corresponding to 0.2 nm which is even above the point resolution of the objective lens. In principle it is possible to correct for the three-fold astigmatism a posteriori when through-focus series are taken or when off-axis holography is employed. This is, however not possible for single images. The only possibility is then to correct for the three-fold astigmatism in the microscope by the addition of a hexapole corrector near the objective lens.

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