Theoretical studies of organic molecules in OLEDs: From chemical stability to the excited-state nature

Since their first invention, the performance of organic light emitting diodes (OLEDs) have tremendously been improved for last three decades. In such a long journey, theoretical and computational studies have provided fundamental insights into various optical/physical /chemical phenomena in the devices and suggested the design rules of new efficient organic semiconducting materials to improve the device performance. Among many such studies, for example, in the case of thermally activated delayed fluorescence (TADF) phenomenon, which enables a full harvest of triplet excitons with organic emitters, our recent theoretical studies have unveiled the true nature of the singlet and triplet energy difference,1-2 and the role of different excited-nature between such states in the intersystem crossing.3 In addition, the role of multiple donor or acceptor units in enhancing the intersystem crossing rate and fluorescence rate was recently addressed.4 We recently also investigated the chemical stabilities of organic semiconducting materials in a combination of electron donor and acceptor units, pertaining to the device lifetime.5-6 In this talk, I would like to briefly discuss the chemical stabilities and excited-state natures of organic semiconducting materials in OLEDs.

References:

1. D. Kim, J. Phys. Chem. C 2015, 119, 12690.

2. K. Lee and D. Kim, J. Phys. Chem. C 2016, 120, 28330.

3. P.K. Samanta, D. Kim, V. Coropceanu and J.-L. Bredas, J. Am. Chem. Soc. 2017, 139, 4042.

4. C. Ahn and D. Kim, submitted.

5. H. Li et. al. Chem. Mater. 2019, 31, 1507

6. D. Kim, submitted.

20190502_대학원세미나_김동욱 교수.pdf