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The NanoDiGree is a European Union funded project under the FP7 Framework Programmes for Research and Technological Development. The aim of NanoDigree is to provide a "green" and economical viable solution for the manufacturing of displays on Smart devices such as phones, flexible displays, tablets, e-books and others. At the moment, the dominant material in this industry is based on Indium which is a raw material with increasingly limited worldwide resources whose demand is rising rapidly day by day. NanoDiGree is orientated towards the design, synthesis and processing of novel Copper based Nanowires in terms of constructing alternative Transparent conducting films, taking into account the inferior electronic and optical properties of Copper and its Alloys. The Copper-Nanowires will be electro deposited into Aluminium oxide (AAO) nanoporous-templates by utilizing pulse current electrodeposition. The produced nanowires will be dispersed in “green” solvent mixture in order to develop the printing inks for the afterwards production of the films. Finally, Roll-to-Roll printing will be used in order to apply thin flexible conductive-transparent films on suitable polymer substrates that will be used as the flexible devices. The purpose of these films is to compete against and ultimately replace Indium Tin Oxide (ITO).

The goal of the NanoDiGree proposal is to intercept the trend of integration of all supply chain manufacturer of displays in Asia by producing high added value components in Europe. The impact is expected to be significant, considering that the alternative transparent conducting films (TCFs) address the need of constantly growing market sectors, which nowadays widely use (ITO). These are the electronic displays as well as the solar panels manufacturers. Applications include: touchscreens, Liquid-crystal display televisions or Organic Light Emitting Displays (OLEDs), solar cells top electrode layer, energy conserving architectural windows “smart windows”, defogging aircraft cockpit windows and luxury car windows.

Issues addressed by the project
Transparent conducting films, which are optically transparent and electrically conductive, are widely used in touchscreens and flat panel displays for consumer electronics devices. Such films would have even greater opportunities if they provided key benefits compared to indium tin oxide (ITO), which at present is the key type of transparent conducting oxides (TCO) applied in the aforementioned applications. The limitations of ITO include:

1.	brittleness, which can make ITO unsuitable for flexible substrates/displays

2.	potential shortages of indium

3.	high cost of ITO

4.	processes employed that are not environmentally friendly (i.e. high-temperature deposition methods)

Thus, overall ITO can restrict the selection of the substrate. There has been keen interest and activity in developing transparent conductors using alternative materials to ITO.

Cu-based nanowire networks demonstrate significant potential to serve as alternative conducting media in transparent conducting electrodes The NanoDiGree project exploits the abundance and low cost of Cu (in relation to indium) in order to realize this potential. Although metal-nanowires have already been proven suitable for their effective integration in transparent conducting touch screens to act as electrodes via solution methods, Cu nanowire network thin films have not yet reached the excellent performance of ITO films. The proposed solution includes a variety of advantages such as lower cost, flexibility as well as substantially higher efficiency of the transparent conducting films, while ensuring manufacture in an environmentally friendly way. This is being achieved by the development of low-cost and environmental friendly sequences of production methods.

Indium is a raw material whose demand is rising rapidly day by day. According to statistics the worldwide reserve base of indium is estimated to be approximately 6,000 tonnes on earth, based on current consumption rates only 13 years supply of indium is left. Indium is a highly expensive material, and because of its limited natural resources its price has shown an upwards trend over the resent years. It was observed that from 2006 to 2009 indium price ranged from 290 Euros/kg to 700 Euros/kg. This means that an increase of over 170 Euros/kg per year is being observed 130 Euros/kg per year (20% growth rate estimated through 2013). An immense amount of scientists are intensively working on the perspective to overturn this situation taking into account the fact that ITO suffers from several drawbacks. ITO films have a limited flexibility which means that the more bending cycles the more cracks are being created in the film and as a result the produced films gradually lose their conductivity- leading to a decrease of the electrical performance.

Scientific and technical advancements
The overall concept of the NanoDiGree project involves the production of the appropriate metal nanowires, taking into account the inferior properties of Cu. The deposition of Cu nanowires is being conducted in the high ordered pores of the anodized aluminum oxide (AAO) nanoporous templates. The AAO have been selected to act as ideal templates, featuring desirable characteristics, such as tunable pore dimensions, good mechanical strength and thermal stability.

The desired AAO nanoporous templates will be produced by the anodisation process of Al sheets under a constant voltage in the desired acid electrolyte and electrolyte concentration in order to achieve and control the appropriate pore diameter. Subsequently, the electrodeposition of Cu-based metal ions into the pores of the high ordered hexagonal AAO nanoporous template will be achieved. The main purpose is to obtain optimised pores in order to produce uniform nanowires providing the desired properties as well as characteristics regarding the diameter and the length of the nanowires. This is achieved by optimization of the pulse electro deposition (PED) procedure. The next step involves the formulation of the Cu-based nanowire inks that is achieved by the dispersion of the nanowires into the appropriate solutions. The solutions are water based, and through appropriate solvents the desired viscosity is achieved. An important task is the optimization of the dispersion in order to prevent agglomeration as well as to ascertain that the nanowires exceed the percolation threshold. The next step involves the deposition of Cu nanowire inks onto the flexible PET substrate.

For the deposition, a Roll-to-Roll inkjet printing technique is employed,ensuring the uniform dispersion of nanowires onto the substrate. The inkjet printing technique is one of the most scalable methods, suitable for the deposition of thin films. The roll-to-roll inkjet printing technique will provide a low-cost, low energy and absolutely scalable technique to deposit Cu-based nanowire inks onto flexible PET substrates and form a thin transparent conductive layer. Finally, the substrate and the film will be heated and pressed at low temperature (below 75oC) to form a transparent conductive layer with strong adhesion on the substrate.

