Wavelengths Of Solar Spectrum Research Articles

Effect of gradually increasing germane flow rate during the deposition on the performance of a-SiGe:H solar cell

In this paper, we fabricated a hydrogenated amorphous silicon-germanium ( a - SiGe : H ) thin film solar cell with gradually increasing GeH 4 flow rate in order to absorb long wavelength of solar spectrum without stacked structures such as tandem or triple junctions. The thin film solar cell with the a - SiGe : H in its intrinsic layer deposited using 13.56 MHz radical-assisted/plasma-enhanced chemical vapor deposition (RA/PECVD) was characterized according to several conditions of gradually varying GeH 4 flow rate. Under AM 1.5 G conditions, open-circuit voltage (V OC ), short-circuit current density (J SC ), fill factor and efficiency have been investigated. Also, external quantum efficiency (EQE) was measured. As a result, the best value of V OC , J SC and fill factor were 0.42 V, 24.16 mA/cm2 and 0.52, respectively. Efficiency of the solar cell was up to 5.3%, and EQE in the wavelength range of 400–800 nm occupied most of photon absorption.

Performance of gerbera cultivars under different wavelengths of solar spectrum

To find out the response of potted gerbera under different light spectrum wavelengths of solarradiation was carried out. Three gerbera cultivars viz. V1 (red), V2 (pink), V3 (brick red) and seventreatments viz. L1 (full spectrum), L2 (no spectrum), L3 (cut of 380 - 750 nm wavelength), L4 (cut of620 - 750 nm wavelength), L5 (cut of 450 - 495 nm wavelength), L6 (cut of 495 - 570 nmwavelength) and L7 (cut of 570 - 590 nm wavelength) were exerted on the experiment. Among thecultivars brick red was the best one. Plants were green because they reflected 495 - 570 nmwavelengths (green band) from the visible spectrum of solar radiation. Current findings indicatedthat of 495 - 570 nm wavelengths (green band), the plants responded alike to the full spectrum. Nospectrum provided the worst result in all attributes of gerbera. Number of flower, peduncle length,peduncle diameter, flower head diameter and bending percentage were least after no spectrum in allthe treatments. All the treatments except full spectrum and of 495 - 570 nm wavelength (greenband) restricted for the entrance of the 620 - 750 nm wavelength (red band); 620 - 750 nmwavelength (red band) of light was very important for the plants. Besides, absence of 620 - 750 nmwavelengths (red band) and 450 - 495 nm wavelength (blue band) drastically hampered plantgrowth, yield and quality contributing characters. DOI: http://dx.doi.org/10.3329/jbas.v38i1.20202 Journal of Bangladesh Academy of Sciences, Vol. 38, No. 1, 27-37, 2014

High Performance ZnO-SnO2:F Nanocomposite Transparent Electrodes for Energy Applications

Enhancing the propagation length of light without sacrificing the electro-optical properties of transparent electrodes is of particular interest to solar cells for reaching higher efficiency. This can typically be achieved by nanostructured electrodes but all too often at the expense of complexity and cost-effectiveness. In this work, we demonstrate the simple and low-cost fabrication of a new type of ZnO-SnO2:F nanocomposite thin film by combining spin-coated ZnO nanoparticles on glass with fluorine-doped SnO2 thin films deposited by atmospheric spray pyrolysis. The resulting nanocomposites exhibit a dual surface morphology featuring rough ZnO-SnO2:F nanostructures along with the original smooth SnO2:F thin film. By readily modulating the surface morphology of ZnO-SnO2:F nanocomposite thin films with the initial ZnO NP surface coverage, the scattering efficiency of the incident light can remarkably be controlled over the 400-1100 nm solar spectrum wavelength range. High quality hazy ZnO-SnO2:F thin layers are therefore formed with an averaged haze factor ranging from 0.4 to 64.2% over the 400-1100 nm solar spectrum range while the sheet resistance is kept smaller than 15 Ω/sq for an average total optical transmittance close to 80%, substrate absorption and reflection included. Eventually, optical simulations using Fourier transform techniques are performed for computing the obtained haze factors and show good agreement with experimental data in the 400-1100 nm solar spectrum wavelength range. This opens up additional opportunities for further design optimization of nanoengineered transparent electrodes.

Optimization of Anti-reflection Coating for Improving the Performance of GaAs Solar Cell

The objective of this work is to reduce the front surface reflectivity of the GaAs solar cell by depositing AR-coating of appropriate thickness and refractive index material. We use MgO and ZnO film and optimize their thickness for minimum reflectivity. Results indicate that the reflectivity is reduced up to 4% for MgO film and 2% for ZnO film at solar spectrum wavelength range from 550 nm to 650 nm. The external efficiency of GaAs solar cell with AR-coating is increased by 31.53% and 33.09% for MgO and ZnO film respectively.

