Printed Electronics Overview

Printed Electronics

Way back in 2011 we looked at the state of Printed Electronics and concluded this was a rapidly emerging area of Technology and had been since the previous look at The Future of Low Cost Electronics Manufacture in 2009. It has been a while so what has happened since then?

 

Printed Electronics

Printed Electronics

This is another guest post by Andrew Walla.

 

Andrew Walla

Andrew Walla

Printed Electronics Overview

Rapid prototyping, also referred to as 3D printing or additive manufacturing is the process of building objects or devices by building up layer by layer [1]. It has been identified as a potentially disruptive technology in the manufacturing industry in the coming years and is particularly well suited to provide benefits to technologies that operate on smaller scales of production [2]. New manufacturing paradigms, such as direct manufacturing (directly printing the sold goods) and home manufacturing (providing the capability for consumers to produce parts themselves) are set to change the way that small manufacturing businesses operate and significantly increase the level of competition in the industry [3].

 

This post will discuss the manufacturing technique of printing – a technology whose origins date back more than five centuries [4] and in this time a number of different printing methods have been developed. Successive layers are generally printed onto a substrate either by direct contact; via an impression cylinder (such as in flexographic, graviture or offset printing), deposited via a stencil (screen printing); or directly deposited onto the substrate (for example, inkjet printing, aerosol-jet printing or organic vapor-jet printing). Of these technologies, inkjet printing is particularly well suited to rapid prototyping and low volume manufacturing due to its high customisability, relatively high resolution and relatively low set-up cost [1].

 

Inkjet printed electronics differs to conventional inkjet printing in that the deposited substances need to exhibit desired electronic behaviours. A common method to achieve this is to intersperse the ink (a solvent) with nano-particles (small particles with controlled sizes, typically in the order of nano-meters) with desired conductive, dielectric or semiconducting characteristics. The printed substance might be treated post printing in order to evaporate the solvent and/or facilitate a chemical change in the nano-particles. Examples of such treatment include thermal curing [5], curing by ultraviolet light [6], laser sintering [7], e-beam sintering [8], chemical sintering [9] or plasma sintering [10].

 

Current research efforts are focusing on improving the printing and post-processing technologies available [10-12], improved interconnects [13] and vias [14], improved semiconductors, and printing under less stringent conditions. Examples include printing conductors at room temperature [6] and printing elements such as transistors [15] and diodes [16] with ever increasing performance characteristics. It is forecast that these improvements will continue for some time, as the fastest known inkjet printed transistor has an operating speed of around 20MHz [17-18]. (This is several orders of magnitude behind the capability of existing silicon chip technology.) Researchers are also working on developing transistor characteristics other than maximum frequency. For example, inkjet printing technology has been used to produce flexible and transparent transistors [19].

 

For those looking to predict where printed electronics will have the greatest future impact, it may pay to think outside the box. In the author’s opinion, inkjet printing technology is likely to play a larger role in enabling new applications than it is to replace existing electronic technology. It is unlikely that a device with the functionality of a smartphone will be printed any time soon, but perhaps the capability of printing your own solar panels is closer than you think.

 

