| Abstract [eng] |
Many years have passed since the first organic light emitting diode was developed, during which time this field of technology has improved significantly. Simple single-layer structures have been replaced by complex multi-layer, tandem, or inverted organic light emitting diode structures, that have been more efficient, and now new organic materials are being sought that could potentially be used in diodes and further increase their efficiency. One of the potential organic materials that could be used in the production of organic light emitting diodes is diphenylamine substituted quinazoline derivatives to create a donor-acceptor system that is characteristic of thermally activated delayed fluorescence materials. In this work, a one-step synthesis of diphenylamine-substituted quinazoline derivatives have been performed and their photophysical and electrochemical properties have been investigated. The disubstituted quinazoline derivatives did not show solvatochromism in solutions of different polarity, and the mono-substituted quinazoline derivatives showed the solvatochromism with emission ranging from blue to orange. 4-Methoxy-N-(4-methoxyphenyl)-N-[4-(4-phenylquinazolin-2-yl) phenyl]aniline has the most efficient green emission (84% of solution, 26% of layer). Diphenylamine-substituted quinazoline derivatives absorb UV/VIS light up to 406 nm. Examination of the photophysical properties of monosubstituted quinazoline derivatives layers showed that the compounds exhibited thermally activated delayed fluorescence. Cyclic voltammetry showed that mono- and di-substituted quinazoline derivatives are characterized by reversible oxidation and reduction. The results also show that monosubstituted quinazoline derivatives have lower ionization energy, with 4-methoxy-N-(4-methoxyphenyl)-N- [4-(4-phenylquinazolin-2-yl)phenyl]aniline has the lowest ionization energy of 5.39 eV. Using photoemission in air method was found that, the lowest ionization energy has 4-(methylthio)-N- [4-(methylthio) phenyl]-N-[4-(4-phenylquinazolin-2-yl) phenyl]aniline, which was 5.31 eV. |
