From Nanowires to Printed Electronics

Nanotechnology is a multidisciplinary field that has many potential applications. In time more and more nanotechnological applications are emerging. We are familiar with sun-block creams based around oxide nanoparticles, self cleaning windows with unique surface coatings that break down dirt and more powerful tennis racquet frames containing carbon nanotubes. Computer chips now host insulating layers that are only few atoms thick. Yet, the full potential on nanotechnology is still far from being achieved. Indeed, there is a huge scope for nanoscience to enter our lives. Flexible electronics is one of the areas where it can be realised. So far in the first generation of flexible displays, the switching of the pixels is performed by plastic or organic semiconductor transistors. Due to their intrinsic plasticity, these semiconductors are favoured over traditional rigid single crystal silicon technology. Despite significant effort in organic electronic research, plastic transistors are slow and struggle to perform in circuits and also in current - driven applications.One of the ways to overcome this problem is to use solution processable inorganic semiconducting nanowires formulated into functional inks. These inks could be deposited by simple solution-coating methods onto flexible plastic substrates to produce semiconducting layers for electronic devices. The main goal of the proposed project is to demonstrate feasibility of printable high performance flexible electronic devices, such as field-effect transistors and simple circuit demonstrators. Successful demonstration of these printable devices is expected to make a breakthrough in novel electronic applications including high resolution flexible displays, RFIDs, integrated display drivers, chemical and biological sensors, nano-scale photodetectors, printable lasers and solar cells. In medical applications, ordered arrays of nanowires can be integrated into pace makers to generate electricity from muscle movements and thus eliminate the need for replaceable batteries. The printing approach will open up possibilities for fast prototyping of custom-made circuits that could be directly ink-jet-printed from a computer design layout onto lightweight and flexible substrates.There are endless possibilities for the research in printable nanomaterials and devices, extending to the areas of environment monitoring, health care and energy generation.

The printed electronics field is addressing novel approaches in making consumer electronics and also applications that are just emerging. The main driving force behind printed electronics is the ability to fabricate electronic devices by additive printing processes that are substantially more economical and efficient compared to standard fabrication techniques. Industrial involvement is growing very rapidly in this area and the number of manufacturers for printed and potentially printed electronics in expected to reach 100,000 by 2020 [1]. Currently, over 10,000 organisations are interested in the field world-wide, out of which 1500 are involved in serious business activities. Europe hosts more than one third of these organisations (550)[1]. UK has been at the forefront of research, including novel organic semiconductors and devices, nanomaterials, and printing technologies including ink-jet printing, and currently hosts industry with interests including materials supply, printing machine manufacturers, flexible substrate development, technology development and device producers. The commercial private sector is going to benefit from the proposed research in both short and long terms. Our collaborators include manufacturers of materials, substrates and printing equipment. We have already established relations and put a number of agreements in place with these companies. Development of high performance nanowire materials and processes, including printable nanowire field-effect transistors at Surrey, will allow for appropriate intellectual property protection and efficient technology transfer to companies, which have the capability of industrial scale-up, process development and product marketing. Moreover, due to close links with industry at Surrey, a demonstration of commercialisation opportunities can receive a boost through KTA funding. The public sector is going to benefit from the proposed research in the longer term. Printed electronics address a varied range of opportunities that include Energy, Healthcare and Environment with applications such as solar power generation, flexible displays, smart packaging, sensor networks, large area lighting, stretchable electronics, biodegradable electronics, radically improved human interfaces and wearable electronics. Printed electronics is also promising to deliver a much smaller carbon foot print for manufactured devices due to a dramatic reduction of technological processing steps, much lower deposition temperatures and elimination of etching and rinsing chemicals during production. References 1. Xiao, N. and P. Harrop, Printed Electronics in East Asia, Market research report, 2009, IDTechEx Ltd.