Consortium Participants
The consortium has 6 participants from 5 different member states; Greece, Austria, United Kingdom, Spain & Cyprus.

•	The National Technical University of Athens (NTUA) is the educational institution of Greece in the field of technology. The General Chemistry Laboratory within the School of Chemical Engineering at NTUA has been involved in the synthesis and characterisation of various metal based materials and coatingsproduced by electrodeposition in the nano and micro scales.

•	Happy Plating is an Austrian company acting as a bridge between applied research and industrial production. Happy Plating develops trend-setting technologies in the fields of Pulse Plating and advanced surface finishing, dispersion coatings and functional composite coatings via (nano-) particle codeposition.

•	Printed Electronics LTD (PEL) has state of the art inkjet printing, screen printing, valve-jet systems for high viscosity fluids, ink characterisation, ink droplet visualisation and surface energy modification equipment. PEL has led and been members of a number of TSB and FP7 projects and run very popular training courses for inkjet printed circuits and electronics.

•	B-DIVISION is a specialised multi – spoke industrial company established over 40 years ago with a special emphasis on general and specialised products, coating processes and fabrication business. B-DIVISION has adopted a policy of continuous investment in R&D equipment and technology

•	Inspiralia is a non profit Research & Technology Development Group encompassing six individual institutes. Inspiralia has been growing its activities in the direction of materials science; moreover they are active in a broad spectrum of application areas; such as renewable energies, construction materials, multi-coatings, nano-materials, protection, etc.

•	CETRI provides focused research on Engineering and Information Technology. CETRI is located in Cyprus, producing cost effective solutions for entrepreneurs, independent enterprises and academic institutions.

•	CERTH / I.RE.TE.TH is a legal, non-profit entity organized under the auspices of the General Secretariat for Research and Technology (GSRT), of the Greek Ministry of Development. I.RE.TE.TH 's mission is to conduct basic, applied, and technological research that leads to new materials, products and services with industrial, economic and social impact.

Expected results and impact
The goal of the NanoDiGree project is to intercept the trend of integration of all supply chain manufacturers of displays in Asia by producing high added value components in Europe. The proposed technology will achieve lower production cost, high performance and will increase the possibilities of new disruptive technology in display technology (flexibility, mechanical stability). Furthermore, NanoDiGree will reduce the environmental impact and will offer EU independence from 3rd countries in the supply of basic materials for the electronics/Display Industry.

The project will provide growth opportunities for the participating SMEs through research and help them to carry out or outsource research results, acquire technical know-how and train their employees to incorporate new evelopments, while contributing to EU strategy for economic growth. In the consortium there are participants (SMEs) with little or no research capabilities, which will provide input to the RTDs regarding their technological problems. Therefore, through NanoDiGree new improved products will increase the SMEs‟ market potential and strengthen their competitiveness. The project conforms to the EU‟s Policy of increasing the Competitiveness of SME‟s at the European and Worldwide level.

Pricing

ITO Coatings have retail prices higher than 22.5€/m2. The cheapest viable alternative to ITO is metal nano-particle transparent conductors with a price of 7.5€ /m2, but with serious disadvantages compared to NanoDiGree‟s alternative. The main competitors are metal nanowire-based conductors with prices ranging from 23 to 52€/m2. The NanoDiGree will have an initial cost of 20€/m2, so it will be cheaper than the other products with similar characteristics and will also have better characteristics such us longer product life. The Consortium assumes that through mass production and further improvements in the production process, the average cost will further fall by 20%. The initial selling price is €24 and there will be the potential to lower the price if there is more competition in the future. So the consortium considers that the product will be very strongly competitive.

Time to market

NanoDiGree has arguably high research content and high development content. The SMEs are aware of this, but appreciate that it is necessary in order to develop the product. An advanced prototype near to market will be developed near the project end. Full commercialization will require further field-testing to satisfy cost, performance, quality and safety criteria in full-scale production and will take place during the last months of the project. All the proper regulations such as standard testing will be performed during the project. After project completion there will be more effort spent for further improvements of the existing NanoDiGree product until it will be ready to be mass produced and sold, which will take about 12 months more.

Work Package Overview
The NanoDiGree project is split into 8 Work Packages covering all aspects of the work being conducted.

WP1: Generation of specifications and requirements. In this WP the partners generate data on the overall specifications and requirements of materials, chemistries and equipment for all the steps involved in the project.

WP2: Production of AAO high ordered nanoporous template. During this WP an appropriate large scale method is being developed to achieve highly ordered AAO templates. The optimum electrochemical parameters for the production of AAO nanoporous templates will be determined and the produced templates will also be characterized.

WP3: Production of Cu-based nanowires via electrodeposition. During this WP the pulse electrodeposition will be set up, the optimum electroplating conditions will be defined and the production of Cu nanowires will be conducted.

WP4: Cu-basednanowire inks production. The dispersion of Cu nanowires in aqueous environmentally friendly inks will be achieved in this WP.

WP5: Roll-to-Roll printing of Cu-based nanowires on flexible substrate. The produced Cu nanowire inks will be printed by means of R2R inkjet on PET substrates.

WP6: Proof of NanoDiGree concept. Prototypes will be assembled using the NanoDiGree TCFs, including a 4-wire resistive touchscreen, an LCD display and a flexible device display.

WP7: Dissemination and exploitation.. Dissemination of knowledge generated and technology achieved.

WP8: Project management, management of WPs and Tasks. Administrative, technical and financial project management.

References