TCM 2012: 4th symposium on transparent conductive materials

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Heraklion, Crete, Greece

Over the past few years, there has been an increase in interest in research and applications for transparent conductive materials (TCMs). Whether work is focused on optimization or even replacement in some cases of material platforms such as ITO, or the realization of a variety of cutting-edge applications in the fields of, among others, solar cells, sensors, electrochromic, thermochromic and smart windows, architectural coatings as well as in display technologies, innovative TCMs are regarded as the main candidates for the forthcoming "post-Si" electronics era. Following three successful prior events, the 4th instalment of the conference, TCM2012 took place in Crete in October 21-26, 2012. Over the course of the event, 300 attendees gathered and attended seminars, workshops and high quality presentations and poster sessions highlighting worldwide activities on the topic.

Titania: a truly versatile material

One of the most interesting points highlighted in the event was the tremendous interest in the properties of titanium oxide (TiO2, also known as titania). With a large range of applications, from paint to sunscreen or even food colouring, it is also used in several electronics applications. Some examples include:

•  It is the main nano-material choice in dye sensitized solar cells; sintered titania nanoparticles have been extensively used in these third generation photovoltaic technologies, forming the network of particles through which charge carriers are transported to the solar cell's electrodes.
• The fabrication of a microfluidics cholesterol sensor based on nanocrystalline anatase-titanium dioxide film deposited onto indium tin oxide glass has been demonstrated.

During the TCM 2012 conference, several other uses of titania were highlighted, including research that demonstrated how the use of titania nanoparticles in wet-processed ITO optimized performance and increased conductivity until a specific level of titania loading after which, the effect diminished. All that because nanoparticles of titania can fill the gaps between ITO nanoparticles and thus, optimize conductivity paths.

The importance of titania in photocatalysis was also discussed at the conference , with invited talks discussing how modified titanium oxide coatings can be utilized for photocatalytic applications of seld-cleaning devices and how many of the photocatalysts currently being developed utilize TiO2 as a key compound. With uses that could be applied in the disinfection of water, oxidation of organic comtaminants, self-cleaning surfaces where free radicals oxidize organic matter or even the decomposition of crude oil, we are bound to see the utilization of titanium oxide dramatically increase over the next few years, especially since it's also a very low cost material that's readily available. As a matter of fact, specialist chemicals and materials will reach over $50 billion in 2023 and titanium compounds are in the list of the most commonly used chemicals in the electronics industry, as described in the IDTechEx report "Most-Needed Chemicals for New Disruptive Electronics and Electrics" (www.idtechex.com/chemicals).

 

Commercialization considerations

The conference also included an afternoon of sessions on commercialization efforts and the status of different TCMs being developed not just in academic research institutes but also in company research programmes. Applied Materials for instance talked at the event, discussing their work on IGZO thin film transistors and how interface engineering between semiconductor and dielectric layers is critical, more than 70% of research effort.

Clark Bright with 3M also discussed his company's advances in the field of transparent conductors and highlighted the work on 3M's patented stack for increased transparency : ITO stacked with polymer SiO2 layers giving as a result an increase in transparency, lower reflectance and better sheet resistance. Mr Bright also commented on an interesting difference between current directions in the electronics industry and academia According to him, industry seems more focused on metal nano-structures and continuous metal films rather than graphene, carbon nanotubes or polymer TCs which are still at research stage and are attracting a lot of attention in academic research facilities. The most obvious reason for this differentiation of focus is the fact that metal nanostructures and metal films are currently better understood and closer to successful commercialization whereas other material systems need more basic research before being successfully transferred into commercial applications.

 

For more information on the topics of transparent conductive materials, attend IDTechEx's Printed Electronics USA 2012 in Santa Clara, CA, the biggest event in the world on the topic of printed electronics and allied technologies. For more information on the event, please visit www.idtechex.com/peUSA