Defence of dissertation in the field of Engineering Physics, Alexey Tsapenko, M.Sc.

The title of the dissertation is "Enhancing Optoelectronic Performance of Randomly Oriented Single-Walled Carbon Nanotube Films".

Precise tuning of optical and electrical properties of single-walled carbon nanotubes opens a new avenue for traditional and flexible optoelectronics.

The market introduction of foldable and bendable screens boosted the development of effective material solutions for enabling the next generation display products of almost any form, shape, and size.

Single-walled carbon nanotube films are among the strongest candidates for the replacement of a key material of all sorts of thin but rigid panels we currently have around us. While the flexible and stretchable nanotube-based films can outperform the most commonly used metal oxide ones such as indium-doped tin oxide (ITO) films, they still have to reach their high transparency and conductivity values.

This dissertation reveals novel modification approaches to make the nanotube films as conductive as possible while keeping their transparency at nearly the same level as their direct competitors. The first technique utilizes the synergetic effect of both nanotubes and graphene to uncover the potential of such a hybrid material. The second one is devoted to the optimization of a widely used modification technique with chemical elements, where their correct selection with the proposed optimization leads to unprecedented optical and electrical values. The final one presents an approach based on a tiny droplet deposition right on top of the nanotubes for a controllable and reproducible adjustment of their highly desirable optoelectronic performance even at meter-scale film dimensions. Along with the techniques, the optical properties were extensively studied using optical spectroscopies to understand the nanotube fundamental parameters.

As a consequence, each of these cases leads to the creation of films that exhibit superior properties and state-of-the-art performance.

Opponent: Professor Alexander Okotrub, Novosibirsk State University, Russia

Custos: Professor Esko I. Kauppinen, Aalto University School of Science, Department of Applied Physics

Supervising professor: Professor Esko I. Kauppinen, Aalto University School of Science, Department of Applied Physics

Co-supervisor: Professor Albert Nasibulin, Skolkovo Institute of Science and Technology, Russia

Electronic dissertation: http://urn.fi/URN:ISBN:978-952-60-8738-2

Contact information: Alexey P. Tsapenko, Department of Applied Physics, +7 916 650-41-09, [email protected] ([email protected])

The dissertation is publicly displayed 10 days before the defence at the noticeboard of the School of Science in Konemiehentie 2, Espoo.