New Photovoltaics and Printed Electronics by Ink-jet - Japan/USA
New opportunities for printing electronics include: polymer solar film (pictured left); flexible polymer-based lighting; electronic books printed polymer backplanes; transparent solar cells; flexible electronics and batteries; paper-like products; disposable diagnostic devices; intelligent packaging and large area electronics.
That was the message of Fujifilm Dimatix at the world’s largest conference and exhibition on printed electronics in Dresden Germany in April. This was the Printed Electronics Europe event of IDTechEx. It will now be leapfrogged by the sister event Printed Electronics USA in San Jose, CA being even bigger.
Chuck Griggs, VP Applications Engineering of Fujifilm Dimatix, Inc. saw the advantages of inkjet as non-contact and drop on demand and it reduces both materials processing and environmental impact. Printheads and fluids developed in tandem for specific application requirements. R&D metrics are directly translatable to production protocols.
IDTechEx notes that the hottest topic among these is currently photovoltaics (PV) with the new photovoltaics beyond conventional silicon offering the ability to be tightly rolled, transparent, work off both heat and light etc creating a multibillion dollar market in only a few years from now. That is why IDTechEx is staging the conference Photovoltaics Beyond Conventional Silicon in Denver in June 2008 with visits to the world class work being carried out in that region, optional masterclasses and an exhibition. Top class speakers are being flown in from all over the world.
Remarkable event not to be missed
This remarkable event will not be burdened by discussion of the old crystalline and amorphous silicon technologies. It will cover the better performing and increasingly lower cost new technologies such as CdTe, DSSC, CIGS and organic. Indeed, CdTe photovoltaics, which is thin film but not yet printed, has attracted 1.5 billion dollars in orders in the last few months alone. The other technologies can already be printed and some are in production in the USA, UK, Germany and Japan, with much more to come. This subject is extremely exciting and it will lead to many innovative new products exploiting such things as invisible solar power on watches, packages and medical disposables for example.
The macro features of inkjet include:
• Print accuracy > 20 microns
• Drop volume > 10 pL
• High throughput
• High print speed
• High throw rate of ink
This leads to typical applications being:
• Bio and Chemical Sensors
• Solar Cells
• Dielectric Coating
• Photo Resist
• Adhesives
The key enabling attributes of ink jet were cited as:
• Full production speed (over 100m/min)
• Single pass imaging
• Non-contact
• Wide variety of fluids and inks
• Reliable performance
Photovoltaics is easiest because conductive traces only need to be better than 75 microns whereas for backplanes they need to be ˜ 20 microns. Organic TFTs need fine feature size 10 pL drops and 40-100 micron line width depending on fluid, substrate, and spot density with 1pl drops 15 - 30 micron line depending on fluid, substrate, and spot density.
Increasingly, devices combine organic and inorganic materials, as with the Dye Sensitized Solar cells DSSC inkjet printed reel to reel in the UK and the biosensor that has been made by Fujifilm Dimatix.
By Dr Peter Harrop
