Abstract
Advanced 1.5-µm emitting materials that can be used to fabricate electrically driven light-emitting devices have the potential for developing cost-effective light sources for integrated silicon photonics. Sensitized erbium (Er(3+)) in organic materials can give bright 1.5-µm luminescence and provide a route for realizing 1.5-µm organic light emitting diodes (OLEDs). However, the Er(3+) electroluminescence (EL) intensity needs to be further improved for device applications. Herein, an efficient 1.5-µm OLED made from a sensitized organic Er(3+) co-doped system is realized, where a "traditional" organic phosphorescent molecule with minimal triplet-triplet annihilation is used as a chromophore sensitizer. The chromophore provides efficient sensitization to a co-doped organic Er(3+) complex with a perfluorinated-ligand shell. The large volume can protect the Er(3+) 1.5-µm luminescence from vibrational quenching. The average lifetime of the sensitized Er(3+) 1.5-µm luminescence reaches ~0.86 ms, with a lifetime component of 2.65 ms, which is by far the longest Er(3+) lifetime in a hydrogen-abundant organic environment and can even compete with that obtained in the fully fluorinated organic Er(3+) system. The optimal sensitization enhances the Er(3+) luminescence by a factor of 1600 even with a high concentration of the phosphorescent molecule, and bright 1.5-µm OLEDs are obtained.