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Low-cost, Green, Large Scale Manufacturing of new age conducting nanowires displays

Final Report Summary - NANODIGREE (Low-cost, Green, Large Scale Manufacturing of new age conducting nanowires displays)

Executive Summary:
The SME partners of NanoDiGree have identified an opportunity to develop high added value transparent conducting films possessing unique properties via a low-cost, an environmentally friendly and high- tech production process. Subsequently, NanoDiGree project is orientated in the design, synthesis and large scale processing of novel conductive/transparent inks containing Cu based nanowires (NWs), which will be fabricated into anodized aluminium oxide (AAO) nanoporous template via advanced pulse electrodeposition (PED) method. Finally the roll-to-roll ink-jet printing technique will provide an absolutely scalable process to deposit Cu based nanowire inks onto flexible PET substrates and form a thin transparent conductive layer for displays and touch screens.

Project Context and Objectives:
NanoDiGree aims to replace Indium-Tin Oxide (ITO) layers in LCD displays and OLEDs by producing new age flexible displays. In most display industries manufacturing is based on ITO Transparent Conducting Films (TCF). However, these materials present several disadvantages: high cost, limited supply, fragility and lack of flexibility while, there is also a high cost for the layer deposition (vacuum deposition technique) required for the manufacturing of the final devices. Metal-nanowires (NW) fabricated via chemical solution methods have already been proven as suitable for their effective integration in transparent conducting touch screen to act as electrodes, This project takes advantage of Cu abundance and low cost (in relation to indium and silver NWs) to realize this potential in combination with the application of electrodeposition technique which is green, low cost and provides excellent opportunities in controlling the NWs characteristics compared to the solution process.

The deposition of Cu based NWs is conducted in the pores of the AAO nanoporous templates. By optimization of the Pulse Electro-Deposition process, uniform NWs are intended to be produced, providing controlled mechanical / electrical properties and characteristics (diameter and length). An important task is the optimisation of the dispersion of the NWs in the polymeric ink in order to prevent agglomeration as well as, to optimise NWs concentration in order to exceed the percolation threshold. The solution will be water based, and the addition of appropriate solvents will offer the optimised viscosity of the ink. The next step involves the deposition of Cu based NWs inks onto the flexible PET substrate that will be realised by a Roll-to-Roll printing technique ensuring the uniform dispersion of NWs onto the substrate. The inkjet printing technique is one of the most scalable methods, suitable for the deposition of thin films. The consortium has to overcome limitations of the current inkjet printing method for the deposition of metal NWs. Finally, the substrate and the film will be heated and/or pressed at low temperature to form a transparent conductive layer with strong adhesion on the substrate.

Project Results:
Main technical results are:
-Method of producing high quality Cu-NW and CuNi-NW pulse electrodeposition (PED) method
-Method and ink formulation to prevent oxidation of Cu-NW and CuNi-NW
- Precision spray printing for high quality printing and minimisation of film thickness fluctuation across the film area while obtaining the desired film thickness.
-Touch screen demonstrator to prove Nanodigree proof of concept.

Potential 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 developments, 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.

List of Websites:
The project website is accessible on the public domain at the URL address: