- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
ZnO and TiO2 Nanostructured Dye sensitized Solar Photovoltaic Cell
摘要： The performance of nanostructured metal oxides (ZnO and TiO2) based dye sensitized solar cells (DSSC) were investigated. Natural dye, chlorophyll extracted from fresh spinach leaves, was used as sensitizer for fabrication of the cells. ZnO was synthesized by chemical bath deposition technique.The Field emission scanning electron microscopic (FESEM) images show hexagonal patterned ZnO nano-towers of 5 μm length and ~ 1 μm diameter. TiO2 was synthesized by sol-gel method.The FESEM images show that the TiO2 nano-rods of 2 μm length and ~ 300 nm diameter.TiO2 based DSSC was possessed better efficiency of 0.27% as compare to ZnO based DSSC of 0.13%.
关键词： Diffused Reflectance Spectra,Chlorophyll dye,Dye sensitized solar cells,Chemical and sol-gel synthesis
更新于2025-09-16 10:30:52
-
[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Optical-Response Analysis of Voltage-Modulated 1.3 μm Wavelength AlGaInAs/InP Transistor Laser
摘要： Transistor Laser (TL) has multiple modulation methods by a combination of terminal connection because it has three electrical terminals unlike the laser diodes. In this report, for the voltage modulation of the TL, the light output response under a large signal voltage modulation was simulated. By considering the transient change of the current in the active layer, we succeeded in reproducing the light output having the peak in the opposite direction to the steady state observed with the actual device so far. Based on the simulation, the optimum collector-base capacitance in the actual device and the minimum required end-facet reflectance for securing a high extinction ratio were obtained.
关键词： light output response,voltage modulation,collector-base capacitance,Transistor Laser,end-facet reflectance
更新于2025-09-16 10:30:52
-
Solar Engineering of Thermal Processes, Photovoltaics and Wind || Radiation Transmission through Glazing
摘要： The transmission, reflection, and absorption of solar radiation by the various parts of a solar collector are important in determining collector performance. The transmittance, reflectance, and absorptance are functions of the incoming radiation, thickness, refractive index, and extinction coefficient of the material. Generally, the refractive index n and the extinction coefficient K of the cover material are functions of the wavelength of the radiation. However, in this chapter, all properties initially will be assumed to be independent of wavelength. This is an excellent assumption for glass, the most common solar collector cover material. Some cover materials have significant optical property variations with wavelength, and spectral dependence of properties is considered in Section 5.7. Incident solar radiation is unpolarized (or only slightly polarized). However, polarization considerations are important as radiation becomes partially polarized as it passes through collector covers.
关键词： absorptance,refractive index,solar radiation,transmittance,extinction coefficient,wavelength,reflectance,collector performance,polarization
更新于2025-09-16 10:30:52
-
Chemical Texturization Processes for Non-conventional Silicon Substrates for Silicon Heterojunction Solar Cell Applications
摘要： The present work addresses the exhaustive study of the surfaces of multicrystalline silicon wafers after being subjected to a texturization process for silicon heterojunction solar cell applications. The investigations described include the effect that the time of isotropic etching based on combinations of hydrofluoric and nitric acids has on the reflectance, the morphology of the surfaces and the surface recombination through the evolution of the implicit open-circuit voltage. The influence of previous treatments and the elimination of porous silicon or silicon oxide formed on wafer surfaces as a consequence of these texturization processes are also addressed. Textured multicrystalline silicon wafer surfaces with a good uniformity and low weighted hemispherical reflectances (23–24%) have been achieved with short etching times. These texturization processes have also been tested on upgraded metallurgical silicon wafers, resulting in weighted hemispherical reflectance values around 23%, but at the cost of the appearance of important surface defects.
关键词： Multicrystalline silicon,Reflectance,Chemical texturization,Surface morphology,Silicon heterojunction solar cells,UMG silicon
更新于2025-09-12 10:27:22
-
Feasibility of gem identification using reflectance spectra coupled with artificial intelligence
摘要： Standard traditional gem identification requires expert supervision, while sophisticated modern methods are time-consuming and expensive. In contrast, reflectance spectroscopy coupled with artificial intelligence is economical and convenient and does not require specialist supervision. This study established an artificial neural network model that consists of standard multilayered, feed-forward, and back-propagation neural networks, and obtained reflectance spectra of a transparent gem (almandine), an opaque gem (turquoise), several almandine imitations (agate, plastic, and glass), and several treated turquoise samples (dyed, impregnated, and Zachery treated) using an Analytical Spectral Devices spectrometer. The acquired spectra were used to train and test the artificial neural network model. The results show that the model can effectively discriminate between genuine and imitation gems of different classes. However, discrimination between natural and treated gems of same class is not as effective as discrimination of gems of different classes. The results suggest that an artificial neural network based on reflectance spectroscopy could serve as a useful tool for preliminary gem identification, and the advanced identification needs further training and investigation.
关键词： reflectance spectrum,artificial neural network,Artificial intelligence,gem identification
更新于2025-09-12 10:27:22
-
Hot carrier dynamics in a dispersionless plasmonic system
摘要： Hot carrier dynamics in a broadband, dispersionless, plasmonic structure are studied using pump-probe measurements with 45 fs time resolution. The results obtained by simultaneous measurement of differential transmittance and reflectance show the influence of pump generated carriers on the probe generated plasmons. The dependence of decay time on the pump fluence is linear for the interband and intraband carrier excitation near the L-symmetry point in gold. However, 1.908 eV pump excitation, which allows both interband transition at the X-symmetry point and intraband excitation at the L-symmetry point, shows quadratic dependence of decay time on the pump fluence. Degenerate pump-probe measurements at 1.55 eV, which allow L-valley intraband excitations, highlight the difference in surface (reflection) and the bulk (transmission) mechanisms. Hot carrier relaxation time is in the 1–3 ps range for different excitation energies. Rise time, governed by the plasmon to hot carrier conversion and electron-electron scattering processes, is about 200 ± 35 fs for the hot carrier and hot plasmon excitation cases that increased to about 485 ± 35 fs when the pump is resonant with the interband transition at the X-symmetry point. Results show that the hot carrier dynamics are governed by the bulk metal band structure. The dipole matrix element for each of the transitions is estimated by density matrix calculations.
