Recent Theoretical Advances in Understanding the Mechanism of Aggregation-Induced Emission for Small Organic Molecules

Characterization and Photophysical Properties of a Luminescent Aluminum Hydride Complex Supported by a β-Diketiminate Ligand

“…Hence, relatively large HR factors (>10) have appeared in some well-known AIE-active molecules within the range of 10 to 100 cm −1 . These low-energy modes are generally attributed to rotational vibration or out-of-plane vibration of a π-system, like peripheral phenyl groups, in the molecules [53][54][55][56][57]. On the other hand, such low-frequency modes with large HR factors are absent or few for typical AIE-inactive molecules, while these molecules possess smaller (<1) HR factors in the high-frequency region (-1500 cm −1 ).…”

“…On the other hand, such low-frequency modes with large HR factors are absent or few for typical AIE-inactive molecules, while these molecules possess smaller (<1) HR factors in the high-frequency region (-1500 cm −1 ). The corresponding high-energy normal modes are generally assigned to single-or double-bond stretching modes of the π-conjugated systems [53][54][55][56][57].…”

“…It should be noted that we still neglect the breakdown of the adiabatic approximation in this regime. To treat the real systems in more accurate manner, we should need further considerations, for example Duschinsky rotation [55][56][57].…”

Structural Landscape of Zn(II) and Cd(II) Coordination Compounds with Two Isomeric Triimidazole Luminophores: Impact of Crystal Packing Patterns on Emission Properties

“…Organic light-emitting diodes (OLEDs) are promising devices for this task, since they consume only a fraction of the energy of conventional, inefficient light bulbs and can be manufactured on thin, flexible, and lightweight substrates. The concept of aggregation induced emission (AIE) pioneered by Tang et al in 2001 nowadays is intensively studied for the above-mentioned applications. − Most of the AIE materials exhibit high fluorescence quantum yields (QY) in the solid state or in colloidal aggregates but weak fluorescence in dilute solutions. Among the factors responsible for the AIE phenomenon, the restriction of intramolecular rotation (RIR) and/or intramolecular motion (RIM), heavy-atom (halogen) effect, impact of hydrogen bonding, and favorable arrangement of luminophores in the crystal lattice − should be mentioned, all leading to a suppression of radiationless deactivation pathways.…”

“…The widespread research for a better understanding of the factors essential to optimizing emission properties in the solid state revealed that packing features are among the most important in affecting the bright fluorescence and room temperature phosphorescence (RTP). − In order to obtain ultralong phosphorescence (RTUP), a stable long-lived excited triplet state (T 1 ) is a necessary condition. It has been proven that the packing mode with strong π–π interactions is one of the most effective features in stabilizing the T 1 state, resulting in persistent RTP. ,, …”