Triplet-triplet annihilation upconversion materials as electrophoretic inks

Luminescent materials that can be reversibly switched by electric field stimulation are attractive since the potential application for optoelectronic devices. Here we report a triplet-triplet annihilation upconversion (TTA-UC) system with electrophoretic response which is developed as the electrophoretic ink. The TTAUC system consists of an ionic derivative of 9,10-diphenyl anthracene (DPA) as the annihilator and Pt(II) octaethylporphyrin (PtOEP) as the sensitizer. Upon applying an electric field, migration and enrichment of positively charged DPA derivatives towards the cathode results in a 20% enhancement of TTA-UC. A quasi -solid film for electrically writing is made using the electrophoretic TTA system as the ink and a platinum electrode as a pen. The prototype of TTA-UC ink demonstrates unique luminescence functions upon electrically writing and erasing, providing a promising strategy to develop electronic devices for display, information storage and encryption. (c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.