Synthesis, photophysical and photoelectrical properties of glass-forming phenothiazinyl- and carbazolyl-substituted ethylenes

Phenothiazinyl- and carbazolyl-substituted ethylenes have been synthesized and found to constitute electro-active materials with high thermal stability as characterised by thermo-gravimetric analysis. Steady state absorption and luminescence spectra of the synthesized derivatives were examined in detail revealing green-blue emission with efficiency ranging from 13 % to 28 %. Based on the emission spectra of the synthesized compounds Commission Internationale d’Eclairage (CIE) chromaticity coordinates have been obtained. Major luminescence decay time component of ~2.5 ns was determined in dilute solutions of the compounds, whereas significantly shorter one has been estimated in thin films. Electron photoemission spectra of the materials have been recorded and the ionisation potentials of 5.3-5.4 eV have been established. Room temperature hole drift mobilities of the diarylethylenes dispersed in polymeric host approached 10-5 cm2/Vs at high electric fields

New carbazole-indan-1,3-dione- based host materials for phosphorescent organic light emitting diodes

New carbazole- and indan-1,3-dione -based low molecular weight derivatives were synthesized and characterized by mass spectrometry and 1H NMR spectroscopy. Thermal behaviour of the derivatives was demonstrated by thermo-gravimetric analysis and differential scanning calorimetry. The materials were found to show very high thermal stability having initial thermal degradation temperatures in the range of 398- 401°C. Glass transition temperatures of the amorphous molecular materials were in the rage of 80–114°C. The derivatives were tested as host materials in blue phosphorescent organic light emitting diodes with iridium(III)[bis(4,6-difluorophenyl)- pyridinato-N,C2 ]picolinate as the guests. One of the blue OLED devices demonstrated rather low turn-on voltage of 5.0 V, a maximum luminance efficiency of 2.73 cd/A and maximum brightness of about 220 cd/m2Kauno technologijos universitetasVytauto Didžiojo universitetasŽemės ūkio akademij