Abstract
Room-temperature phosphorescence (RTP) of purely organic materials is
easily quenched with unexpected purposes because the excited triplet
state is extremely susceptible to external stimuli. How to stabilize the
RTP property of purely organic luminogens is still challenging and
considered as the bottleneck in the further advancement of the bottom-up
approach. Here, we describe a gated strategy that can effectively
harness RTP by employing complexation/dissociation with proton. Due to
the order-disorder transition orientation of intermolecular packing, the
RTP of triazine derivative Br-TRZ will easily vanish upon mechanical
force. Impressively, by enhancing its intramolecular charge transfer
effect, the protonated Br-TRZ stubbornly possesses an obvious RTP under
external grinding, whatever in the ordered or disordered intermolecular
arrangement state. Consequently, the “Lock” gate of RTP was achieved
in the protonated Br-TRZ molecule. Combined with theoretical calculation
analysis, the enhanced charge transfer effect can narrow the
singlet−triplet energy gap significantly, and stabilize the RTP property
of triazine derivative sequentially. Furthermore, the locked RTP can be
tuned via proton and counterions repeatedly and show excellent
reversibility. This gated RTP concept provide an effective strategy for
stabilizing the RTP emission of purely organic systems.