Design, Synthesis, Fundamental Understanding, and Advanced Applications of Molecular Aggregates

Compared with single molecule, molecular aggregates usually show distinctly different behaviors and properties. For example, most of the traditional dyes are highly emissive in dilute solutions at single molecular level but show quenched emission at the aggregate states. However, some luminogens are weakly or non-emissive as free molecules but become highly emissive due to the formation of molecular aggregates. The latter luminogens show attractive aggregation-induced emission (AIE) behavior and are called AIEgens. The molecular aggregates are high dependent on the chemical structure of a single molecule. Many intermolecular interactions should be taken into account in molecular aggregates, including non-covalent bonding, host–guest interactions, electron/energy transfer processes, steric hindrance effects, etc. Understanding the complex intermolecular interaction in molecular aggregate systems is of great fundamental importance and has far-reaching practical implications.

Aggregate science has attracted considerable attention of researchers in various fields, including aggregation-induced emission (AIE), aggregation-induce delayed fluorescence (AIDF), room temperature phosphorescence (RTP), clusteroluminescence, circularly polarized luminescence (CPL), etc. The establishment of new fundamental principles and working mechanisms will enable rational design of novel aggregate systems and judicious development of functional materials, which show attractive applications in organic light emitting diodes (OLEDs), anti-counterfeit materials, stimuli-responsive materials, chemo-sensing, multimodality bio-imaging and theranostics. Although plenty of exciting works have been achieved, there are still many challenges and opportunities left for further exploration in the molecular aggregate science. The comprehensive investigation of aggregate science will generate new hypotheses, theories and knowledge for us to better understanding the natural laws, which will help fill the gaps between the macro- and micro-worlds.

This Research Topic will collect the recent progresses of design and synthesis, fundamental understanding, and advanced applications of molecular aggregates. Perspectives, Reviews, Mini Reviews and Original research articles will be welcomed. Areas to be covered in this collection may include, but are not limited to:
• Design and development of new AIE systems
• Theoretical investigations of new AIE mechanisms and through-space interactions
• Novel molecular aggregate systems for chemosensing, bioimaging and theranostics
• Advances in aggregation-induced delay fluorescence
• Studies on clusterization-triggered emission
• Mechanistic study and advances in Mechanoluminescence
• Aggregate enhanced chirality and luminescence