Photo courtesy of Plextronics.
Conductive ink manufacturers see plenty of opportunities for printed electronics to move into mainstream commercial applications, ranging from displays and lighting to solar cells and batteries
The market for printed electronics (PE) is beginning to materialize, as products head to the market and others move further along toward commercialization. Conductive inks play a critical role in PE, and ink manufacturers are enjoying growth.
Roy Bjorlin, global commercial director for electronic materials at Sun Chemical, noted that Sun Chemical is seeing growth opportunities throughout the PE business.
“We are doing well,” Mr. Bjorlin said. “In terms of volume, PV is a major market, and we are facing the same headwinds as everyone else. As a result, we are seeing a significant pushback in output.
“Still, we are seeing a lot of opportunity in the solar market,”Mr. Bjorlin added. “We think that thin film PV technology has legs and is on the verge of breaking out. OPV in particular is showing great promise in the building integrated photovoltaic (BIPV) market.”
Scott Gordon, market segment manager, DuPont Microcircuit Materials, said that the markets and applications for printed electronics continue to expand.
“The market research companies have been promoting the size and growth rates of several new 'Killer Application' markets for PE (OLEDs, OLED lighting, thin film PV, printed RFID), but the time-to-market for the high volume production continues to lag earlier predictions. In the meantime, there are several existing markets where sub-segments are emerging that are adopting PE,” Mr. Gordon added. “For example, there are currently several applications within automotive interiors that have adopted printed conductors as a means to lower cost, reduce space, and reduce long term liability concerns.
“There are new applications for PE that are being commercialized in 2012,” Mr. Gordon added. “In many cases, the adoption of PE is taking the form of printed conductors replacing wires. This is true in several heater applications as well as the automotive interior segment. There is also an increasing level of activity at graphics printing companies, which with experience can bring the roll-to-roll assets to produce high volume electronic circuitry.”
Steve Toyama of Engineered Conductive Materials (ECM) said that ECM has seen significant growth during the recession in both new markets as well as established businesses.
“ECM is on the verge of having a record year in 2012 with new products that will hit the market in time for Christmas,” Mr. Toyama added.
“We are seeing OLED display manufacturers moving from R&D to pilot for their solution processed device technology targeting OLED TV applications, which enables lower cost manufacturing than vapor deposition being used for today’s OLED displays used mainly in mobile and tablet applications,” said Mary Boone, director of inks business, Plextronics, Inc. “OLED lighting continues to advance with more niche products available on the market, still slower moving than displays. For conductive inks, seeing ITO replacements based on oxides and metal nanowires achieving high conductivity with high-quality films for electrode applications.”
Stuart Ganslaw, vice president - business development, Creative Materials, Inc., said that the markets for conductive inks used in printed electronics have continued to expand during the past few years.
“End-use applications that are growing at a very rapid rate include thin film solar cell grid-line inks and buss bars for displays used in cell phones, e-readers and touch screens,” Mr. Ganslaw noted. “Many of our customers who are producing printed electronic products are currently in the final phase of product development. We expect this market to expand rapidly starting in 2014.”
“We see opportunities in new areas so I would say that the markets continue to expand,” said Greg Jablonski of PChem Associates, Inc. “The driver in most cases is cost. We see positive signs that there will be successful new developments in printed electronics, but as you know, the commercialization process takes time. As always, there are a number of opportunities that look very promising at the outset but fade for various reasons.”
“Since the printing method is highly cost effective relative to existing circuit pattern formation methods, such as photo lithography and etching, we believe the market for electrically conduction silver paste is set to grow,” said Syunsuke Nomura, marketing group, Printed Electronics Dept., Toyochem Co., Ltd. “However, the cost of silver, which is used as the conductive filler, is susceptible to rate fluctuations. Use of silver substitutes as a conductive material may rise.
“Moreover, at present, ITO is predominantly used to produce transparent conductive materials through the conventional photolithography process to form coating layers,” Mr. Nomura added. “The printing method is highly anticipated to reduce production costs. If the various performance properties for coated transparent conductive inks improve to a level that meets market requirements, then this market will expand rapidly.”
“We are seeing continued interest through our supply chain collaborations,” said Dr. Allen Reid, commercial director for NanoGap. “We are collaborating and seeing developments in areas such as photovoltaics, lighting, displays and security.”
