Washable and flexible biometrics embedded into fabric.

Window coverings that can harvest solar energy.

Mechanical parts that can collect and transmit data on their status for predictive maintenance.

These are just a few examples of the applications at or near full-scale commercialization that in some way benefit from printable, flexible and wearable electronics (PE).

What is PE?

Inks that can conduct electricity – made from materials such as graphite, silver, and copper – are printed on a substrate at high enough density to form a complete electronic circuit, but thin enough to have negligible impact on the substrate thickness. The substrate can be rigid, flexible or even stretchable, such as paper, plastic, fabric or glass.

These inks can be applied through traditional printing processes through fast and inexpensive automated processes, such as those used in the commercial printing industry for newspapers and magazines. Components can also be embedded though additive manufacturing processes, such as 3D printing or in-mold electronics. A related field involves conductive yarns which can be woven into fabric to create smart garments.

PE can be used to create discreet components such as displays, conductors, transistors, sensors, light emitting diodes, photovoltaic energy capture cells, memory, logic processing, system clocks, antennas, batteries, and low-voltage electronic interconnects. These can be integrated into simple systems that, for example, can record, store, and then transmit temperature information. Fully functional electronic systems can be created in this way, or discreet components and sub-systems can be produced to function as part of a hybrid solution with conventional silicon-based integrated circuits or components.

Advantages over conventional electronics

Compared to traditional silicon, PE components are lighter, thinner, cheaper to manufacture and capable of being flexible or even stretchable. As an additive technology, they can be produced without the capital-intensive manufacturing processes typical of silicon that are often wasteful and environmentally harmful.

With PE, electronics can be embedded into printed 3D devices and components. We can enable a new generation of wearable healthcare technologies, smart fabrics, flexible electronics, connected homes that conserve energy, and even smart packaging that can reduce food and packaging waste. 

Here are a few examples:

Organic photovoltaics (OPV)

OPV cells use conductive organic polymers or small organic molecules for light absorption and charge transport to produce electricity from sunlight by the same photovoltaic effect used by conventional solar cells. This technology is another example of the switch from silicon to carbon-based electronics, with the resulting benefits of low cost, high production volume and significant environmental benefits.

These flexible solar cells based on thin films can potentially be incorporated into a variety of materials— from window blinds to glass and roofing materials. A building’s entire exterior could be turned into a power generator, in a far more flexible and cost-effective way than is possible with conventional inorganic solar cells.

In addition to energy harvesting applications for residential and commercial buildings, OPV also has applications in automotive, point-of-sale and advertising, apparel and consumer electronics. New high sensitivity OPVs, such as those from CPEIA Member company Wibicom, can even harvest ambient light for low-power applications such as self-powered sensors and self-powered antennas.

But some technical hurdles remain to be overcome for mass adoption of OPV to be achievable within another decade. Work is ongoing around the globe to increase the efficiency, stability and strength of organic cells. The industry’s goal is to develop OPV cells suitable for mass production that can deliver a power conversion efficiency (PCE) of least 10 percent for 10 years.

Smart parts

PE is ideal for additive manufacturing processes like 3D printing and in-mold electronics, to embed functionality inside a part or assembly. This reduces the bulk and expense of external hard wiring to connect electronic systems and assemblies.

By the same token, intelligence can be added to a part with low-cost printed electronic tags, labels and serialized sensor matrices. These are digital fingerprints that can be used to identify and authenticate a part.

With PE tags and sensors, parts and assemblies can collect and transmit data on their use and usage conditions, heat, stress and so forth. All this data can be collected and stored in the cloud, for remote monitoring and predictive analytics to carry out preventative maintenance and repair. This intelligence can be economically added to anything from a wind turbine blade, to a building systems such as elevators and HVAC, or any of the subsystems or structural members found on automobiles, aircraft and so forth.

Anyone who uses a blood glucose monitor is already using a printed sensor – it’s on the disposable test strip. This kind of sensing technology has been on the market for some time. The next step is to develop the conductive ink and paste, substrate and enclosure materials needed for more rugged and long-term applications. Efforts are already well underway. Market research firm IDTechEx predicts the overall market for printed sensors will reach US$7.6 billion by 2027.

Wearables, including smart garments for health and wellness

Wearable technology has gone mainstream in a few short years. Many of us are taking advantage of devices worn on our person to enhance our athletic performance, monitor health and fitness indicators such as heart rate and breathing, and ensure the wellbeing and safety of the elderly. Wearable devices already on the market include bracelets, watches and necklaces, as well as athletic wear such as sports bras and shirts. We even have smart temperature stickers that monitor a child’s vital signs during sleep.

The discrete form factors, flexibility and cost advantages of PE versus conventional electronics are crucial to make most of these devices and applications affordable and practical. Another rapidly growing application area is smart garments and textiles.

Take, for example, OMSignal. This Canadian company develops functional smart apparel to help people live active, fit and healthy lives. It is, for example, the smart textile and software technology behind Ralph Lauren’s PoloTech collection.

Last year, OMSignal launched the OMBra. From a biomechanical standpoint, this smart garment is designed to absorb the strain and pressure of running. But it is also a piece of fitness technology, equipped with three heart rate sensors, a breathing wire (the first on the market) and an accurate motion/accelerometer sensor. 

Patent-pending algorithms in the OMbra app combine heart rate and breathing to provide personalized feedback. The more a woman runs, the more the app adapts to her body so she can meet her weight goals and safely improve her training.

Where is the PE market going?

Global revenues for products using PE in 2016 is estimated at US$26.9 billion, an annual increase of 31.8 per cent since 2010. Consulting firm Smithers Apex expects the market to grow to an estimated US$43 billion by 2020. 

A separate forecast from IDTechEx predicts a US$70-billion market by 2024, for applications ranging from organic LEDs (OLEDs) to conductive inks for a variety of applications. 

Hundreds of millions of dollars in joint funding initiatives between U.S. industry, academia and government have been announced in the past few years to create the Flexible Hybrid Electronics Manufacturing Institute, The Revolutionary Fibers and Textiles Manufacturing Innovation Institute, and the Smart Manufacturing Innovation Institute.

As the united voice of Canada’s PE sector, the Canadian Printable Electronics Industry Association (CPEIA) is working to secure similar multi-stakeholder support for comparable industry-driven development and commercialization initiatives here in Canada.