Tomáš Homola from DPE received a new MUNI award for innovative scientific research

Good afternoon, Tomáš. I offer congratulations to you on your MUNI Innovation Award. You have received this award for the application of plasma surface modification in the field of printed electronics and its application in the industry. From where came the idea for the application of plasma surface modification for printed electronics?

I came across this topic during my Ph.D. studies when I was an intern in a private company in Singapore in 2011 and 2012. I worked there on the calibration of a plasma source for an experimental roll-to-roll production line that manufactured large-area flexible foils with functional semiconductor layers.

After my Ph.D. studies, practically straight from Singapore, I applied for a post-doc position at Masaryk university and I continued my work in this field here. In 2016, mainly with collaboration with doc. Petr Dzik from the Faculty of Chemistry of BUT, we came up with a concept for plasma-modified semiconductor layers that could be used for cheap manufacturing of large-area solar cells using roll-to-roll processing.

I was given an opportunity to develop this idea further thanks to two PoC grants from the MUNI Transfer Technology Office. One of the conditions for approval of the PoC grant was to acquire a Letter of Intent (add4) from commercial companies that do business in the research field. In 2017, it was said company Saule Technologies that provided me with a Letter of Intent. Since 2018, I was able to successfully work on my first PoC project and inform the said company of technological innovations in the studied field.

In what way do plasma applications modify large-area printed solar cells?

Department of Physical Electronics has a long and ongoing tradition in the development of new atmospheric plasma sources that find their use in industry. The basic principle is the creation of a plasma that is thermally unbalanced. It means that the plasma contains high-temperature electrons while other heavier particles have a lower temperature. It is because of this that plasma cannot damage the volume of the applied material, but does significantly alter the surface of the applied material.

The simplest application is an effective surface cleaning of various semiconductors before adding new overlapping layers. Impurities in the form of nano-contaminants do not create an obstacle for good homogeneity of film from the optical view but for example, deteriorate the optoelectronic properties such as the work function and therefore influence the transfer of electric charge carriers between layers negatively.

Semiconductor cleaning is traditionally done by acid or alcoholic baths or by a combination of UV radiation and ozone, which requires tens of minutes. We can do this process in seconds by using plasma. At the same time, the outcome products such as solar cells or OLED displays have the same performance parameters.

The main advantage of plasma application is the way how this process is integrated into production. It can be directly incorporated into a roll-to-roll manufacturing line with the use of fast plasma sources. These roll-to-roll lines are used for printing functional layers on flexible, cheap, and often thermally sensitive electronics which further find use in new products such as third-generation solar cells. Saule Technologies manufacture solar cells in the form of thin foil that can be sticked to windows.

How did you manage to establish cooperation with the company Saule Technologies?

In this case, the focal point of the cooperation was the supply of plasma technology into the manufacturing line. This was done through the company Roplass. Roplass is a spin-off company of Masaryk University. It was founded by the director of R&D center CEPLANT prof. Mirko Černák with the intent to boost the commercialization of scientific outcomes.

Positive presentation of our results on various international technological expositions led to important contacts that we used with proper timing with companies to incorporate new products with the change in manufacturing processes. Other collaborations are done in the same way. The most vital is the scientific research done here at MUNI where we solve projects with various foreign or Czech companies and we help them with the incorporation of new technologies into production.

I assume that more colleagues and students were working with you on this research. How big was your team?

Specifically, in this research on plasma modification for printed flexible electronics, I was accompanied by only a small group of students. The more important role play my colleagues from other institutions with which we collaborate, e.g. BUT in Brno or STU in Bratislava. For example my colleagues from BUT doc. Petr Dzik and dr. Jan Pospíšil help us chemically prepare the composition and subsequent printing of the films, they helped with the creation of the prototype and with solar cell tests. All this needs an equipment infrastructure that MUNI does not have nor need due to excellent collaborations. Thanks to this we can focus on MUNI primarily on the development of plasma sources, their diagnostics, and search for their other protentional applications.

What are you working on now? Do you continue with the collaboration and further enhance new procedures or are you working on some other new hot topic?

We experiment on the mineralization of mesoporous nanolayer on the TiO₂ base, perovskites, graphene, and other new 2D nanomaterials such as MXenes and others.

Plasma-modified layers with structured nanomaterials have new optoelectronic properties, better stability and we test these layers in various applications. Next to classical optoelectronic applications, we reached good results in the field of photocatalytic cleaning of wastewater using nanomaterials. We can eliminate even very low concentrations of pollutants and biological contaminants that cannot be thoroughly removed by other methods. We are working on this topic with our colleagues from Finland, Spain, and also Bratislava.

Thank you for the interview, Tomáš. I wish you success in your scientific research.

Mgr. Tereza Schmidtová, Ph.D.