Ian Clark, sales and marketing director for Intrisiq Materials, said there is increasing interest in copper inks.
“There are already many applications of silver inks of course, and additive printing processes are seen as the way to go,” said Mr. Clark. “Although there are few commercial applications for copper inks so far, it is likely that this will change in the next one to three years as the various development programs designed to integrate more cost effective copper inks into the manufacturing processes for electronic devices come to fruition. There is a lot of development activity in the area, not only from the ink suppliers like ourselves but also from the printhead makers and the manufacturers of laser and broad band flash curing equipment.”
“Our ink shipments are continuing to increase,” said Stan Farnsworth, director of marketing for NovaCentrix. “Importantly, our PulseForge tool shipments are also increasing. This tells me that organizations are committed to moving ahead with development and commercialization of printed electronics applications. We are told by our customers that the readiness of our production-capable tools was an important part of their decision to move forward with development and commercialization of their emerging products utilizing conductive inks.
“We see that component developers are increasingly offering interesting component-level products, and as an industry we are working to cultivate confidence in end-users that this technology set can add value and is ready to go,” Mr. Farnsworth said.
Printed electronics could potentially be used in a tremendous range of products. For example, Mr. Gordon noted that displays, PV, smart cards, medical devices are good opportunities for PE, while Ms. Boone pointed to touch screens, OLED displays and lighting, and sensors/detectors.
Dr. Reid said there are possibilities for inks based on silver nanofibers for the production of transparent conductive films for lighting and display applications, and inks based on silver nanoparticles for the production of electrodes, in, for example, photovoltaics.
Outside of thin film solar cell and displays, Mr. Ganslaw noted other significant markets for conductive inks.
“Other applications we are working on are proprietary due to NDAs with our customers,” Mr. Ganslaw said. “Historically, conductive inks continue to be used in medical devices, membrane switches, EMI/RFI shielding and electronic component manufacturing.”
“Besides solar panels, we will see an increase in sales of conductive inks that will help people perform interactive functions faster and better,” Mr. Toyama said. “Membrane switches are the core of our business, but we continue to look for ways for companies to develop new inks for new markets.”
“We are seeing some interesting opportunities in the area of sensors and in transparent conductive films,” Mr. Jablonski said. “There is also a great deal of interest from the MTS community on not only the new switch technologies, but also for the potential of saving money in current products due to the high cost of silver.”
“Conductive inks have given the printed electronics market a boost in the area of circuit pattern formation for various solar cells, RFID antennae and displays,” Mr. Nomura said.
ePackaging provides an excellent opportunity for Sun Chemical, which is one of the largest ink manufacturers in the world.
“We are uniquely positioned in the market, as we work closely with the converters and brand owners,” Mr. Bjorlin said.
Mr. Gordon said that conductive inks have been used in a wide variety of applications for more than 40 years, and DuPont Microcircuit Materials currently offers hundreds of commercial PE products to a global customer base.
“Likewise, the primary markets for the conductive inks have evolved over that time,” Mr. Gordon added. “Historically, automotive and military/defense were the key markets for DuPont products in the 1980s, largely due to the high reliability requirements of Hybrid ICs on ceramic substrates. Those applications still exist today, but over the past 10 years we have seen displays and photovoltaics become major areas of focus for our business. The resulting increase in volume and batch size demands have led us to further expand our global manufacturing operations, and this has positioned us well to succeed as the next generation of market segments emerge.”
Technical demands on conductive inks are challenging, and add to that the need for costs to be kept relatively low, conductive ink manufacturers have to place a major emphasis on R&D.
The cost of metals, particularly silver, is impacting formulations.
“Creative Materials had developed conductive inks that contain a lower percentage of silver while maintaining very high conductivity,” Mr. Ganslaw said. “As the price of silver continues to escalate, the market pressures increase for low cost highly conductive inks. We are already offering more than 10 formulations with lower silver content than conventional inks. Silver has increased by more than six times over the past seven years.”
