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2012 11-27-masterclass-conductive-inks-nanogap
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2012 11-27-masterclass-conductive-inks-nanogap

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Maserclass Conductive inks

Maserclass Conductive inks

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  • 1. Masterclass: Future of Conductive Printing Conductive Ink Development Dr Allen Reid, Commercial Director, NANOGAP
  • 2. Conductive Ink Development• Current Status – Market Size – Types of Ink – Applications• Market Drivers and Barriers• CLIP Project – Objectives – Tasks – Achievements• State of the Art Developments – NANOGAP stable and Multimodal Ag Dispersions – Intrinsiq Nano Cu – NANOGAP Ag Nanofibers – Market Round-up• Conclusions
  • 3. Current Status – Conductive Inks* • 2012 market size: $2.86 billion, dominated by silver flake inks • 2018 forecast: $3.36 billion, of which $735 million is based on nano Ag and CuConductive Ink Type / Applications Advantage DisadvantageMaterial Printing processSilver Flake Predominantly Silicon PV, membrane Cost effective for Limited conductivity, Screen printing switches, automotive, many applications thick films, surface EMI shielding, screen roughness, difficult heaters to photocureSilver Thin films, flexibility, High cost, can haveNanoparticles high conductivity, poor adhesion Silicon PV, logic and rapid photocuring Predominantly memory, packaging,Copper Inkjet Same as Ag NP, but Can oxidise and lose PCBs, RFID, OPV, sensorsNanoparticles lower cost conductivitySilver Nanowires Screen, die-slot Tranparent Conductive Compared to Difficult to inkjet Films for touchpanels, sputtered ITO, lower print, Haze solid state lighting and cost and improved PV conductivity * Adapted from IDTECHEX report: Conductive Ink Markets, 2012
  • 4. Market Drivers• Silver flake inks for screen printing will continue to dominate with largest market share – Mature technology, competitive pricing, sufficient technical performance for most applications – However, PV is biggest market, and move towards ultra thin crystalline silicon PV may require the use of inkjet printing with nanoparticle base inks• Other emerging opportunities which require printing onto delicate or irregular shaped objects will also drive a move towards ink jet and and nanoparticle inks• The ability to print onto cheap flexible substrates (polymer film, paper) requires low temperature sintering which is also driving a move towards nanoparticle inks• For transparent conductive films (TCF) there is an overwhelming requirement for an alternative to sputtered ITO due to cost, supply and performance issues – Silver nanowire / nanofiber inks can be formulated into inks and printed to form TCFs with technically superior conductive properties to ITO films for use in touch panels, solid state lighting and PV applications
  • 5. Market Barriers• Cost – Nanoparticle silver is significantly more expensive that silver flake – However with market uptake and economies of scale nanoparticle inks will become more cost competitive – Total in-use cost needs to be considered rather than a price comparison of inks• Technical – Long term stability of nanoparticle inks is a key concern for large scale commercial uptake – High resolution printing e.g. 10 microns required for transistor applications – Value chain integration including optimization of conductive ink formulations for specific printing processes and products
  • 6. CLIP: Conductive Low Cost Ink Project Objectives• Development, formulation, and feasibility of low cost inks• Development of optimized inks for screen, flexo, rotary gravure and inkjet• Optimization of inks for large area printing with high resolution, <50 microns• Prepare demonstrators
  • 7. CLIP: Conductive Low Cost Ink Project Ink Development Tasks Materials Ink Formulation PrintingUSC and NANOGAP developed PRA developed screen and flexo KTH performed inkjet trials withand supplied multi-modal Ag NP inks based on: inks developed by Sirrisdispersions Cu flakes + Cu NP Cu flakes + Ag NP Sirris performed inkjet trialsIML supplied Cu nanoparticle with inks developed by Sirrisdispersions Sirris developed inkjet inks based on:USC developed Ag coated Cu NP Sirris performed aerosol jet Ag NP dispersions trials with Ag dispersions Multi-modal Ag NP dispersions,AVL developed and supplied supplied by USC / NANOGAP Cu NP dispersionsmicro Cu flakes Acreo performed screen andSirris developed and supplied Ag flexo trials with inks developedcoated micro Cu flakes by PRACommercially sourced materialsincluded:Ferro Ag coated Cu flake,Cabot Ag inkjet ink,DuPont Ag screen and flexo inks
  • 8. CLIP: Conductive Low Cost Ink Project Ink Development Achievements• Screen and Flexo Inks (Cu flake + Cu NP) – Good Printing properties – Sheet Resistance after flash curing = 1 Ω∕□ – Work on-going to optimise formulation to improve conductive properties – Raw material cost of inks ~230€/kg, so after adding process costs and margins selling price is estimated at <500€/kg which compares favourably to commercial ink prices• Inkjet Inks (NANOGAP / USC Uni-modal and Multi-modal Ag) 5.00 Sheet resistance (ohm per square) dropspacing 20 µm, PEL, 1 Layer – Good printing properties from all Uni-modal and multi-modal Ag inks 4.00 – Sirris demonstrated lower sintering temperatures and improved conductivity of tri- modal ink compared to equivalent multi-modal ink and commercial reference 3.00 2.00• Aerosol Jet Inks (NANOGAP / USC Uni-modal and Multi-modal Ag) 1.00 – Good printing properties from all Uni-modal and multi-modal Ag inks – On paper, bi and tri-modal inks achieved 3.5 to 4 x bulk Ag resistivity compared to 0.00 5 x for mono-modal 0 20 40 60 80 100 curing time at 120°C (first 20 mins), then 150°C (minutes) – On PET, bi-modal ink achieved 4 x bulk Ag resistivity compared to 11 x for mono- modal mono tri commercial ink• Potential cost savings in inkjet and aerosol jet printing are achievable through more efficient use of silver (level of conductivity achieved from weight of silver deposited) as a result of performance improvements
