Host Surface-Induced Excitation Wavelength-Dependent Organic Afterglow

The design and construction of organic afterglow materialsis anattractive but formidably challenging task due to the low intersystemcrossing efficiency and nonradiative decay. Here, we developed a hostsurface-induced strategy to achieve excitation wavelength-dependent(Ex-De) afterglow emission through a facile dropping process. Theprepared PCz@dimethyl terephthalate (DTT)@paper system exhibits aroom-temperature phosphorescence afterglow, with the lifetime up to1077.1 +/- 15 ms and duration time exceeding 6 s under ambientconditions. Furthermore, we can switch the afterglow emission on andoff by adjusting the excitation wavelength below or above 300 nm,showing a remarkable Ex-De behavior. Spectral analysis demonstratedthat the afterglow originates from the phosphorescence of PCz@DTTassemblies. The stepwise preparation process and detailed experiments(XRD, H-1 NMR, and FT-IR analysis) proved the presence ofstrong intermolecular interactions between the carbonyl groups onthe surface of DTT and the entire frame of PCz, which can inhibitthe nonradiative processes of PCz to achieve afterglow emission. Theoreticalcalculations further manifested that DTT geometry alteration underdifferent excitation beams is the main reason for the Ex-De afterglow.This work discloses an effective strategy for constructing smart Ex-Deafterglow systems that can be fully exploited in a range of fields.

Automated summary

In this study, we developed a surface-induced strategy to achieve excitation wavelength-dependent afterglow emission. The prepared PCz@DTT@paper system exhibited room-temperature phosphorescence afterglow with a lifetime of 1077.1 +/- 15 ms and a duration time of over 6 s. By adjusting the excitation wavelength, the afterglow emission could be switched on and off, showing remarkable excitation wavelength-dependent behavior. This work provides an effective strategy for constructing smart afterglow systems that can be fully utilized in various fields.