Optical properties of porous Si/PECVD SiNx:H reflector on single crystalline Si for solar cells (original) (raw)
Related papers
Solar Energy Materials and Solar Cells, 2006
Thin films of silicon oxide and silicon titanium mixed oxides are deposited on solar collector glazing in a sol-gel dip-coating process based on alcoxide precursors. Spectrophotometry is used to characterize the relation of film thickness and withdrawal speed for the precursor solutions, and to determine the refractive index of individual layers of the mixed oxides. The inferred dispersion relations nðlÞ are compared to the predictions of effective medium theories. Based on the knowledge of the optical properties of individual layers, multilayer interference stacks are designed. Multilayered samples of superior quality are deposited by sol-gel dip-coating in a particle-free environment. The final optical performance of the multilayer stacks are characterized in terms of the visible reflectance R VIS , CIE color coordinates, and the solar transmission T sol . Values of up to 2.4 have been attained for the energy efficiency of the colored reflection M ¼ R VIS =ð100% À T sol Þ. The produced coatings combine a bright colored reflection with an acceptable solar transmittance, and are thus well suited for the application in colored glazed thermal solar collectors. This novel type of colored glazing opens up new perspectives for the architectural integration of thermal solar collectors, e.g. as solar active glass facades. r 2006 Published by Elsevier B.V.
Novel GIMS technique for deposition of colored Ti/TiO₂ coatings on industrial scale
Materials Science-Poland, 2016
The aim of the present paper has been to verify the effectiveness and usefulness of a novel deposition process named GIMS (Gas Injection Magnetron Sputtering) used for the flrst time for deposition of Ti/TiO₂ coatings on large area glass Substrates covered in the condition of industrial scale production. The Ti/TiO₂ coatings were deposited in an industrial System utilizing a set of linear magnetrons with the length of 2400 mm each for covering the 2000 × 3000 mm glasses. Taking into account the speciflc course of the GIMS (multipoint gas injection along the magnetron length) and the scale of the industrial facility, the optical coating uniformity was the most important goal to check. The experiments on Ti/TiO₂ coatings deposited by the use of GIMS were conducted on Substrates in the form of glass plates located at the key points along the magnetrons and intentionally non-heated during any stage of the process. Measurements of the coatings properties showed that the thickness and opt...
Multilayered Al2O3/SiO2 and TiO2/SiO2 coatings for glazed colored solar thermal collectors
Solar Energy Materials and Solar Cells, 2005
Our aim is to study the possibility of integrating dielectric multilayer films deposited on glass substrates as a colored glazed cover for thermal solar collectors and building faces. The cover glass should ideally reflect only a narrow band of visible light while transmitting the rest of the sunlight spectrum to minimize energy loss. A compromise between the visible reflectance and the solar transmission has to be found. In our multilayer interference filters, we used two materials having, respectively, a high and a low refractive index. We studied two cases: Al 2 O 3 / SiO 2 and TiO 2 /SiO 2 . The thin films were deposited by reactive magnetron sputtering. In situ XPS characterizations were carried out for each film by transferring the sample from the deposition chamber to an ultra-high vacuum analysis chamber without breaking the vacuum. The growth rate of TiO 2 , SiO 2 and Al 2 O 3 single layers on Si substrates were monitored by in situ laser reflectometry. Spectroscopic ellipsometry was used to determine the optical constants and the thicknesses of every individual dielectric layer. Reflectivity measurements of the experimentally realized dielectric multilayers deposited on glass substrates confirmed their transparency and their good accordance with the simulation. The multilayers were also characterized by their solar transmission, visible reflectance and a factor of merit. r
Multilayer Antireflection Coatings for Cover Glass on Silicon Solar Modules
IEEE Journal of Photovoltaics
The cover glass on solar modules provides protection for the underlying solar cells but also leads to two forms of power loss: reflection losses and soiling losses. In this work we report on the design of a broadband multilayer anti-reflection (MAR) coating designed for use with silicon modules and its advantages over commercial porous SiO2 sol-gel coatings. The six-layer anti-reflection coating comprising SiO2 and ZrO2 has then been deposited on glass using high-rate pulsed DC magnetron sputtering. The reflection losses are reduced by 2.4% absolute compared to uncoated glass, whereas commercial SiO2 coatings reduce reflection by 2.2%. The increased light reaching the solar cell improves the short-circuit current density (Jsc) and spectral response, increasing the conversion efficiency from 17.1% to 17.5%, a relative increase of 2.34%. The coating is environmentally robust and abrasion resistant, whereas porous SiO2 AR coatings are susceptible to abrasion damage and water ingress. The sputtering process used to fabricate the MAR coating is used for high throughput applications by most major glass manufacturers. We also explore the addition of a thin hydrophobic layer of refractive index n=1.35 to the outer surface of the MAR coating. Addition of the hydrophobic layer increases the water contact angle of the MAR coating from 7 • to 114 • , with a significant increase in anti-soiling properties without compromising AR performance. MAR coatings offer improved light transmission and improved durability over commercial porous SiO2 sol-gel AR coatings.