“Our customers are frequently asking for materials that can offer them an improved cost position or unique properties that can help enable new and innovative applications,” Mr. Gordon reported. “As an example, the increased cost of precious metals over the past few years has led to a desire to either reduce the overall material usage through thinner/narrower printed lines, eliminate/replace precious metals with other low cost conductors, or both. Silver remains the most common precious metal for PE today, as it is still a high performance and cost effective material that cannot easily be replaced without sacrificing other important properties. The ink manufacturers are also being asked to develop or expand other classes of materials that provide more function than simple conductor traces. Examples include materials for heaters and sensors.”
“Reduced costs are the primary driver, but the move to digital printing (increased flexibility), low cost/low temperature/flexible substrates and faster processing (laser curing v. thermal oven, for example) are seen as big positives,” Mr. Clark said.
Ms. Boone pointed to the need for high-quality films - including film thickness uniformity, high transparency and functional performance, as well as compatibility with high-speed commercial coating methods such as slot die and ink jet printing, as needs.
Dr. Reid said that low temperature sintering with improved conductivity, is key, and in the case of transparent conductive applications, improved sheet resistance in combination with good optical properties.
Finer features are an important need for PE.
“Printed electronics is always looking for finer lines with better conductivity,” Mr. Toyama noted. “I think it will come down to a compromise between the finest lines and the reality of production yields and costs. Screen printing is the standard and is the most production friendly process on the market today. My opinion is that nozzle and inkjet dispensing is expensive until the cost of nano inks come down even more. I like the new sintered, low temperature conductive inks coming into the market and it will be interesting to see how they improve this technology.”
“Ultra-fine circuit patterning (line widths around 50um) by the screen print method, which until now was considered an impossible feat, in addition to on-going improvements in productivity yields, has given rise to advances in screen printing equipment, printing plates and paste refining,” Mr. Nomura said. “Printing is now serving as an alternative method to ultra-fine pattern formation, capable of performance levels that had only been achieved by conventional photolithography and etching methods in the past.”
“There is a strong push for finer features and possible replacement materials for ITO,” Mr. Jablonski said. “Obviously, lower cost without losing performance is always a focus.”
“There are growing needs for stable productivity yield of ultra-fine (50um) pattern formations and to reduce temperatures and speed of the curing process,” Mr. Nomura said.
Mr. Farnsworth said that customers are trying to understand the benefits and differences among inks currently on the market, and at the same time, trying to develop firm requirements.
“Many customers are still at an exploratory phase, and do not yet have firm ink requirements,” Mr. Farnsworth added. “As a result, we spend a lot of time in an educational mode, helping people understand performance factors beyond conductivity, such as adhesion. This is one reason we support the generation of common standards, to form a reference point for subsequent application-specific discussions. Another part of the discussion is to understand from our clients how their ink needs mesh with their other needs, including substrates and processing.”
Mr. Bjorlin said that Sun Chemical’s expertise in a wide variety of materials and printing processes, ranging from conductive inks to barrier coatings, offers major advantages.
“Sun Chemical has substantial investments in advanced metallization materials and barrier technology, and we are investing in R&D in areas that could will drive efficiencies,” Mr. Bjorlin said. “My view is that there is a lot of commonality in what needs to take place throughout the PV segments, from c-Si to thin film. For example, there is a need to react with new material sets that are compatible with new process’s and methods of manufacture, and we see room to make improvements. We are working on advanced materials, including transparent conductors, graphite and silver inks. Our digital ink jet program for electronics in the UK is also a huge asset for us and brings together options for how materials are dispensed.
“In the c-Si PV segment, advanced metallization and new process’ such as selective emitter is driving past 18% efficiencies in PV,” Mr. Bjorlin continued. We are focusing our efforts on the backside of the c-Si PV cell and believe we can generate significant improvements in yields and efficiencies through advancements in our Al back side and Ag tabbing pastes.
“Beyond c-Si PV, when people think of printed electronics, they think of printed conductors and dielectric materials, but it can go to a whole new dimension when it comes to high-speed manufacturing for new platforms in thin film PV including CIGS, CDTE and OPV,” Mr. Bjorlin noted. “Advancement in barrier coatings, for example, can enable these processes by increasing reliability and exposure to harsher environments, and what we’re doing on advanced materials systems will translate to other platforms such as displays and printed batteries.”
New Products for the PE Market
In order to meet the needs of their customers, conductive ink manufacturers ar focusing their R&D efforts on a wide range of areas.
“We work with our current customers and have led some of them into new markets that didn't exist last year,” Mr. Toyama said. “These new inks are under NDA and can't be revealed yet.”
