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 TTA-UC 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.