Molecular-Level Imaging and Detection of Vibration of Fac-tris(2-phenylpyridine)iridium(III) Solids Through Transmission Electron Microscopy and Electron Energy Loss Spectroscopy

In organic solids, the heterogeneous distribution of organic molecules in the solid state gives rise to novel structure–property relationships. Here, we use transmission electron microscopy to investigate the aggregated structure of organic solid of a typical phosphorescent molecule Ir(ppy)3 at the atomic scale. Through the identification of heavy Ir atoms in the molecular structure, we reveal the existence of organic crystals, clusters and single molecules in the solids. Through electron energy loss spectroscopy, we explore the vibration modes of molecules and lattices in the solids and possible perturbations by excitons induced by electron beam, which could affect the electroluminescent property of the molecules.