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Herein, we realized the quick generation of stable photoinduced radicals in donor–acceptor triarylphosphines with associated color changes of emission and absorption, which was deciphered by the electron paramagnetic resonance (EPR) spectra.

An antibody–AIEgen conjugate is designed and developed as a “turn-on” fluorescent probe for wash-free specific cancer cell imaging. The cetuximab-conjugated AIEgen shows red fluorescence only when it is internalized and accumulated in cancer cells with overexpressed epidermal growth factor receptor through endocytosis. The probe first lights up the lysosomes. After hydrolysis, its residue is accumulated in mitochondria, making them highly emissive with a long cell retention time. Compared with conventional “always-on” fluorescent probes, the antibody–AIEgen conjugate exhibits a very good image contrast during wash-free cancer cell imaging and less interference from normal cells. To the best of our knowledge, this is the first time “turn-on” antibody–AIEgen conjugates have been reported. This new strategy can be further extended to many proteins and water-soluble AIEgens, and many of their potential applications such as real-time tracking of cell dynamics and cancer theranostics will be explored. The present work is expected to inspire more marvellous research in the fields of AIE and cancer imaging.

Solid-state photochromism was found in bis(diphenylmethylene)dihydrotetracene, caused by photocyclization of the embedded cis-stilbene motifs., Reported herein is a new class of pure polycyclic hydrocarbon molecules, designed through a novel aggregation-induced emission (AIE) strategy, with unexpected photochromic properties. The restriction of intramolecular motion was found as a comprehensive mechanism for the AIE effect. The photochromism mechanism study revealed that the photocyclization reaction of cis-stilbene, the molecular conformation in the single crystal and the tetracene backbone should contribute to the unique photo behavior. In particular, the fast responsive, photo-reversible and thermo-irreversible photochromic effect facilitated in the solid state opens a new field of aggregation-promoted photochromism.

A novel dark through-bond energy transfer (DTBET) strategy is proposed and applied as the design strategy to develop ratiometric Hg2+ sensors with high performance., A novel dark through-bond energy transfer (DTBET) strategy is proposed and applied as the design strategy to develop ratiometric Hg2+ sensors with high performance. Tetraphenylethene (TPE) derivatives with aggregation-induced emission (AIE) characteristics are selected as dark donors to eliminate emission leakage from the donors. The TBET mechanism has been adopted since it experiences less influence from spectral overlapping than Förster resonance energy transfer (FRET), making it more flexible for developing cassettes with large pseudo-Stokes shifts. In this work, energy transfer from the TPE derivatives (dark donor) to a rhodamine moiety (acceptor) was illustrated through photophysical spectroscopic studies and the energy transfer efficiency (ETE) was found to be up to 99%. In the solution state, no emission from the donors was observed and large pseudo-Stokes shifts were achieved (>280 nm), which are beneficial for biological imaging. Theoretical calculations were performed to gain a deeper mechanistic insight into the DTBET process and the structure–property relationship of the DTBET cassettes. Ratiometric Hg2+ sensors were rationally constructed based on the DTBET mechanism by taking advantage of the intense emission of TPE aggregates. The Hg2+ sensors exhibited well resolved emission peaks. >6000-fold ratiometric fluorescent enhancement is also achieved and the detection limit was found to be as low as 0.3 ppb. This newly proposed DTBET mechanism could be used to develop novel ratiometric sensors for various analytes and AIEgens with DTBET characteristics will have great potential in various areas including light harvesting materials, environmental science, chemical sensing, biological imaging and diagnostics.

Conjugated macrocycles can be equipped with interesting functions by having polycyclic aromatic hydrocarbon (PAH) building blocks that are larger than benzene. The building block explored herein is phenanthrene, which is connected with varied linkers leading to new trimeric conjugated macrocycles (1–4). The coronal macrocycle 1, whose π-backbone is a new segment of [6,6]-carbon nanotube, is synthesized from the flat macrocycle 2 by Lewis acid-catalyzed [4 + 2] benzannulation. This suggests a new strategy to synthesize π-extended nanorings from conjugated macrocycles that are more easily accessed. As found from a comparative study with focus on self-assembly and organic semiconductor behavior, flat or nearly flat conjugated macrocycles 2–4 function as p-type organic semiconductors in solution-processed thin film transistors. Their field effect mobility as measured from as-cast films is dependent on their ability of self-aggregation in solution.