Time‐Dependent Afterglow of Non‐Conventional Organogel for Multi‐Level Dynamic Anti‐Counterfeiting

Abstract The ultra‐long room temperature phosphorescent (ULRTP) organogels with multiple signal outputs are rare, despite of their promising applications in sensing and security due to their exceptional sensitivity to analytes and external stimuli. In this study, three methoxy groups are introduced into a previously reported carbazole‐based ULRTP organogelator. It is discovered that the methoxy units enhance intermolecular interactions, which facilitates gelation. Additionally, the new gel demonstrated ULRTP with time‐dependent afterglow and temperature‐sensitive phosphorescent properties. A detailed investigation reveals that trace impurity from commercial carbazole is responsible for the ULRTP and time‐dependent phosphorescence. The temperature‐sensitive ULRTP and time‐dependent afterglow properties of the gel make it a promising candidate for multi‐level security applications.