Rigid ionic-bonding networks boosting organic room temperature phosphorescence

Ionic bonds possess excellent advantages in organic phosphorescence enhancement due to their intense electrostatic interactions, non-directional, and unsaturated characteristics. Nowadays, host-guest doping is the mainstream strategy for synthesizing room-temperature phosphorescent materials. While this strategy may suffer from compatible molecular configurations between host and guest, it needs precise molecular design and synthesis. Herein, ionic alkyl chain molecules are selected as hosts to prepare ionic phosphorescent materials handily. The host materials are suitable for diverse guests, simply attaching quaternary ammonium groups to chromophores. By altering the isolated chromophores, diverse phosphorescence colors from blue to orange-red can be emitted with long-lived lifetimes up to 572.27 ms. Consecutive ionic bonds can be formed in host-guest materials to construct ionic-bonding networks, thereby effectively restricting the movement of guest molecules and minimizing non-radiative transitions. Notably, the matching principle of the alkyl chain in the ionic host-guest system not only provides an ordered and rigid environment but also stimulates the external heavy-atom effect effectively, thus riveting chromophores for shining phosphorescence. This strategy, through the synergistic effects of host-guest doping and ionic-bonding networks, provides a reference for studying isolated-molecular phosphorescence with non-conjugated hosts.