The phenomenon in which organic luminophores show higher photoluminescence efficiency in the aggregated state than in solution is called aggregation-induced emission enhancement (AIEE). Some luminophores, e.g., diketopyrrolopyrrole-based and sulfonamide-based luminophores, only display enhanced emission upon entering the crystalline state. That is, these luminophores are said to exhibit crystallization-induced emission enhancement (CIEE).
Luminophores such as noble metallic nanoclusters show higher
photoluminescence efficiency in the aggregated state than homogenous
dispersion in solution. This phenomenon is known as
Aggregation-Induced Emission (AIE).