Optimization of Antireflective Layers of Silicon Solar Cells: Comparative Studies of the Efficiency Between Single and Double Layer at the Reference Wavelength
Alassane Diaw,
Awa Dieye,
Ousmane Ngom,
Moulaye Diagne,
Nacire Mbengue,
Oumar Absatou Niasse,
Bassirou Ba
Issue:
Volume 9, Issue 6, November 2021
Pages:
133-138
Received:
31 August 2021
Accepted:
22 September 2021
Published:
5 November 2021
Abstract: The deposition of an antireflection coating (ARC) on the front side of the solar cells allows a significant reduction of the losses by reflection. It thus allows an increase in the efficiency of the cells. Various materials are used as an antireflection layer. For our studies, we focused on the deposition of some materials as an antireflection layer on the solar cell such as SiO2, Si3N4, TiO2, Al2O3, MgF2, and studied the efficiency of the latter. A theoretical study of antireflection layers has shown that a single antireflection layer does not have as low a reflectivity as a double antireflection layer over a large wavelength range. Thus, our interest was focused on double and multiple antireflection layers. The influence of parameters such as the thickness of the layer (s) as well as the associated refractive indexes on the optical properties of the antireflective structure has been studied. It was found that there are optimal thicknesses and refractive indices for which the reflectivity of the antireflective system is almost zero over a wider or shorter range of wavelengths. The same phenomena are noted in the study of the external quantum efficiency of the solar cell with these materials.
Abstract: The deposition of an antireflection coating (ARC) on the front side of the solar cells allows a significant reduction of the losses by reflection. It thus allows an increase in the efficiency of the cells. Various materials are used as an antireflection layer. For our studies, we focused on the deposition of some materials as an antireflection laye...
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Modelling, Simulation and Investigation of Wireless Power Transfer in Square-loop Chip at UHF Band for Medical/Biomedical Charging
Akankpo Akaninyene Okon,
Adeniran Adebayo Olusakin,
Olabisi Olusegun,
Umoren Emmanuel Bassey,
Shogo Olaide Eyiwunmi
Issue:
Volume 9, Issue 6, November 2021
Pages:
139-145
Received:
8 September 2021
Accepted:
5 October 2021
Published:
27 November 2021
Abstract: Medical electronics (Implant) devices are important in daily lives of the sick patient with terminal infections. The recent discovery of wireless power transfer (WPT) technology provides a gateway for the noncontact electricity transmission for multiple gadgets and medical implantable devices such as (artificial heart, sphincter, defibrillator and electrical simulator) simultaneously. Wireless power transfer is the transfer of power between a transmitting module and a receiving module of different system. In this work, we designed, modelled and analyzed the effects of orientation, alignment as well as coupling losses of a transmitting and receiving antenna. We designed the antenna by determining the frequency of operation (f1), dielectric constant of substrate (εr), the substrate height (h), loop length, width using the fundamental mode. Simulation of the wireless power transfer system was accomplished using the electromagnetic system COMSOL Multiphysics 5.5 model at a frequency domain of 1.8MHz. The model consists of two printed square loop antenna enclosed by an air domain with perfectly matched layer (PML). The etched layer is patterned on 2mm Polytetrafluoroethylene (PTFE) board, the thickness of the copper layer used varies geometrically, but much thicker than the copper skin depth, so that it is modelled as a perfect electric conductor (PEC). Results obtained from the simulation shows a strong coupling at 0, 22.5, 45, 67.5 degrees and a hot coupling around the receiving antenna at angle 90 degrees. These results indicate the device can only be used for direct charging.
Abstract: Medical electronics (Implant) devices are important in daily lives of the sick patient with terminal infections. The recent discovery of wireless power transfer (WPT) technology provides a gateway for the noncontact electricity transmission for multiple gadgets and medical implantable devices such as (artificial heart, sphincter, defibrillator and ...
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Study of Microscope Autofocus Based on Weighted Light Intensity
Huizong Lu,
Mingliang Tu,
Junjie Wu,
Binghai Lv,
Chengwu Wang
Issue:
Volume 9, Issue 6, November 2021
Pages:
146-156
Received:
18 November 2021
Accepted:
2 December 2021
Published:
11 December 2021
Abstract: Microscopes auto focusing is critically important for a great spectrum of scientific and industrial applications. Finding the best focus position for variety of surfaces under measurement proved to be challenging. In order to provide a rapid and accurate method for microscope focusing positioning, a laser focus deviate system was employed for microscope focusing position. The relationship between focusing sensitivity and the surface under measurement was investigated. First, the laser focus deviate technique is introduced in light of characteristic parameters such as the diameter of the focused spot, the laser wavelength and the distance from the optimal focus. Then, the focusing displacement versus spot position curve fitting is performed for a smooth isotropic surface to directly locate the best focusing position. Following, it is analyzed that when applied to anisotropic and rough surfaces, the centroid of the image spot after reflection/scattering from the surface will deviate from its original light intensity distribution, thus deviate from the calculated optimal focus position and cause focusing errors. Finally, a criterion of weighted light intensity value Q is introduced to achieve fast focusing of anisotropic surfaces in combination with the laser focusing deviate technique. The experimental results show that for a 20× microscope objective system, the focusing accuracy of this focusing positioning method is 1.7 μm on smooth surfaces; and is at the micro meter level for rough surfaces. It basically meets the requirements for rapid, stable and reliable microscope auto focusing needs.
Abstract: Microscopes auto focusing is critically important for a great spectrum of scientific and industrial applications. Finding the best focus position for variety of surfaces under measurement proved to be challenging. In order to provide a rapid and accurate method for microscope focusing positioning, a laser focus deviate system was employed for micro...
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