Long‐Range Charge Transportation Induced Organic Host–Guest Dual Color Long Persistent Luminescence

Abstract

Long persistent luminescence (LPL) can store light energy in excited states and gradually release it as light. Organic host–guest systems provide a good platform for LPL, and single‐color LPL is often achieved while multicolor LPL is challengeable. Here host–guest supramolecular complexes are presented with dual LPL emissions: thermally activated delayed fluorescence (TADF) (≥100 ms) and room temperature phosphorescence (RTP). A space charge transfer from α‐cyclodextrin to diphenylacetylene (DPA) with long‐range transportation (2.32 mm) carrier along DPA strand in the supramolecular complexes is attributed to generate the TADF and RTP. Fortunately, these supramolecular complexes are readily fabricated from α‐cyclodextrin and DPA or DPA derivatives. The gradient color is observed after removing UV excitation. Furthermore, the hydrophobic property inside α‐cyclodextrin makes the LPL appear by water shedding and disappear by organic solvent infiltration, showing the character of a “switch.” This host–guest space charge transfer strategy paves a way to design LPL materials.

Room-Temperature Phosphorescence of Pure Axially Chiral Bicarbazoles

“…This has led us to ask whether it is possible to achieve RTP from pure Cz. We had to set our sights on ( R/S )-octahydro-binaphthyl-based bicarbazoles ( BiCz ) (Figure b), because (1) in the isolated state, axial chirality with a twisted helical structure would help not only to acquire circularly polarized luminescence (CPL) but also to break molecular symmetry and π-conjugation to facilitate intramolecular CT from one Cz unit to the other Cz unit and reverse ISC (RISC) for TADF; , (2) in the aggregated state, intermolecular interactions would lead to long-range intermolecular CT as an excellent scaffold for RTP; , (3) the greater steric hindrance of 16 peripheral H atoms in cyclohexane parts could suppress the accumulation of molecules to slow exciton annihilation and singlet–triplet energy splitting (Δ E ST ); and (4) n−π* aromatic ketone moieties would reduce the El-Sayed rule for RTP. − , …”

Efficient and Color‐Tunable Dual‐Mode Afterglow from Large‐Area and Flexible Polymer‐Based Transparent Films for Anti‐Counterfeiting and Information Encryption

“…So, both IaCzA‐0.1 %‐PVA and IbCzA‐0.1 %‐PVA films can produce dual‐mode afterglow that is composed of pTADF and ultralong phosphorescence at room temperature, which is seldom reported for polymer‐based luminescent materials. The satisfactory Φ afterglow value (19.8 %) combined with the ultralong lifetimes (1.81 s for the pTADF and 1.76 s for the UOP) thus demonstrates that the IbCzA‐0.1 %‐PVA film presents state‐of‐the‐art dual‐mode organic afterglow performance (Figure S1 and Table S1) [1f, 5b, 8b,c, 13b–e, 14] . When the doping concentration of IbCzA was changed to 0.5 %, higher PLQY (71.7 %) and Φ afterglow (21.3 %) values could be achieved from the resulting polymer film, but the lifetimes of the pTADF and UOP were slightly reduced to 1.52 and 1.38 s (Figure S19), respectively.…”

Near-Infrared Emission Material with Superlong Afterglow Performance and Its Multifunctional Applications

“…This intrinsic characteristic can eliminate the in situ background noise brought by the excitation light source. Therefore, it is theoretically possible to obtain signals with an ultrahigh signal-to-noise ratio, so it has gradually attracted widespread attention in many fields such as biological imaging, biological sensing, information anticounterfeiting, information storage, and other non-invasive detection. − …”