From Cascade Photoresponsive Capsules to Orange-Emitting TADF Chiral dimers

Marine Louis¹, Magin Ferrer², Harada Daiyu¹, Kanno Natsuko³, Yugo Tsuji¹, Chigusa Goto¹, Yasuhara Kazuma¹, Clemence Allain², Remi Metivier², Shizu Katsuyuki³, Keitaro Nakatani², Hironori Kaji³, Tsuyoshi Kawai¹.

1. Photonic and Reactive Molecular Science Laboratory Nara Institute of Science and Technology, Nara, Japan. 2. ENS Paris-Saclay, Laboratoire de Photophysique et Photochimie Supramoleculaire et Macromoleculaire, Gif-sur-Yvette, France. 3. Kyoto University, Kaji Laboratory, Kyoto, Japan.

This talk will be divided in two parts that represents the two main topics of my research activities in NAIST.

The first part will focus on the development on photoresponsive capsules. Previous studies of our laboratory have reported that some terarylene photochromes exhibit highly efficient, non-linear, ring-opening reactions induced by halogen radicals with more than 1000 molecules converted per trigger, which include UV or X-ray exposure. Therefore, it is expected to be applied as sensors.¹ However, so far the detection purely relies on a color change with low contrast and only works in solution. This project aims at encapsulated these systems in micro-sized capsules to make them safer and easier to handle while incorporating a fluorophore to increase the contrast and detection sensitivity.

The second part will focus on my focus to couple thermally activated delayed fluorescence (TADF) properties with circularly polarized luminescence (CPL). Both have shown, among others, strongly promising application potential in the development of organic light emitting diods. This works aims at unraveling the effect of dimerization on TADF properties from non-TADF monomers. The dimeric system being chiral their CPL properties were also studied. By combining experimental and theoretical approaches (TDDFT and CIS) the effects of the conjugation extension and intramolecular Davydov Splitting were discussed in the apparition of TADF properties after dimerization.

Figure 1: A. Images of photoresponsive capsules. B. Structure of studied monomer and dimers synthesized with TADF activation via dimerization due to Davydov Splitting.