“Plextronics is focused on developing new solution-processed inks for OLED displays and lighting, including solvent-based hole injection layer (HIL) and hole transport layer (HTL) inks,” Ms. Boone said. “These inks are designed to deliver improved device performance with today’s leading emitter technologies while enabling high throughput manufacturing.”
“Creative Materials is developing a line of products that can produce very fine lines down to 50 microns wide via screen printing,” Mr. Ganslaw said. “New applications require fitting several conductive traces into a narrow area.We already have two commerical products sold into these applications.”
“Toyo Ink has expanded our conductive ink lineup for ultra-fine, low-temperature and low-resistivity, and UV curing applications,” Mr. Nomura said. “We are also working to develop systems that simulate low resistivity properties characteristic to those of silver.”
“We continue to work on a new generation of screen inks that will print 25-50 micron features,” Mr. Jablonski said.
“We are working on multi-modal silver particle dispersions in combination with sub-nanometer silver clusters, which can be used to prepare conductive inks with improved particle packing resulting in higher conductivity, in combination with lower sintering temperatures,” Dr. Reid noted.
“We are due to launch a new copper screen print paste designed for a wider range of substrates than our current product – Intrinsiq CP-002,” Mr. Clark said. “We also aim to offer curing systems at some point this year to enable the use of our inks – the timescale here is not firm yet.”
“DuPont continues to work closely with its direct customers, as well as the downstream OEMs, in an effort to define and anticipate the future market demands for new material developments,” Mr. Gordon said. “While we cannot disclose specifics about our developments, to protect the confidentiality of our programs, we continue to fund research into new areas that will expand our overall portfolio to provide a differentiated offering.”
Expectations for the Coming Years
Overall, conductive ink manufacturers see plenty of opportunities for printed electronics to move into mainstream commercial applications.
“I think printed electronics as a technology type will continue to grow, though it is tough to predict the pace,” Mr. Farnsworth said. “It is also difficult to predict the application(s) which will take the next lead in driving not just trade show interest, but product sales including inks. What we are seeing, though, is that interest in printed electronics is propagating through existing industry trade shows. Topical, long-standing conferences from electronics to photovoltaics to printing to industrial coatings now have special sections to address issues and opportunities around additive manufacturing and functional, printed electronics.”
“ECM will grow in markets that serve low cost, high volume devices that utilize screen printing of conductive inks,” Mr. Toyama said.
“Our expectations for printed electronics is that our development activities over the past three to four years will become commercial successes over the next 18 to 24 months,” Mr. Ganslaw said.
“We feel strongly that the printed electronics market will continue to grow as new functional materials and print and deposition methodologies become available to produce the new product concepts on the horizon,” Mr. Jablonski said.
Mr. Nomura said that Toyo Ink believes printed electronics will expand on many fronts in the coming years.
“Mobile handsets, displays and lighting continue to shrink in size, and the printing method is gaining ground as the more economical process in forming various circuit interconnects on a large and stable scale,”Mr. Nomura added.
“We expect to see OLEDs expand to large-area applications such as televisions,” Ms. Boone said. “OLED lighting is still maturing, but additional niche applications will continue to enter the market over the next few years.”
“While the predictions from IDTechEx and others may be ambitious, printed electronics is going to grow and grow over the next 20 or more years and dominate the electronics landscape,” Mr. Clark said. “Conductive inks are only the start. The ability to print components and semiconductors in particular will also be key.”
“We see technical challenges being overcome and greater integration through supply chains, leading to large scale commercialization, maybe even approaching the scale predicted by numerous market research reports,” Dr. Reid said.
“The PE market is not for the faint of heart, but I’m very optimistic about our opportunities in printed electronics,” Mr. Bjorlin concluded. “I think we have a winning plan. The technology packages we are putting together have a home in multiple applications. These material sets are translatable, the volumes will be large and Sun Chemical is committed to supporting the business globally.”
“This is an exciting time for printed electronics,” Mr. Gordon concluded. “Several of the newly commercial applications will expand their penetration within other OEMs, plus it is our belief the “Killer Applications” will arrive once the remaining technology, production and cost hurdles are overcome. These new growth areas will require both global technology platforms and manufacturing base to ensure success.”