4:30 PM - 5:00 PM
[20p-W631-7] Theoretical and Computational Chemistry for Organic Device Materials
Keywords:organic light-emitting diode,thermally activated delayed fluorescence,theoretical chemistry
Organic light-emitting diodes (OLEDs) are now commercially available in mobile phones and TVs and have attracted great attention because of their potential application for flexible flat-panel displays and next-generation solid-state lighting sources. In an OLED, because singlet and triplet excitons are generated in the ratio of 1:3, the electroluminescence efficiency of OLEDs depends largely on the efficiency of converting the triplet excitons into light.
Thermally activated delayed fluorescence (TADF) emitters can exhibit high triplet-to-light conversion efficiency and therefore, are promising as emitting dopants for OLEDs.We have developed a theoretical method that makes possible an intuitive understanding of origins of radiative and non-radiative decays in TADF emitters. In this study, using the theoretical method, we derived a guideline for improving the luminescence efficiency of TADF emitters by suppressing non-radiative decays and promoting radiative decays. We developed highly efficient green and blue TADF emitters. OLEDs containing these TADF emitters as emitting dopants exhibited external quantum efficiencies much higher than those obtained with conventional fluorescent emitters.
We also performed charge transport simulations in organic amorphous materials using quantum chemical calculations and Monte Carlo simulations. We found that unlike in crystalline materials, molecular pairs with a large electronic coupling do not necessarily contribute to the charge transport in amorphous materials. As an example, we report here theoretical analyses for a thin film of N,N'-dicarbazole-3,5-benzene, a widely used host material for OLEDs.
Thermally activated delayed fluorescence (TADF) emitters can exhibit high triplet-to-light conversion efficiency and therefore, are promising as emitting dopants for OLEDs.We have developed a theoretical method that makes possible an intuitive understanding of origins of radiative and non-radiative decays in TADF emitters. In this study, using the theoretical method, we derived a guideline for improving the luminescence efficiency of TADF emitters by suppressing non-radiative decays and promoting radiative decays. We developed highly efficient green and blue TADF emitters. OLEDs containing these TADF emitters as emitting dopants exhibited external quantum efficiencies much higher than those obtained with conventional fluorescent emitters.
We also performed charge transport simulations in organic amorphous materials using quantum chemical calculations and Monte Carlo simulations. We found that unlike in crystalline materials, molecular pairs with a large electronic coupling do not necessarily contribute to the charge transport in amorphous materials. As an example, we report here theoretical analyses for a thin film of N,N'-dicarbazole-3,5-benzene, a widely used host material for OLEDs.