Optical and Structural Characterization of Nickel Coatings for Solar Collector Receivers

The development of spectrally selective materials is gaining an increasing role in solar thermal technology. The ideal spectrally selective solar absorber requires high absorbance at the solar spectrum wavelengths and low emittance at the wavelengths of thermal spectrum. Selective coating represents a promising route to improve the receiver efficiency for parabolic trough collectors (PTCs). In this work, we describe an intermediate step in the fabrication of black-chrome based solar absorbers, namely, the fabrication and characterization of nickel coatings on stainless steel substrates. Microstructural characteristics of nickel surfaces are known to favorably affect further black chrome deposition. Moreover, the high reflectivity of nickel in the thermal infrared wavelength region can be advantageously exploited for reducing thermal emission losses. Thus, this report investigates structural features and optical properties of the nickel surfaces, correlating them to coating thickness and deposition process, in the perspective to assess optimal conditions for solar absorber applications.

Nano surface two-dimensional periodic half-round grooves enhanced light absorption in silicon film solar cell

The influence of nano surface two-dimensional periodic half-round grooves on the enhancement of light absorption in silicon film solar cell is studied with the finite-difference time-domain method. The result shows that the broadband solar spectrum absorption is enhanced. The light optical absorption in Si thin-film cell is enhanced by optimizing the thickness of SiO2 anti-reflection film and the radius of half-round grooves, and the total integrated absorption of solar spectrum wavelength in a range from 300 nm to 1000 nm is about 117% greater than that of single silicon thin film.

Comprehensive light trapping study of next generation thin film solar cells

ABSTRACTLight trapping is one of the key challenges for the next generation of thin film solar cells. In this work, we have identified the distinct light trapping effects for short and long wavelength solar spectrum ranges, by investigating lighting trapping structures on both sides of Si thin film solar cells. The sub-wavelength moth-eye-like photonic front surface and multi-layer grating photonic crystal reflector on the bottom surface are studied in detail via the Finite Difference Time Domain method for its solar energy absorption characteristics. Our study reveals the drastic difference in the light trapping effects within the solar spectrum wavelength. This work may provide guidance for efficiency enhancement of next generation thin film photovoltaic cells.

Efficiency Enhancement of Organic Solar Cells Using Transparent Plasmonic Ag Nanowire Electrodes

Surface plasmon enhanced photo-current and power conversion efficiency of organic solar cells using periodic Ag nanowires as transparent electrodes are reported, as compared to the device with conventional ITO electrodes. External quantum efficiencies are enhanced about 2.5 fold around the peak solar spectrum wavelength of 560 nm, resulting in 35% overall increase in power conversion efficiency than the ITO control device under normal unpolarized light.

Relationships between aerosol optical depth and surface-layer extinction in the central part of the Upper Silesia industrial region over the period of 1983–1994

The subject of analysis is the aerosol optical depth (AOD) in the visible part of the solar spectrum ( τ vis ) (wavelength λ = 0.295 – 0.695 μ m ). Calculation of τ vis -values was based on pyrheliometric observation data performed from 1983 to 1994 at IEIA's station (Katowice-Załęże). This paper examines the dependence of τ vis and its relation to surface-layer extinction coefficient σ (Koschmider quotient of 3.912 and visibility V ) on meteorological and anthropological factors during the observation period. Knowledge of the relationship between columnar aerosol turbidity (which can be expressed by τ vis ) and σ allows a more precise and accurate estimation of the aerosol effect on the radiative composition of climate. This work offers some contributions to solving this problem. Therefore, the relations have been described in the form of mathematical/statistical models of AOD (based on “momentary” and mean seasonal values), in which meteorological (and astronomical) parameters as well as the amount of industry dust emission were used as independent variables to improve exactness and credibility in the models.

Calculation of photovoltaic characteristics and materials selection for low-band-gap cells of multi-structure solar cell system

Photovoltaic characteristics of low-band-gap cells for a high efficiency multi-structure solar cell system are calculated using a precise modeling of the absorption coefficient for direct and indirect transitions in the absorption and window layers. Taking the AlGaAs/GaAs cell as the intermediate-band-gap cell, several materials and device structures for the low-band-gap cell are investigated to give the highest conversion efficiency at one sun AM0. The materials are chosen from those currently available that can be grown by conventional growth techniques with a high enough quality and a large enough area. It is predicted for the solar spectrum wavelength region longer than 0.87 μm at one sun AM0 that the cell with In0.53Ga0.47As the absorption layer can give an efficiency of 5.84% with a perfect AR-coating and an In0.52Al0.48As window, and that the cell with In0.67Ga0.33As0.71P0.29 as the absorption layer can give an efficiency of 6.32% with a perfect AR-coating and In0.52Al0.48As window. It is shown that simpler structures with a very thin InP window layer also give similar efficiencies.

