The doctoral dissertation in the field of Physics will be examined at the Faculty of Science, Forestry and Technology, Joensuu campus.
What is the topic of your doctoral research? Why is it important to study the topic?
My doctoral research focuses on enhancing the photoluminescence efficiency of single-walled carbon nanotubes (SWCNTs) through the incorporation of artificial traps. This topic is crucial because SWCNTs possess unique optical and electronic properties that hold immense potential in various fields, including telecommunications, quantum technologies, and biosensing. However, their low photoluminescence efficiency limits their practical applications. By investigating methods to localize photoexcited excitons within these nanotubes, my research aims to address this challenge, paving the way for the development of advanced optoelectronic devices.
What are the key findings or observations of your doctoral research?
The key findings of my research include the identification of new quantum states and energy levels resulting from the interaction of SWCNTs with HCl and oxygen. Notably, I discovered that excitons can be localized in proximity to hydrogen adatoms, leading to significant changes in their excitation and recombination energies. This research provides novel insights into exciton-trap interactions and offers an innovative approach to increase photoluminescence intensity by more than twofold through oxygen functionalization. These findings contribute to the understanding of quantum defects in one-dimensional systems and hold great promise for future applications, such as developing nanolasers and single-photon sources.
How can the results of your doctoral research be utilised in practice?
The results of my doctoral research can be utilized in various practical applications, including the design of more efficient optoelectronic devices, such as nanolasers and single-photon sources for quantum communication. The improved methods for integrating artificial traps into SWCNTs may also enhance the performance of these materials as fluorescent markers in biomedical imaging. By increasing the photoluminescence efficiency of SWCNTs, my research opens new avenues for their use in advanced technologies and materials science.
What are the key research methods and materials used in your doctoral research?
My doctoral research employed a combination of experimental techniques, including ultrafast transient absorption spectroscopy, photoluminescence spectroscopy, raman spectroscopy and optical absorption spectroscopy. The study involved non-covalent doping of SWCNTs with HCl and covalent functionalization with oxygen to create localized exciton states. By analyzing the optical properties of the modified SWCNTs, I investigated the impact of these modifications on exciton behavior and energy levels. The research also included simulations to understand the fundamental processes occurring within these unique structures.
The doctoral dissertation of Timofei Eremin, MSc, entitled Exciton dynamics in functionalized carbon nanotubes be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus. The opponent will be Professor Harri Lipsanen, Aalto University, and the custos will be Professor Jyrki Saarinen, University of Eastern Finland. Language of the public defence is English.
For more information, please contact:
Timofei Eremin, timofei.eremin@uef.fi
