T. Matulaitis “Studies of synthesis and properties of bipolar compounds for organic optoelectronic devices” doctoral thesis defence

Author, Institution: Tomas Matulaitis, Kaunas University of Technology,

Science area, field of science: Technological Sciences, Materials Engineering – 08T

Summary of doctoral thesis: Summary

Scientific Supervisor: Prof. habil. dr. Juozas Vidas Gražulevičius (Kaunas University of Technology, Technological sciences, Materials engineering 08T).

Dissertation Defence Board of Materials Engineering Science Field:
Prof. Dr. Habil. Sigitas Tamulevičius (Kaunas University of Technology, Technological sciences, Materials engineering 08T) – chairman,
Prof. Dr. Saulius Grigalevičius (Kaunas University of Technology, Technological sciences, Materials engineering 08T),
Prof. Dr. Habil. Vidmantas Gulbinas (Cetre for Physical Sciences and Technology, Physical Sciences, Physics – 02P),
Assoc. Prof. Dr. Jolita Ostrauskaitė (Kaunas University of Technology, Technological sciences, Materials engineering 08T),
Prof. Dr. Peter Strohriegl (Bayreuth University, Physical Sciences, Chemistry – 03P).

The doctoral dissertation is available on the internet and at the library of Kaunas University of Technology (K. Donelaičio str. 20, Kaunas).

Annotation:

The aim of this work is the development of new bipolar materials and a comparative study of their properties regarding their use in organic optoelectronic devices. In order to achieve the aim of the thesis, the following objectives were outlined:

• Synthesis, characterization and study of the properties and applicability in OLEDs of new star-shaped triazine derivatives.
• Synthesis of a new meta-conjugated derivative of 1,3,5-triazine and carbazole and investigation of its thermally activated delayed fluorescence (TADF) properties.
• Synthesis, characterization and investigation of the structure-property relationship of new carbazole and benzonitrile derivatives.
• Synthesis and comparative study of the properties of new isomeric derivatives of 9,9-dimethyl-9,10-dihydroacridine and benzonitrile.
• Synthesis, characterization and investigation of photovoltaic properties of a new derivative of benzothiadiazole having both donor and acceptor substituents.

Four new bipolar star-shaped derivatives of carbazole and 2,4,6-triphenyl-1,3,5-triazine were designed, synthesized and characterized. The compounds are applicable as emitters in OLEDs. Three new blue-emitting isomeric derivatives of 9,9-dimethyl-9,10-dihydroacridine and benzonitrile were prepared and characterized. It was discovered that ortho-linkage is responsible for the high-lying triplet state, as well as for the least polarity sensitive ¹CT state among the isomers resulting in the most efficient TADF.