关键词： pump-probe measurements,gold band structure,differential transmittance,reflectance,plasmonic system,hot carrier dynamics
更新于2025-09-12 10:27:22
-
Graphene’s photonics and optoelectronics properties – A Review
摘要： Due to its remarkable electrical and optical properties, graphene continues to receive more and more attention from researchers around the world. An excellent advantage of graphene is the possibility of controlling its charge density, and consequently, the management of its conductivity and dielectric constant, among other parameters. It is noteworthy that the control of these properties enables the obtaining of new optical/electronic devices, which would not exist, based on conventional materials. However, to work in this area of science, it is necessary a thorough knowledge regarding the electrical/optical properties of graphene. In this review paper, we show these graphene properties very well detailed.
关键词： Absorbance (78.20.-e),Conductivity (78.20.-e),Substrate (78.40.Fy),Reflectance (78.20.-e),Surface plasmons polaritons (73.20.Mf),Transmittance (78.20.-e),Dispersion relation (11.55.Fv),Dielecric constant (31.15.es)
更新于2025-09-12 10:27:22
-
Nanosecond Pulsed Laser Irradiation of Titanium Alloy Substrate: Effects of Periodic Patterned Topography on the Optical Properties of Colorizing Surfaces
摘要： Most of the current works based on surface treatments of metals by laser marking technology are focused on the modification of the color tonality of flat surfaces, or the development of specific topography features, but the combination of both processes is not usually evaluated, mainly due to the complexity of controlling the optical properties on rough surfaces. This research presents an analysis of the influence of the micro-geometrical characteristics of periodic patterned laser tracks on the chromaticity and reflectance of Ti6Al4V substrates. The samples were irradiated with an infrared nanosecond pulsed laser in air atmosphere, taking as the control parameter the scan speed of the beam. A roughness evaluation, microscopic inspection, and absorption and chromaticity examination were conducted. Although micro-crack growth was detected in an isolated case (10 mm/s), the possibility of adjusting the result color was demonstrated by controlling the heat-affected zone thickness of the textures. The results of rough/colored combined textures allow new perspectives in industrial design to open, particularly in aesthetic applications with special properties.
关键词： titanium,oxidation,reflectance,roughness,color,laser marking
更新于2025-09-12 10:27:22
-
Application of reflectance confocal microscopy to investigate the non-ablative, micro-ablative, and ablative effects of CO2 fractional laser irradiation on skin
摘要： CO2 fractional laser, as an ablative fractional laser, is commonly used in cosmetic treatment. We applied CO2 fractional laser irradiation to skin in vitro and used reflectance confocal microscopy (RCM) to image and detect the presence of any non-ablative, micro-ablative and ablative effects, in order to better understand the features of a CO2 fractional laser. In vitro irradiation of foreskin was performed using a CO2 fractional laser. Foreskin specimens were divided into 4 groups that received different amounts of irradiation energy, based on the number of irradiation passes they received: 5, 10, 15, and 20 passes, respectively. This corresponds to fluence energy of 16.3, 32.6, 48.9, 65.3 J/cm2. Immediately after irradiation, digital microscopy (DM), RCM, and histopathology were performed to observe whether the non-ablative, micro-ablative, and ablative phenomenon occurred, and the injury features of MTZs. Immediately after CO2 fractional laser irradiation, RCM and DM showed that when the numbers of passes were 5 and 10, a micro-ablative column (MAC) could not be observed or was very small. We mainly observed a thicker thermal coagulation zone (TCZ), representing non-ablative or micro-ablative effects. When the number of passes were increased to 15 and 20, the MAC was significantly enlarged and surrounded by a TCZ of medium thickness, representing ablative effects. For the first time, this study used RCM and DM to demonstrate that a CO2 fractional laser could achieve non-ablative, micro-ablative, and ablative effects on irradiated skin via different energy levels.
关键词： Microscopic treatment zone (MTZ),Non-ablative,Digital microscopy (DM),Micro-ablative,Reflectance confocal microscopy (RCM),CO2 fractional laser
更新于2025-09-12 10:27:22
-
Low reflecting hierarchically textured silicon by silver assisted chemical etching for potential solar cell application
摘要： Present study reports fabrication of silicon nanowires over micro-textured Si substrates. Silver assisted electroless chemical etching route has been adopted for fabrication of the nanowires. Influence of HF concentration on the formation kinetics has been investigated by using scanning electron microscopy. The hierarchical binary structures have been able to reduce solar weighted reflectance (SWR) to <3% in broad spectral range (300-1100 nm), from 38% SWR of the polished silicon without any additional coating. Such reduction in reflectivity is obtained for <1 μm nanowires length. It is observed that at relatively lower concentration of HF the nanowires are preferably formed only in <100> direction. However, with increase in the concentration, etching in both <100> and non-<100> directions such as <111> also occurs on the micro-pyramids of similar dimensions and results in the binary structures with slanted silicon nanowires on 3-dimansional micro-pyramids.
关键词： Nanowire,Micro-pyramid,Chemical Etching,Reflectance,Silicon Nanowire
更新于2025-09-12 10:27:22