[1] N. Saengchairat, T. Tran and C.-K. Chua, “A review: additive manufacturing for active electronic components,” Virtual and Physical Prototyping, vol. 12, no. 1, pp. 31-46, 2017.
[2] A. O. Laplume, B. Petersen and J. M. Pearce, “Global value chains from a 3D printing perspective,” Journal of International Business Studies, vol. 47, pp. 595-609, 2016.
[3] T. Rayna and L. Striukova, “From rapid prototyping to home fabrication: How 3D printing is changing business model innovation,€” Technological Forecasting & Social Change, vol. 102, pp. 214-224, 2016.
[4] S. H. Steinberg, Five hundred years of printing, Maryland: Courier Dover Publications, 2017.
[5] N. Graddage, T.-Y. Chu, H. Ding, C. Py, A. Dadvand and Y. Tao, “Inkjet printed thin and uniform dielectrics for capacitors and organic thin film transistors enabled by the coffee ring effect,” Organic Electronics, vol. 29, pp. 114-119, 2016.
[6] G. McKerricher, M. Vaseem and A. Shamim, “Fully inkjet-printed microwave passive electronics,” Microsystems & Nanoengineering, vol. 3, p. 16075, 2017.
[7] S. H. Ko, H. Pan, C. P. Grigoropoulos, C. K. Luscombe, J. M. J. Fréchet and D. Poulikakos, “All-inkjet-printed flexible electronics fabrication on a polymer substrate by low-temperature high-resolution selective laser sintering of metal nanoparticles,” Nanotechnology, vol. 18, pp. 1-8, 2007.
[8] Y. Farraj, M. Bielmann and S. Magdassi, “Inkjet printing and rapid ebeam sintering enable formation of highly conductive patterns in roll to roll process,” The Royal Society of Chemistry, vol. 7, pp. 15463-15467, 2017.
[9] S. Wunscher, R. Abbel, J. Perelaer and U. S. Schubert, “Progress of alternative sintering approaches of inkjet-printed metal inks and their application for manufacturing of flexible electronic devices,” Journal of Materials Chemistry C, pp. 10232-10261, 2014.
[10] Y.-T. Kwon, Y.-I. Lee, S. Kin, K.-J. Lee and Y.-H. Choa, “Full densification of inkjet-printed copper conductive tracks on a flexible substrate utilizing a hydrogen plasma sintering,” Applied Surface Science, vol. 396, pp. 1239-1244, 2017.
[11] J.-J. Chen, G.-Q. Lin, Y. Wang, E. Sowade, R. R. Baumann and Z.-S. Feng, “Fabrication of conductive copper patterns using reactive inkjet printing followed by two-step electroless plating,€” Applied Surface Science, vol. 396, pp. 202-207, 2017.
[12] H. Ning, R. Tao, Z. Fang, W. Cai, J. Chen, Y. Zhou, Z. Zhu, Z. Zeng, R. Yao, M. Xu, L. Wang, L. Lan and J. Peng, “Direct patterning of silver electrodes with 2.4 lm channel length,€” Journal of Colloid and Interface Science, vol. 487, pp. 68-72, 2017.
[13] T. Ye, L. Jun, L. Kun, W. Hu, C. Ping, D. Ya-Hui, C. Zheng, L. Yun-Fei, W. Hao-Ran and D. Yu, “Inkjet-printed Ag grid combined with Ag nanowires to form a transparent hybrid electrode for organic electronics,” Organic Electronics, vol. 41, pp. 179-185, 2017.
[14] T.-H. Yang, Z.-L. Guo, Y.-M. Fu, Y.-T. Cheng, Y.-F. Song and P.-W. Wu, “low temperature inkjet printing and filling process for low resistive silver TSV fabrication in a SU-8 substrate,” 30th IEEE International conference in Micro Electro Mechanical Systems (MEMS), 2017.
[15] J. Roh, H. Kim, M. Park, J. Kwak and C. Lee, “Improved electron injection in all-solution-processed n-type organic field-effect transistors with an inkjet-printed ZnO electron injection layer,” Applied Surface Science, vol. 420, pp. 100-104, 2017.
[16] K. Y. Mitra, C. Sternkiker, C. Marti­nez-Domingo, E. Sowade, E. Ramon, J. Carrabina, H. L. Comes and R. R. Baumann, “Inkjet printed metal insulator semiconductors (MIS) diodes for organic and flexible electronic application,” Flexible and Printed Electronics, vol. 2, no. 1, p. 015003, 2017.
[17] X. Guo, Y. Xu, S. Ogier, T. N. Ng, M. Caironi, A. Perinot, L. Li, J. Zhao, W. Tang, R. A. Sporea, A. Nejim, J. Carrabina, P. Cain and F. Yan, “Current Status and Opportunities of Organic Thin-Film Transistor Technologies,” IEEE Transactions on Electron Devices, vol. 54, no. 5, pp. 1906-1921, 2017.
[18] A. Perinot, P. Kshisagar, M. A. Malfindi, P. P. Pompa, R. Fiammengo and M. Caironi, “Direct-written polymer field-effect transistors operating at 20MHz,” Scientific Reports, vol. 6, pp. 1-9, 2016.
[19] L. Basirico, P. Cosseddu, B. Fraboni and A. Bonfiglio, “Inkjet printing of transparent, flexible, organic transistors,” Thin Solid Films, vol. 520, pp. 1291-1294, 2011.

 

Andrew Walla, RF Engineer, Successful Endeavours

So there has been some substantial change but we aren’t yet at the point where this type of Electronics Design and Manufacture has begun to significantly disrupt the mainstream industry. But I can imagine the day when some of what I do now can be printed and tested right now on my desk instead of having to go through PCB Design, PCB Manufacture and Electronics Prototyping first. Can’t wait for Printed Electronics to become mainstream.