Hwang/Characterization, 2012
Thin film multilayer anti-reflection coatings (SÍO2/SÍ/S1O2) having thicknesses 286/571/143nm were deposited by RF magnetron sputtering deposition technique on 0.5mm thick Si(100)-substrates. Post-deposition annealing is also carried out in the temperature range 150-650°C for 4hr at the rate of 10°C /min. Si Optical window was designed at 4.2μπι wavelengths and correlated with modeling software. The films are transparent in the 3-5um band of the electromagnetic spectrum, firmly adhered to the substrate. The prepared multilayer thin films are characterized optically and structurally using a spectrophotometer, an atomic force microscope, x-ray diffraction and a scanning electron microscope. Optical and structural characterizations show that the %transmittance is between 60% and 75%, no appreciable change in crystal structure and roughness of coatings vary between 9 and 25 nm when annealed in the temperature range of 150-650°C. Local elemental characterization on the surface of the thin film was carried out using energy dispersive spectroscopy. The quantitative result of energy dispersive spectroscopy has also shown that the ratio of Si to O on the film is 0.67:1.
Glass and Coatings on Glass for Solar Applications
Springer Handbook of Glass, 2019
In this chapter we discuss the crucial role that glass plays in the ever-expanding area of solar power generation, along with the evolution and various uses of glass and coated glass for solar applications. We begin with a discussion of glass requirements, specifically composition, that enable increased solar energy transmission, which is critical for solar applications. Next we discuss anti-reflective surface treatments of glass for further enhancement of solar energy transmission, primarily for crystalline silicon photovoltaics. We then turn to glass and coated glass applications for thin-film photovoltaics, specifically transparent conductive coatings and the advantages of highly resistive transparent layers. Finally, we discuss the use of coated glasses as mirrors for concentrated solar power applications. We also discuss various fundamental and manufacturing challenges for glass and coatings on glass in solar applications.
Renewable Energy and Power Quality Journal, 2010
In this work, titanium dioxide (TiO 2) thin films have been deposited on glass and monocrystalline silicon by Atmospheric Pressure Chemical Vapor Deposition (APCVD) technique using titanium tetrachloride TiCl 4 as precursor. The structural, electrical and optical properties of the prepared TiO 2 thin films were evaluated by Atomic Force Microscopy (AFM), Four Point Probe (FPP) and Spectroscopic Ellipsometry (SE), respectively. These properties were exploited for application of the TiO 2 layers as antireflection coatings on monocrystalline silicon solar cells. Our experimental results show that the deposited TiO 2 thin films were polycrystalline, homogenous, compact and relatively smooth. The measured average optical transmittance of the TiO 2 films was about 85-90%. From the ellipsometry analysis, the refractive index of our TiO 2 thin films was found to be n=2,25 at the wavelength λ= 550 nm, with a thickness of 56,2 nm. These experimental results obtained by APCVD are in excellent agreement with the computed results of the TiO 2 refractive index and thickness required for a high quality antireflection coating in industrial conditions. The obtained results demonstrate the real opportunity of the APCVD technique to prepare high quality antireflection coatings for crystalline solar cells. This indicates that the APCVD antireflection coatings may have a high potential industrial application.
Functionalization of Surfaces with Optical Coatings Produced by PVD Magnetron Sputtering
Research Perspectives on Functional Micro- and Nanoscale Coatings
This chapter describes the functionalization of the surface of the glass through thin film inorganic coatings. Such filters called dichroic filters, following the physical principle of interference of light using the rules of optical physics. The design of the optical multilayer materials with high and low refractive index and optimizing the predetermined optical responses. The AFM quantify the real thickness and, calibrate the deposition plant, using as an input data for the simulation to evaluate the dispersion index refraction and absorption. The dichroic filters separate the incident radiation into two or more predetermined optical bands. The materials used are deposited using PVD Reactive Magnetron Sputtering, allows to increase the deposition rate, to obtain good homogeneity range of the surface deposited. The set point of deposition which allows to obtain stoichiometric oxides is analyzed with the technique RBS. These optical filters, also called dichroic are applied in the r...
Development of High Performance Industrial TCO Glass for Very Large Area a-Si:H PV Modules
2011
The European project HELATHIS, executed by the five project partners signing this article, is dedicated to the improvement of the efficiency of very large area (5.7m 2 ) silicon thin film photovoltaic (PV) modules. Optical confinement has been identified by the project partners as a major source for efficiency improvement of thin film silicon PV modules. One reason of the performance gap between highly efficient laboratory solar cells and industrial modules is the poorer electrical and optical performance of the industrial TCO-covered front glass substrate (TCO glass) which is investigated in this work. The glass substrate in industrial PV modules is about 3 times thicker than in laboratory solar cells where frequently Asahi U-type TCO glass (about 1 mm thick) is used. Therefore, the glass quality has an important impact on the transmission of industrial TCO glass. Reducing the iron-content in the float glass substrate increases the integrated transmission in the wavelength range from 400-800nm by nearly 2%. The electrical properties, namely the electrical carrier mobility, of the industrial TCO layer of AGC has been increased by about 15% by improving the industrial deposition process, resulting in a thinner TCO layer with higher transmission by maintaining the sheet resistance of about 9-10 /sq. Combining both developments the integrated transmission of industrial TCO glass has been increased by more than 2%. The TCO layer properties of Asahi U-type and standard industrial TCO glass (AGC AN10) have been investigated by SEM, AFM, XRD and ARS, showing that the Asahi U TCO scatters red light more effectively into larger angles.