Author, Institution: Xiaofeng Tan, Kaunas University of Technology
Science area, field of science: Technological Sciences, Materials Engineering, T008
Dissertation was prepared externally.
Scientific Supervisor: Prof. Habil. Dr. Juozas Vidas Gražulevičius (Kaunas University of Technology, Technological Sciences, Materials Engineering, T008)
Dissertation Defence Board of Mechanical Engineering Science Field:
Prof. Dr. Jolita Ostrauskaitė (Kaunas University of Technology, Technological Sciences, Materials Engineering, T008) chairperson
Prof. Dr. Habil. Arvaidas Galdikas (Kaunas University of Technology, Technological Sciences, Materials Engineering, T008)
Prof. Dr. Habil. Saulius Grigalevičius (Kaunas University of Technology, Technological Sciences, Materials Engineering, T008)
Prof. Dr. Rasa Pauliukaitė (Center for Physical Sciences and Technology, Natural Sciences, Chemistry, N003)
Prof. Dr. Longin Lisetski (Institute for Scintillation Materials NASU, Ukraine, Technological Sciences, Materials Engineering, T008)
The doctoral dissertation is available on internet and at the library of Kaunas University of Technology (K. Donelaičio g. 20, Kaunas).
Doctoral dissertation was prepared at Kaunas University of Technology, Faculty of Chemical Technology, Department of Polymer Chemistry and Technology during the period of 2016-2020. The studies were supported by Horizon 2020 project “Excilight”. Dissertation was prepared externally.
The aim of this work is to design new types of electron-donating intermediates and electron-withdrawing intermediates, combine them into novel series of donor-acceptor type luminescence materials, and fabricate TADF-based OLEDs containing these materials.
The tasks set for the achievement of the above-stated aim are as follows:
- A series of molecules are designed and pre-screened through computational chemistry software. Then combined with computational chemistry data, assisted analysis of the performance of synthesized materials.
- Synthesis of new dibenzo oxa-hexcycline derivatives as the electron-donating intermediates, combining them into new series of donor-acceptor-donor type luminescent compounds. Characterization of the newly obtained materials.
- Synthesis and characterization of new star-shape luminescent materials with 1,3,5-triazine as the core, phenothiazine or phenoxy as peripheral units. Characterization of the newly obtained materials.
- Synthesis of new 1,2,4-triazine derivatives as electron-withdrawing intermediates, combining them into new series of donor-acceptor type luminescence compounds. Characterization of the newly obtained materials.
- Fabrication and characterization of OLEDs using newly synthesized materials
The novelty of the work:
- Novel structures. This thesis involves three series of organic compounds. Sixteen new organic light-emitting molecules were designed and synthesized, and their various properties were studied and discussed in detail. More importantly, at least six intermediates used in the synthesis of the target molecules are entirely new.
- Special Discovered the factors that affect triplet energy, thus providing a basis for the purposeful increase of triplet energy and the development of new blue light-emitting materials. It was also discovered that the star-shaped molecular structure has the potential for the dual luminescence mechanism of TADF and AIE, which provides possibilities for the development of efficient non-doped OLEDs. Finally, discovered the materials that can exhibit TADF in the dispersed state and RTP in the crystalline phase. Such discovery may allow developing the crystallization-induced room temperature phosphorescence technique.