In recent years, organic afterglow systems with long lifetimes and high efficiency have been achieved through promoting the intersystem crossing (ISC) process and suppressing the nonradiative decay using crystallization/H-aggregation, supramolecular self-assembly and other strategy. [2] However, vast majority of the reported materials usually display the afterglow emission bands ranging from 500 to 600 nm owing to low-lying exciton energies of their triplet state and the unavoidable bathochromic shifts compared to the single-molecular fluorescence via aggregation coupling and intermolecular electronic interaction. [3] Nevertheless, the realization of the blue/deep-blue organic afterglow with high quantum efficiency and long lifetime remains a big challenge because of the difficulty of stabilizing and populating the high-lying triplet excited state simultaneously, [4] although they constitute the essential core element for the applications in solid-state lighting and full-color display. [4b] Host-guest doping strategy is believed to be an efficient way for developing blue afterglow on account of their outstanding ability of inhibiting the bathochromic shift at low doping concentrations through the obstruction of molecular aggregation and electronic coupling. [4b,5] Unfortunately, the afterglow materials constructed via the host-guest doping strategy generally suffer from the low luminous efficiency due to the low doping concentration of the guest molecules and low compatibility between polar host and guest molecules. [6] Recently, to overcome these intrinsic difficulties, Huang and his co-workers proposed an efficient method to achieve deep-blue organic afterglow (406-428 nm) with long lifetime of 1.67 s and quantum yields of 46.1% through sensitizing the triplet exciton of guest (Trimesic acid) by host molecules (cyanuric acid) and water implement to suppress the nonradiative decays for matrices rigidification. [4b] Subsequently, Chen et al. developed stable deep-blue ultralong room temperature phosphorescence materials with ultralong lifetime of 5.08 s and of high quantum efficiency of 37.6% via simply doping boron phosphor into cyanuric acid host to establish abundant H-bonds. [7] Despite the recent efforts, it remains difficult to achieve efficient blue/deep-blue organic afterglow with high quantum efficiency. Therefore, novel afterglow materials with Blue/deep-blue emission is an essential core element for application in organic optoelectronics, but it remains an enormous challenge in organic afterglow owing to the difficulties in the stabilization of the high-lying triplet excited state. Here, an effective approach to develop a deep-blue delayed fluorescence (DF) supramolecular assembly with long lifetime and recordhigh quantum efficiency up to 0.62 s and 81%, respectively, is proposed via the increase in the delocalization degree of guest molecules induced by the co-assembly of guest molecules with Laponite (Lap) achieved via simple solvent-free grinding approach. Thereby the excitation energy of si...