  • 9. State of the Art Developments: NANOGAP Stable Ag NP Dispersions 125 100 42,52±14,5 nm 75 50 25 0 10 20 30 40 50 60 70 80 90 100 110 Diameter (nm) 40 nm Ag Nanoparticle dispersions with excellent long term stability available for ink formulatorsNGAP FI Ag-4101Ag Content (wt %) 30 Inkjet Trials at PEL Aerosol Jet Trials at SirrisAg Mean Particle Size 40 - 60 • Printed onto paper • Printed onto paper and PET(nm)Ag Particle Size 25-75 with Xaar print head • Laser curedDistribution (nm) (95% wt) • Cured at 120oC for 2 • On Paper, 5x silver bulkViscosity (cP) 8 - 10Surface Tension 25 - 28 minutes resistivity(mN/m)Carrier Liquid Ethylene Glycol • Resistivity = 4.4x10-5 • On PET, 11x silver bulk & IPA Ω.cm resistivitySurface Functionality PVP
  • 10. State of the Art Developments: NANOGAP Multi-modal Technology• Multi-modal particle size distributions improve particle packing leading to improved sintering and conductivity• Very small size (<1nm) AQC promote low temperature sintering• Development samples currently under evaluation Development Samples DS13 Bi-modal (40nm/6nm) in EG/IPA blend with water at <3% Aerosol Jet Printing Trials at Sirris DS15 Bi-modal (40nm/6nm) in EG with water at • Printed onto Paper and PET <3% Bi-modal (40nm/6nm) in EG/IPA blend • Laser cured DS20 with BYK 430 and water at <7% • For DS13, 4x silver bulk resistivity on PET and Paper DS29 Tri-modal (40nm/6nm/<1nm) in EG/IPA • For DS29, 3.5x silver bulk resistivity on Paper blend with water at 3%
  • 11. State of the Art Developments: Intrinsiq Nano Cu• Nano Cu produced by Plasma Process• Product is surface treated with organic coating (to promote dispersion, and reduce reactivity, but maintain electrical conductivity (patented process)• Suitable for direct formulation into inkjet ink (size < 50nm) – Formulated inks available – Between 1.5 and 5 x bulk Cu conductivity – Once sintered, the tracks can maintain performance, are equivalent to PCB tracks and can be similarly treated for extended life• Suitable for formulation with micron copper into screen print ink• Potential for – Offset litho – Flexo – Gravure• Coating process available for other metals – nickel and STEM image of nano copper with organic coating which silicon inks in development encapsulates the nanoparticles
  • 12. State of the Art Developments: NANOGAP Ag Nanofibers for TCF • Ag Nanofiber dispersions available to ink formulators • Alternatives to ITO transparent conductive films are required for many opto-electronic applications including touch panels and solid state lighting • Inks based on NANOGAP silver nanofibers have been used to prepare TCF with sheet resistance <50ohms/sq and total lightTYPICAL CHARACTERISTICS transmission > 95%NanoFiber Diameter (nm) 80 – 120 5% wt dispersions available in the following liquids (95% wt/wt) NGAP NP Ag-3103-W Water NGAP NP Ag-3103-E EthanolNanoFiber Length 5 – 50(µm) (95% wt/wt) NGAP NP Ag-3103-EG Ethylene glycol NGAP NP Ag-3103-IPA Isopropyl alcoholMean NanoFiber Length (µm) 20-30 NGAP NP Ag-3103-Bt Butanol NGAP NP Ag-3103-B Benzyl alcoholSurface Functionality PVP
  • 13. State of the Art Developments: Market Round-up* (1) • Dupont MicroCircuit Materials – Inks for thinner printed lines – Eliminating precious metal and replace with low cost conductors – Improving ink functionality e.g. for heaters and sensors – Printed conductors replacing wires e.g. heaters and automotive interiors – Inks for roll to roll printing • Toyochem – Ultrafine, low temperature, low resistivity – Screen printing as alternative to photolithography and etching – UV cured inks – Alternatives to Ag • Other companies working on thin lines and features <50 microns – Pchem – Creative Materials* Principal Source : printedelectronicsnow.com
  • 14. State of the Art Developments: Market Round-up* (2) • NovaCentrix – Ag and Cu based nanoparticle inks – PulseForge Photonic curing system – Copper Oxide based inks reduce in-situ to Copper metal during PulseForge Sintering • SunChemical – Inks for thin film PV technology – Inks for OPV for BIPV market • Metalonix – “liquid metal” inks composed of metal atoms that convert to metal at low temperature following printing • Other Conductive Inks – Vorbeck Graphene inks for screen, flexo, gravure – Bayer aqueous CNT Inks for inkjet, gravure and screen – PEDOT:PSS from Agfa and Clevios* Principal Source : printedelectronicsnow.com
  • 15. Conclusions• Nano particle based inks for printed electronics has been one of the many over- hyped areas of nanotechnology, with the market growth failing to meet expectations over the last 10-20 years• However, there is now good signs on the commercial uptake of nano particle based inks• Innovation is solving technical problems and leading to improved products – Stable nano inks, – Efficient ,and high conductivity, – Low temperature sintering• Cost issues are being addressed – With commercial uptake and scale up cost will fall and competive position will rise – Cheaper Cu systems now available – Must consider whole process cost and not jut price of ink• Supply chain collaborations and strategic partnerships are key to success – Companies that make conductive particles are not necessarily the best ink formulators
  • 16. Allen Reida.reid@nanogap.es +44 7980 866 656 www.nanogap.es