Early history of fourier transform spectroscopy

This is an attempt to explain how and why the stage was set for the appearance on the scene of Fourier transform spectroscopy (FTS) in the 1950s and not a whit before. The play begins 100 years earlier with Fizeau and Foucault who first produced high path-difference interference phenomena and used them for measuring solar spectrum wavelengths in the near IR. Next, the story unfolds with Michelson's contribution, which led to important discoveries around 1890: the hyperfine structures and widths of atomic lines. Somewhat less well known is the Rubens interferometric technique, presented in 1910, because no such striking results were ever collected; still, it represented a distinct advance over the Michelson one. What is the reason why Michelson, Rubens and Lord Rayleigh (who made no experiments himself but understood all about them) never managed to get together and propose the modern form of FTS? Part of the responsibility we must ascribe to chance; however, sufficient motivation could not be felt as long as basic noise limitations had not been understood and closely approached.

Clarification in the identification of certain lines in the infrared solar spectrum

Forty-two unidentified spectral lines in Mohler's (1955) table of infrared solar spectrum wavelengths are shown to be solar, and three of these tentatively have been identified. One line, listed by Mohler as solar or telluric, is shown to be telluric.

Atomic spectra—Their rôle in astrophysics

This paper deals with the use of atomic spectra as a connecting link between stars and atoms, illustrated by the spectrum of the Sun, our nearest star. The importance of the multiplets found from the analyses of laboratory spectra, in the identification of solar lines is exemplified by selected lines of P i, S i, Si i, Mg i, and Fe i. Solar lines identified from predicted wavelengths, calculated from the energy levels, are found among these spectra. The elements represented in the Sun only in compounds or by only one atomic line are discussed in some detail. A second revision of Rowland's Table of Solar Spectrum Wavelengths, including measured equivalent widths and revised identifications, provides an excellent example of the rôle of atomic spectra in astrophysics.

REVIEW: Revision of Rowland's Preliminary Table of Solar Spectrum Wave-Lengths with an Extension to the Present Limit of the Infra-Red by C. E. St. John, C. E. Moore, L. M. Ware, E. F. Adams, H. D. Babcock

REVIEW: Revision of Rowland's Preliminary Table of Solar Spectrum Wave-Lengths with an Extension to the Present Limit of the Infra-Red by C. E. St. John, C. E. Moore, L. M. Ware, E. F. Adams, H. D. Babcock

THE RELATIVE NUMBER OF LINES OF DIFFERENT INTENSITY IN THE SOLAR SPECTRUM

For statistical purposes, the Revision of Rowland's Preliminary Table of Solar Spectrum Wave-Lengths was divided into 45 sections containing approximately equal numbers of lines. In those sections the atomic solar lines of the various intensity classes were counted, those of intensity exceeding 3 being grouped together. All lines known to be of molecular origin, either solar or telluric, were purposely omitted in order to make the comparison with laboratory data more significant, although the large number of weak lines still unidentified in the Sun leaves some uncertainty in this regard. The total number of lines counted from I 2975 to A 10218 was 18,423. Beyond the limit of Rowland's work, A 7330, the intensity scale is necessarily somewhat different, chiefly with respect to the weakest lines. Since infra-red photography is increasingly difficult for the longer wave-lengths, lower dispersion and resolving power must be used for this region, with the resultant loss of many of the faintest lines. Published intensities of infra-red solar lines

Revision of Rowland's Preliminary Tables of Solar Spectrum Wave-Lengths

Revision of Rowland's Preliminary Tables of Solar Spectrum Wave-Lengths

VI. The ultra-violet band of ammonia, and its occurrence in the solar spectrum

A question of great interest in connection with the solar spectrum is that of the origin of the thousands of unidentified faint lines which were catalogued by Rowland in his “Preliminary Table of Solar Spectrum Wave-lengths.” Some of these lines may possibly be identical with faint lines in metallic spectra which have not yet been completely tabulated, but in view of the presence of bands of cyanogen, carbon and hydrocarbon, the possibility of the correspondence of most of them with band spectra of other substances should not be overlooked. As a contribution to this inquiry, the present investigation was undertaken primarily in order to determine whether Group P in the ultra-violet region of the solar spectrum might not be mainly due to the presence of ammonia in the absorbing atmosphere of the sun. Ammonia was already known to give a remarkable band in this region, having its position of maximum intensity near λ 3360, but it had not been investigated in sufficient detail to permit of an adequate comparison with the solar tables. Photographs have accordingly been taken with spectrographs of high resolving power for the purpose of this comparison, and, as will appear from the details which follow, it has been established that the ammonia band is certainly represented in the solar spectrum, and accounts for a considerable number of faint lines for which no other origins have been suggested.

The Situation in Regard to Rowland's Preliminary Table of Solar Spectrum Wave-Lengths

The Situation in Regard to Rowland's Preliminary Table of Solar Spectrum Wave-Lengths

Corrections and Additions to Professor Rowland's Table of Solar Spectrum Wave-Lengths

Corrections and Additions to Professor Rowland's Table of Solar Spectrum Wave-Lengths

Preliminary Table of Solar Spectrum Wavelengths V

Preliminary Table of Solar Spectrum Wavelengths V