“…In accordance to Jablonski diagram and emission mechanism of phosphorescence, two key factors should be taken into consideration to achieve highly efficient RTP emitter 14 : (i) strengthening the ISC from the excited singlet state (S m ) to the excited triplet state (T n ) via efficient spin-orbit coupling (SOC), and (ii) suppressing the nonradiative dissipation of the long-lived triplets caused by vibrational, molecular oxygen quenching or others. In this regard, molecular design strategies based on halogen bonding [15][16][17] , n-π transition via heteroatoms (S, P etc) [18][19][20] , and H-aggregation 21,22 , as well as RTP reinforcement approaches based on crystal engineering [23][24][25] , host-guest system [26][27][28] , copolymerization 29,30 and supramolecular interaction 31,32 , etc, have been developed and rendered the realization of pure organic RTP more effective.…”