A major impetus behind future strong growth in the printed and flexible electronics sector will come from expansions into new markets – many of them niche segments – backed by new technologies and novel applications of existing ones.
However, an important factor will be the ability of producers to keep down their costs with high levels of manufacturing efficiency while making greater use of integrated and multifunctional systems.
This was a key message from the recent three-day conference on Innovations in Large-Area Electronics (innoLAE 2020) at Wellcome Genome Campus, Hinxton, Cambridge, England. The event, which included an Industry Day sponsored by the state-funded scale-up Centre for Process Innovation (CPI), was organized by the locally based Centre for Innovative Manufacturing in Large-Area Electronics (CIMLAE) of the UK government’s Engineering and Physical Sciences Research Council (EPSRC).
CIMLAE’s mission is to tackle the technical challenges of multifunctional integrated LAE systems, making it easier for manufacturers to supply complete system products, particularly those incorporating printed and flexible materials.
Guillaume Fichet, program manager at Cambridge-based FlexEnable, gave a presentation on his company’s development of an organic liquid crystal display (OLCD) technology, which opens up an $80 billion glass LCD displays market to ultra-thin and ultra-light, flexible alternatives.
In November 2019, FlexEnable acquired the organic thin-film transistor (OTFT) materials portfolio of Merck of Germany, opening up opportunities for making OLCDs on existing glass flat-panel display production lines. The deal enables FlexEnable to offer high-performance OTFT materials and processes needed for low -cost production of flexible organic liquid crystal displays (OLCD) in consumer electronics, automotive, retail and other markets.
Among other sectors highlighted at the conference for their high growth potential for LAE printed and flexible products was medical care. ‘’In the wearables market, one of the fastest-growing segments is electronic medical devices,’’ said Raghu Das, chief executive of the Cambridge-based electronics market consultancy IDTechEx. ‘’A lot of R&D has been done in increasing the comfort of flexible electronic products for patients.’’
Michael Kasimatis of the bioengineering department of Imperial College, London, described a hybrid solid-state composite of nanoporous silicon-copper being used to ensure that stretchable organic sensing materials adhere properly to electronic components like wiring and integrated circuits for real-world usage.
His research team at Imperial has produced proof-of-concept devices such as wearable respiration monitors for improving cardiovascular activity among the elderly.
Rusel Torah, principal research fellow at the UK’s Southampton University, reported a range of technological advances by a European Union-funded wearables research project, co-ordinated by his university. Called WEARPLEX, the three-year scheme, with 10 academic and commercial partners across Europe, aims to develop technologies for integrating printed electronics with wearable biomedical multi-pad electrodes.
The WEARPLEX approach enables individual pads to be connected in multiple configurations with the electrode’s output leads. This provides compatibility with any system for electrical stimulation and measurement of electrophysiological signals, according to Torah.
The project is working on embedded logic and current-routing circuitry based on organic electrochemical transistors (OECT). RISE Acreo, a Swedish research body and one of the WEARPLEX partners, is a global leader in the development of printed OECTs.
The transistors, which can achieve large current throughput with low voltage, is ‘’significantly less sensitive’’ to layer thickness than organic field-effect transistors (OFET), according to Torah. This makes them ‘’a viable option’’ for printing on textiles, he said.
The project, which is due to be completed in 2022, is also developing semiconductor inks for high-performance printed logic circuits, primer inks for providing smoothing layer on the fabric and conductive inks for conductive tracks between electrodes and circuit interconnects.
Under the leadership of Germany’s Technical University of Chemnitz and Finland’s Screentec, a specialist in manufacturing solutions for disposable wearable medical electrodes, the scale-up of the WEARPLEX system is planned to have a modular approach using roll-to-roll (R2R) and sheet-to-sheet (S2S) processes.
Progress in bioelectronics, the convergence of biology with electronics which is increasingly being used in medicine, has been held back by the risks and high cost of surgical implantation of bioelectronic devices to connect with the central nervous system.
Ben Woodington of Cambridge University’s engineering department gave details of flexible, shape-adaptive implants whose biocompatible materials can be used for pain management, Parkinson's disease treatments and rehabilitation. They provide user-friendly, conformable interfaces that are 100-200 times thinner than existing commercially available spinal cord stimulators.
Researchers at the university’s engineering department and at Germany’s Ludwig Maximilian University Munich have combined to raise the acceptability of neural implants by using highly-conformable and flexible organic substrates which limit neural tissue damage during implantations, according to Vincenzo Curto, a member of the joint research team.
Bioelectronics is also helping to integrate organic electronic devices with living plants to improve their functionality. Eleni Stavrinidou, assistant professor in organic electronics at Linkoeping University, Sweden, described implants of capillary-based organic electronic ion pumps (c-OEIP) for controlling the photosynthesis and transpiration rate of leaf stomata. The university’s organic electronics unit is also developing OECTs for monitoring biomolecules in plant systems to help plants adapt to environmental changes.
Food and agriculture is another potential high growth area for printed and flexible electronics.
‘’For sensors, agriculture is a huge market,’’ said Gregory Whiting, an associate professor at Colorado Boulder University’s mechanical engineering department. He told the meeting about new sensors for in-situ monitoring at a high-spatial density of moisture and ion concentrations in soils to enable precise applications of fertilizers and water. Biodegradable sensors with printed conductors based on composites of biopolymers and soluble metals have been developed to be in direct contact with the soil and to be read remotely throughout the growing season.
Daniel Tobjoerk, senior scientist at Cambridge Display Technology (CDT), Cambridge, England, which has been developing gas sensors for regulating plant growth and for detecting rot in stored crops, claimed that the electronics market segment for curbing food waste had enormous potential in value. ‘’For post-harvesting applications, smart agriculture is a massive market,’’ he said.
Firat Gueder, senior lecturer at Imperial College’s bioengineering department, explained the advantage of cellulose as a substrate for gas sensors for detecting volatiles from the degradation of protein-rich food products. His research team had discovered that cellulose is a highly effective hygroscopic biopolymer for measuring gaseous analytes.
But being paper-based, the sensors also have, he noted, ‘’near-zero cost.’’ With these and many other new printed and flexible electronic products, low unit costs are still an essential prerequisite for success in the market.
