Singular photoluminescence behavior of Alq3 films at very long decay time

Optical photoluminescence of thermally evaporated Alq3 thin films has been studied for over six years in a few samples annealed and non-annealed and afterwards exposed to the laboratory atmosphere. It was found that the measured emission intensity decays with four different time-spectral behaviors, which imply the existence of four molecular aggregations, or components. Insights have unveiled their interactions with environment agents, which are useful both for optoelectronic utilizations of this ubiquitous organo-metallic molecule possessing a long emission lifetime and for basic research and application of similar organic molecules.