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CORDIS - EU research results



Reporting period: 2021-10-01 to 2023-06-30

MADRAS aims to demonstrate a materials-driven improvement of OLAE devices, by establishing a fabrication methodology to assure their processability, stability and operational lifetime and their seamless integration into flexible and wearable products in a scalable competitive manufacturing process, which is In Mould Electronics (IME).
Three demonstrators: a photodetector for persons' authentication, a geo-tracking flexible tag for Industry 4.0 sector, and a OPV module, have been developed, validating the MADRAS strategy within a complete supply chain.
MADRAS has implemented a radically new manufacturing methodology for high volume production of durable OLAE based devices, while addressing the use of conventional and established industrial manufacturing techniques and adapted processing tools to deliver this innovative technology closer to market. The project goal has been to enable the future market deployment of flexible and wearable OLAE-based products guaranteeing the use of industrially and environmentally sustainable materials and processes that are attractive to the market for their advanced functionalities, robustness, durability and safety. The approach was based on a set of new materials including paper-based substrates and conductive materials to be used as inks, specifically developed for flexible OLAE products with improved properties electrical (conductivity, charge mobility) and optical (transparency) compared to common OLAE materials such as the expensive and scarce Indium Tin Oxide (ITO) since Indium is a critical raw material.
MADRAS was initially planned over a period of 36 months divided into four project phases, and later extended 3 months:
1) Materials improvement
2) Design and printing of materials and control circuits
3) Demo product manufacturing and validation
4) Demonstration of materials, processing, and demonstrators in relevant environments
The achievements have been:
- For the materials improvement: relevant target values have been achieved in the performance of materials in terms of transparency, conductivity and resistance to moisture and ambient oxygen.
- For the manufacturing process: MADRAS has developed inks and substrates specially designed for final IME demonstrators. Materials achievements were focused on the improvement of Ag NW, Ag NP, WO3 NP and PEDOT:PSS-based inks and nanocellulose-based substrates. The printing processes for selected inks have been set up, by techniques such as blade coating, slot die and screen printing. Quality checks have been done and photoactive materials have been selected to ensure high performance of the photodetector device when applying MADRAS inks. The functionality of the inks on OPD has been validated.
- Environmental impact assessment has been conducted.
- To increase the chances for the results of the project to become tangible benefits, the Key Exploitable Results (KER) have been assessed and potential new results have been identified in order to conduct efficient planning and management of each project outcome.
The project has successfully integrated a set of new advanced inks and substrates into a high-speed manufacturing methodology which is in-mould electronics (IME) to build innovative electronic devices:
a battery-free localisation tag, a fingerprint and an in-mould solar module. IME combines the functional printing of electronics and the hybridisation of electronic components with traditional plastic transformation processes, such as thermoforming and injection moulding.
The materials developed consist of a sustainable nanocellulose substrate and different types of advanced inks, including semiconducting transparent inks based on organic components, transparent conductive silver nanowires-based inks and semiconductive inks based on metal oxide nanoparticles.
The impact generated by MADRAS has increased the industrial competitiveness of European consumer electronics companies by providing them with a manufacturing approach for mass production of printed electronic products embedded in plastic parts and improved materials for soft fabrication of OLAE devices with enhanced lifetime and processability.
MADRAS main advances beyond the state of the art have been:
❖ Nanocellulose-based substrate and advanced conductive and semiconductive inks
The development of nanocellulose foils with transparency of 90% has been successfully achieved, PU-coated nanocellulose foils were also developed as sustainable substrates compatible with injection moulding processes with enhanced adhesion to thermoplastics and improved resistance to moisture. GNK developed highly transparent and conductive nano-inks based on silver nanowires (Ag NW) adapted for slot die printing and screen printing, resulted in 92 ± 2 % in transmittance at 550 nm (on substrate baseline) and 50 ± 10 Ω/£ as sheet resistance.
❖ A geotracking flexible tag for the geolocation of assets: in-mould battery-free geolocation tag using Ultra-Wide Band technology to accurately locate assets without the need for batteries, thanks to a far-field wireless power transmission solution. Ag NPs ink printed on nanocellulose foil could be efficiently leached from manufacturing scraps and prototypes by following an oxidative treatment with a diluted solution of acetic acid and hydrogen peroxide in water. Silver (I) acetate could be isolated,and Ag NPs were synthesised from the recycled silver acetate to make new recycled conductive nano inks demonstrating the closure of the recycling loop.
❖ A fingerprint reader for the shared mobility sector with a fully printed photo-detectin g frontplane.The front-plane OPD device stack was selected containing customized materials from MADRAS.
❖ A scalable manufacturing methodology applied to in-mould OPV: Technical yields of around 90% were achieved on organic solar cell modules injected with TPU. IM of organic solar cell modules have not been reported before
and could have a very high value in the market.