Anti-Reflective Hybrid Coatingsfor Glass ApplicationN. Arfsten, P. Buskens, R. Habets, T. Kockelkoren, H. Langermans,A. Overbeek, R. Rijk, M. Rooijmans, J. Scheerder,Kornelia Matloka
GPD Finland 2011
Outline
• DSM and DSM EBA Advanced Surfaces
• Introduction to anti-reflective (AR) coatings
• DSM AR coating technology and applications
• DSM ‘s AR coating performance for solar cell cover glass
• AR coating application technologies
Glass Performance Days, Finland 2011
DSM -100 Years Of SuccessfulTransformations
Life Science Products
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Performance Materials
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Chemical engineering
Polymer technology
Fine chemicals
Material science
Mechanical engineering
Biotechnology
Technological competences1902 1930 19701950 1990 2000 2010
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Evolution
Royal DSM N.V. uses its competences in life sciences and materials sciencesto create solutions that nourish, protect and improve performance
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Nanostructured Functional Coatings
Functional coating:A functional coating is a coating which achieves any additional function beyond that of theusual protective and decorative.
Nanostructured hybridshybrid materials prepared through hydrolysis and condensation of metal oxide precursorsin the presence of organic molecules, polymers or biocomponents;controlled/structured on nano-level
DSM examples:Anti-reflective on glass and plasticsAnti-staticAnti-foulingAnti-foggingSelf-cleaningAnti-microbial (BMM)Lubricious (BMM)
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Product Portfolio & Pipeline
Available antireflective products:
claryl: picture framing/art displaysKhepriCoatTM: outdoor durable coating for lighting cover glass
Future product pipeline (combination of functionalities):
For electronic display and thin film solar markets:• Easy-to-clean + antireflective coating• Anti reflective coatings (one side) and conductive coatings (other side) for glass
and plastic substrates• Functional materials
Glass Performance Days, Finland 2011
Antireflective Coatings
Reflection can be reduced and transmission can be increased by usingantireflective coatings.
In general there are 2 different anti-reflective coating technologies:
1.Interference-type multilayer systems– Expensive
2.Single layer nanoporous silica-based systems– Refractive index and thickness tuned to minimize the total reflection
Glass Performance Days, Finland 2011
Single Layer Antireflective Coatings:“Moulton Relationship”
Mec
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Optics
Moulton US2432484 (1943)Moulton US2432484 (1943)
DSM’s coating(Picture courtesy of Corning)
Glass Performance Days, Finland 2011
Single Layer Antireflective Coatings:Traditional vs.Core-shell AR Coatings
Binder
Solid silica particles
~100nm
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Coating’s Surface Analysis
White Light Optical Profiler
AFM image
There is a certain surface roughness, but noton such scale as in the traditional AR
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Silica precursor
alcohol
Preparation Core-Shell Particles
aqueous polymerdispersion
Coating application methoddepends on the product application
Glass Performance Days, Finland 2011
DSM’s Antireflective Coating Technology
• DSM’s AR coating can be applied by various coating technologies:– 2-sided: dip coating– 1-sided: roll, spray or slot-die coating
• DSM’s AR coating can be applied on different types of glass:– Float glass– Patterned glass– Borosilicate glass
• Flexible curing conditions:– Batch ovens (450 C)– Temper ovens (700 C)
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Applications
Value proposition:improved light transmissionfor higher yield/ energy saving
•Photovoltaic cells
•Solar thermal collectors
•Horticulture
•Lighting
•Lenses
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Value proposition:improved light transmissionfor better visibility
•Picture framing
•Refrigerator and freezer doors
•Cabinets, shop furniture
•Architectural glass
•Decorative glass
•Displays
1-sided coated 4 mm ultrawhite float glass• KhepriCoat™ has an excellent performance on float and on rolled glass• Maximum gain/peak in transmission (perpendicular) up to 4%• Average gain in transmission up to 3% (depending on wavelength range)
Transmission Single side Khepricoat(TM) on 4mm Pilkington Optiwhite
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% gain
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Transmission single side Khepricoat(TM) on 4mm SG Albarino-T
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Optical Performance on 4.0 mm Float Glass
Glass Performance Days, Finland 2011
By varying coating thickness optical properties can be tuned
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wavelength [nm]
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Dipping speed(mm/sec):
Tunable optical performance
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Optical Performance:Angle-Dependent Transmission
• The gain in transmission increases at higher angles of incidence to almost10% (green line)
• The biggest gain in transmission is obtained at angles above 30 degrees
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uncoated glassAR-coated glass
Transmission gain
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• Passed all tests according to IEC 61215 (damp-heat, humidity-freeze,thermal cycling)
• TüV certification for commercial modules withKhepriCoat™ AR coating obtained
• No degradation during damp-heat test for 2000 hours(twice the IEC test norm)
• Up to 3% performance increase at normal angle
• Up to 5% performance increase at 60 deg
Performance of KhepriCoat™ coatedPV-modules
Module tests performed at Photovoltaik Institut Berlin (www.pi-berlin.com)
Application Process Development
Two sided coatings:
• A commercial dip coating plant is operational at DSM (®claryl)• DSM provides technological support to customers
Single sided coatings:
DSM is commercializing three technologies:1. Roll coating >3 m/min2. Spray coating – 20123. Slot die coating – pilot coating line at DSM
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DSM’s Slot-Die Process• Slot-die is known e.g. from the photographic industry to coat plastic foils with
micron thick, non-optical coatings
• DSM adapted the technology to make it suitable for high speed deposition ofoptical coatings on rigid (glass) substrates (thickness = 100 – 150 nm; thicknesstolerance = 2 nm)
• DSM patented the adapted process
• Pilot-line available at DSM
One-Side Coating Processes
Choice of process depends on desired production speed and opticalrequirements of final product
• Spray coating: high production speeds possible (up to 20 meters perminute); low to medium level of optical homogeneity
• Roll coating: medium production speeds possible (up to 5 meters perminute); medium to high level of optical homogeneity
• DSM’s slot-die process: high production speeds and high level of opticalhomogeneity
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Acknowledgements :
R&D AR development & customer support:Nanning Arfsten, Jens Thies, Pascal Buskens, Roberto Habets, PatrickVrijaldenhoven, Harm Langermans, Ad Overbeek, Jurgen Scheerder, Ron deRijk, Marnix Rooijmans, Tessa Kockelkoren
Business development:Hugo Schoot,Chantal Jorissen
DSM Contact Persons
Mr. Hugo SchootBusiness Development Manager
Dr. Kornelia MatlokaR&D Scientist
Glass Performance Days, Finland 2011