The penetration of water molecules not only loosened the aggregates to reduce the RIM effect, but also provided a more polar environment for TPA-BBT, which should cause a severe TICT effect to reduce the fluorescence intensity. The atomic contact ratios of the innermost TPE-BBT and TPA-BBT were also calculated (Figure ). TPE-BBT showed a higher contact ratio, which meant that a higher ratio of atoms in TPE-BBT interacted with surrounding organic molecules and the atomic fluctuations could be restricted. This result indicated a higher degree of RIM for TPE-BBT aggregates in water. Finally, to quantitatively evaluate the intermolecular interactions, the interaction energy (composed of electrostatic energy and van der Waals energy) of the innermost molecule with surrounding organic molecules was calculated (Figures and). The innermost TPE-BBT had much higher interaction energy than TPA-BBT, further proving the higher extent of RIM for TPE-BBT aggregates in water. The total interaction energy (composed of electrostatic energy and van der Waals energy) of the innermost molecules in TPE-BBT and TPA-BBT aggregates at different times.