Color‐Tunable Room Temperature Afterglow of Non‐Conventional Organogels for Dynamic Anti‐Counterfeiting

Abstract

AbstractLow‐molecular‐weight organogels with ultra‐long room temperature phosphorescent (RTP) are ideal materials for dynamic anti‐counterfeiting, due to their sensitive thermal‐responsive character. However, it is a great challenge to realize ultra‐long RTP in a single‐component organogel because conventional auxiliary groups for the promotion of gel formation are usually flexible, which increases non‐radiative decay through molecular motions to quench the RTP. Non‐conventional organogelators with rigid chemical structures may be able to alleviate the non‐radiative decay to maintain the phosphorescent characters in the gel state like in the crystalline state. In this work, potential low‐molecular weight phosphorescent organogelators with rigid chemical structures are predicted by using the descriptors derived from all‐atom molecular dynamics simulation, and successfully screen out two RTP non‐conventional organogelators. It is exciting that one of them exhibited ultra‐long RTP in the gel state. Furthermore, triplet‐to‐singlet Forster resonance energy transfer between the RTP gelator (donor) and fluorescent sulforhodamine 101 (SR101) (acceptor) in the gel state provided a long‐lived red fluorescence. Due to the sensitive thermal‐responsive property of organogel, the afterglow can be well switched between “on” and “off” with excellent fatigue‐resistant properties, which is promising for dynamic anti‐counterfeiting.