Chalcogen atom modulated persistent room-temperature phosphorescence through intramolecular electronic coupling

Abstract

A series of novel persistent room-temperature phosphorescence (pRTP) materials (PEPCz) obtained via a combination of chalcogen atoms (O, S, Se, and Te) and a carbazolyl moiety is reported. Single crystal structure analysis revealed that PEPCz had similar molecular conformations and almost identical crystal packing. Mechanistic study showed that the intramolecular electronic coupling between the chalcogen atoms and π-units was responsible for tunable pRTP. The PEPCz were used not only to realize graphic encryption, but also to fabricate pRTP sensors for H2O2 and TNT detection.

Crystal Engineering of Room Temperature Phosphorescence in Organic Solids

“…The pioneering Tang's work explicitly cites “carbonyl group, halogen atom and nonplanar conformation” as the key for the design of ORTP solids . Several other groups have found ORTP in the crystals of similar nonplanar molecules, although in most cases the overall emission is still dominated by fluorescence …”

Manipulating the Ultralong Organic Phosphorescence of Small Molecular Crystals

“…For molecule 43 , a large energy gap suppressed the ISC process, resulting in low phosphorescence quantum yield (Figure b). Benefiting from the highest efficiency for 42 , combined with its long lifetime, PSePCz was utilized in graphic encryption, and its aggregates were successfully used to fabricate sensors for H 2 O 2 and TNT (Figure c).…”

“…c) Photographs of pRTP before (left) and after (right) TNT or H 2 O 2 titration. Reproduced with permission . Copyright 2017, Royal Society of Chemistry.…”

Polymorphic Pure Organic Luminogens with Through‐Space Conjugation and Persistent Room‐Temperature Phosphorescence

“…In particular, those with persistent RTP (p-RTP) are also promising owing to the retaining of RTP emissione ven after ceasing the excitation sources, which means they can be used in encryption, oxygen and chemical sensing, and high-resolution molecular imaging with ideal signal-to-noise ratios. [17,[20][21][22][23][24][25][26][27][28][29][30][31] Meanwhile, whenc ompared to their inorganic or organometallic counterparts, pure organic RTP luminogens benefit from their good biocompatibility,a ppreciable processability,w ide variety,a nd so on. [17,[20][21][22]31] Despite dramatic advances having been achieved in the development of such p-RTP luminogens, [17,[20][21][22] solutions to some fundamental issues, such as au niversal molecular design strategy and the effective modulation of the photophysicalp rocesses and the emission mechanism, remaini n their infancy.T oa ddress these issues, it is of crucial importance to develop diverse p-RTP luminogens and to summarize their general underlying principles.…”

“…Recently, pure organic luminogens with room‐temperature phosphorescence (RTP) have attracted increasing attention owing to their fundamental importance in deciphering the photophysical processes of singlet and triplet excitons, as well as their potential applications in sensing, bioimaging, anticounterfeiting, and so forth. In particular, those with persistent RTP ( p ‐RTP) are also promising owing to the retaining of RTP emission even after ceasing the excitation sources, which means they can be used in encryption, oxygen and chemical sensing, and high‐resolution molecular imaging with ideal signal‐to‐noise ratios . Meanwhile, when compared to their inorganic or organometallic counterparts, pure organic RTP luminogens benefit from their good biocompatibility, appreciable processability, wide variety, and so on .…”