【Frontiers in HaiChuan Chemical Technology】Progress achieved in research on organic high-temperature residual polymer at East China University of Science and Technology

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Recently, the team led by Academician Tian He and Professor Ma Xiang from the School of Chemistry and Molecular Engineering at East China University of Science and Technology, as well as the Felinger Nobel Prize Scientist Joint Research Center, made an important breakthrough in the research of pure organic phosphorescent materials; the relevant findings were published in Nature Communications. Fig. a) Schematic diagram of the coupling strategy between hydrogen bond anchoring and single-bond rotor structure ； b) Jablonski diagram of the dynamic high-temperature afterglow phenomenon and c) actual photographs ； d) Current research progress on high-temperature resistant flexible phosphorescent polymer materials. Organic phosphorescent materials have great potential for applications in anti-counterfeiting and sensing due to properties such as long lifetime and large Stokes shift, but their luminescence is easily quenched by molecular thermal vibrations at high temperatures. Previous studies have primarily focused on room-temperature environments, which limits their application scenarios. The Ma Xiang team adopted a host-guest anchoring strategy: using hydrogen-bond-rich polyacrylamide as the matrix and a triphenylamine derivative containing a single-bond rotor (TPCS-4) as the luminescent unit, they successfully developed a programmable high-temperature afterglow polymer. Thanks to the strong suppression of molecular thermal motion by the hydrogen bond network, this material exhibits a phosphorescent emission lifetime of up to 836 ms at room temperature, with a luminous quantum yield as high as 61.7%; it can also maintain a afterglow lasting up to 5 seconds at a high temperature of 423 K. Further studies have shown that the single-bond rotor in TPCS-4 can undergo rotation at high temperatures, thereby driving a conformational change of the triplet excited state (T1), ultimately resulting in a blue shift of the phosphorescence wavelength. This study overcomes the previous limitations imposed by the Kasha rule on the emission wavelength, enabling dynamic afterglow with high-temperature tolerance and wavelength tunability (from 508 nm to 450 nm) under the condition of a single chromophore, thereby expanding the usage conditions and application scenarios for pure organic phosphorescent materials.