Silver nanowires conduct electricity 4,000x better than nanoparticles and don't require heat.
To get good electrical signal conductivity, engineers use to heat nanoparticles until they melted together, which would burn up thinner materials like paper, fabric, etc. This meant only thicker, heat resistant, and more expensive materials could be made into electronics.
Thanks to researchers from Duke University, now flexible electronics can be made much cheaper, more effective, and on almost anything. Ironically, the solution turns out to be rather simple. Simply changing the shape of the nanoparticles in the ink eliminated the need for heat.
They tested silver nanosphere, short and long nanowire, and microflake exposed to different temperatures to create the best conductive films from the ink compounds. Tests on the different films them showed that electrons flowed easier through films made of silver nanowires than those made of nanospheres or microflakes.
The "Aha!" moment wasn't the finding the best form but in learning how much more conductive nanowires were to nanoparticles: 4,000 times greater!
They’re currently studying whether silver-coated copper nanowires, a cheaper alternative to pure silver nanowires, will deliver the same effect as a part of that effort, and they’re also experimenting with aerosol jets as a method of printing silver nanowire inks in usable circuits.
Silver + Graphene = WOW
Even better than silver plating copper, is balancing the weaknesses of silver with the strengths of graphene. Other researchers have been experimenting with combinations of super conductive silver nanowires and super thin yet extremely durable graphene.
It is the strongest material ever tested, efficiently conducts heat and electricity, and is nearly transparent. However, it is also very expensive to make, so a hybrid combo seems to be a great solution.
"The addition of graphene to the silver nanowire network also increases its ability to conduct electricity by around a factor of ten thousand," says Alan Dalton, head of the team behind this new material. "This means we can use a fraction of the amount of silver to get the same, or better, performance. As a result screens will be more responsive and use less power."
"One of the issues with using silver is that it tarnishes in air," says Matthew Large, lead researcher on the project. "What we've found is that the graphene layer prevents this from happening by stopping contaminants in the air from attacking the silver. What we've also seen is that when we bend the hybrid films repeatedly the electrical properties don't change, whereas you see a drift in the films without graphene that people have developed previously. This paves the way towards one day developing completely flexible devices."
Endless Silver Nanowire Possibilities
Duke University researchers are excited to develop technologies with these super conductive silver nanowires. They expect these to improve photovoltaic solar cells, touch-screens, pressure sensitive devices, LEDs, batteries, and even bio-electric devices. They will be exploring aerosol jet 3D printing of such metal foams for uniquely customizable and versatile applications.
Using nanowires as building blocks, the silver aerogels don't have traditional rigid limitations. They even have tunable densities, controlled pore structures, improved electrical conductivity and mechanical properties, making them uber practical for any application.
"The high porosity and excellent mechanical/electrical properties of these silver nanowire aerogels may lead to enhanced device performance and open up new possibilities in fuel cells, energy storage, medical devices, catalysis and sensors," said Fang Qian