| 초록 |
One of the current issues in realizing visible-to-UV and NIR-to-VIS triplet-triplet annihilated upconversion (TTA-UC) is limited energy match between sensitizer and acceptor, which is caused by large singlet-triplet energy splitting in intersystem crossing (ISC) of heavy-metal-based sensitizers. In this study, we report that an efficient visible-to-UV upconversion can be achieved even in oxygen-rich aqueous phase by utilizing oleic acid and new molecular pairs constituted by thermally activated delayed fluorescence (TADF) molecule as a sensitizer, having extremely small singlet-triplet energy splitting, and pyrene as an acceptor. The upconverted UV emission from the mixed solution containing 4CzIPN/pyrene pair shows a considerably increased intensity with laser irradiation time in comparison of its initial, which open the door to resolve the problems associated with photostability caused by the photobleaching and photodamage of converntional organic dyes. |