 

Successful Endeavours specialise in Electronics Design and Embedded Software Development, focusing on products that are intended to be Made In Australia. Ray Keefe has developed market leading electronics products in Australia for more than 30 years. This post is Copyright © 2017 Successful Endeavours Pty Ltd.

 

 

LED Lighting To Finally Become Cost Effective

LED Lighting

10 years ago, LED Lighting was set to revolutionise the general illumination market. LEDs, also known as Light Emitting Diodes, had already taken over are the role as indicator panel illuminators and user interfaces on industrial, commercial and consumer products. All the trend lines indicated that they would eclipse the incandescent light globe for cost per watt within a decade.

So what went wrong?

Purple LED Diffused

LED Lighting – Purple LED Diffused

More power without more light

As the technology was scaled up, the power levels rose and the expected requirements of more heatsinking were being dealt with and all seemed on track for LEDs to take over the world of lighting. But then a snag was hit. The technology got to a point where the efficiency dropped off as more current flowed through the diode. Companies like CREE, LumiLEDs and OSRAM pursued different and moderately successful strategies to try and overcome these limitations but the pace of progress slowed dramatically.

All of this points to a technical barrier we still don’t fully understand but are chipping away at.

 

Same light less cost

The other issue is the cost per watt in terms of the manufacturing cost of LEDs. The manufacturing process typically uses Sapphire or Silicon Carbide substrated which makes LEDs more expensive to manufacture than conventional semiconductors. There are several ways to improve this and they are all being pursued in parallel.

The first is the move toward organic semiconductors as covered in my recent post on Printed Electronics I looked at much lower cost techniques for making semiconductors and organic LEDs are one of the possible end products from these techniques. The CSIRO are world leaders in these technologies and are actively pursuing research into flexible electronics including organic displays and lighting. Here the challenge is creating a robust manufacturing technique that produces high volume, low cost lighting. The efficiency may not be as high but the cost per watt is much lower. Organic Semiconductors and organic LEDs will continue to be part of the solution. You can read about their efforts in CSIRO Flexible Electronics.

CSIRO Flexible Electronics

CSIRO Flexible Electronics

The second move is toward reducing the costs of conventional LED manufacture by eliminating the more costly steps of the process. A recent breakthrough was announced by Bridgelux and reportied in IEEE Spectrum will permit the manufacture of LEDs on silicon substrates. In Silicon Is Key to Quest for $5 LED Lightbulb the breakthrough is described and the promise is good. This also does not address the efficiency problem but again reduces the cost per watt.

Bridgelux Silicon Substrate LED

Bridgelux Silicon Substrate LED

Efficiency is the final frontier

The final chapter is yet to be written because the breakthrough we have all hoped for has not yet arrived. In the meantime the problem is being tackled from many sides and advances are being made on multiple technical fronts. LED lighting is an important part of the strategy to reduce our Carbon Footprint.

 

Ray Keefe has been developing high quality and market leading electronics products in Australia for nearly 30 years. For more information go to his LinkedIn profile at Ray Keefe. This post is Copyright © 2011 Successful Endeavours Pty Ltd.

Printed Electronics

Printed Electronics – A New Roadmap

The direction of Printed Electronics has taken an interesting new turn with the focus being no longer only on reducing production cost. Now the electronics industry is looking at product ideas that were previously thought to be impossible.

Printed Electronics

Printed Electronics

Some examples from The Future Of Printed Electronics shows previously unanticipated applications such as:

  • Nokia is developing Flexible Electronics that stretch
  • Companies such as Novacentrix are developing methods to directly Print Copper
  • Solar Cell electrode printing

The previously expected driver of Low Cost Electronics Manufacture is no longer the primary goal. Some of the above methods do reduce cost but the emerging trend is toward new product opportunities. This makes sense as markets tend to emerge and go through cycles until they are so commoditised that cost is the primary issue. We are at the beginning rather than the end of this cycle for Printed Electronics.

 

Printing of Organic Transistors and Organic PhotoVoltaic Solar Cells is still on the agenda so the market is diversifying in several interesting directions at the same time.

 

Ray Keefe has been developing high quality and market leading electronics products in Australia for nearly 30 years. For more information go to his LinkedIn profile at Ray Keefe. This post is Copyright © 2011 Successful Endeavours Pty Ltd.