Novel naphthalimide derivatives (NIM) with donor-acceptor architecture were successfully constructed and their unique fluorescent properties were investigated. In particular, the fluorescence intensities of 4-methoxystyrene substituted NIM-1 were solvent independent and its quantum yields varied from 0.4 in toluene to 0.52 in MeOH. However, 4-(N,N-diphenylamino) styrene substituted NIM-2 and 4-nitrostyrene substituted NIM-3 exhibited low luminescence in dilute solutions but were efficiently fluorescent under conditions of molecular aggregation. NIM-2 showed strong solid fluorescence with a longer wavelength emission and larger Stokes shift. In addition, NIM-3 showed unexpected blue-green fluorescence due to the formation of fluorescent organic nanoparticles (FONs) under mixed solution. These two cases were ascribed to the aggregation-induced enhanced emission (AIEE) effects and which can also reasonably explain the bright cellular images observed when cells were incubated with NIM-2 and NIM-3. Furthermore, compound NIM-2 can be used to recognize cancer cells owing to its subcellular behaviour

Co-adsorption of N719 dye and an H-NIM fluorophore results in an in situ FRET effect and improves the photovoltaic performance of DSSCs.

A water-soluble pH sensor, 2-(6-(4-aminostyryl)-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)-N, N-dimethylethanamine (ADA), was synthesized based on the molecular design of photoinduced electron transfer (PET) and intramolecular charge transfer (ICT). The fluorescence emission response against a pH value is in the range 3-6, which is suitable for labelling intracellular pH-dependent microenvironments. After biological evolution, ADA is more than a pH biosensor because it is also an endocytosis pathway tracking biosensor that labels endosomes, late endosomes, and lysosome pH gradients. From this, the emissive aggregates of ADA and protonated-ADA in these organs were evaluated to explore how this probe stresses emission colour change to cause these unique cellular images.

An organic fluorophore is doped into a mesoporous TiO2 photoelectrode to absorb ultraviolet light and convert it to green light for more efficient light harvesting of N719 dye. This fluorescence conversion enables the absorption of additional green light by dye molecules by means of Förster resonance energy transfer between fluorescent compound donor and N719 dye acceptor. Owing to close fit between the emission peak of fluorophore and the absorption peak of N719 dye, the Förster resonance energy transfer effect enhances the incident photon to current conversion efficiency of the dye‐sensitized solar cells based on fluorophore‐doped TiO2 photoelectrodes. Improved power conversion efficiency (8.03–8.13%) is also achieved for the fluorophore‐doped (10−4 M) dye‐sensitized solar cells compared with a cell without the doping of fluorophore (7.63%). Copyright © 2013 John Wiley & Sons, Ltd.

Unlike traditional binary nanostructures that construct chemotherapy drugs and photodynamic therapy photosensitizers, we introduce a molecule with a chemo-photodynamic dual therapy function. A water-soluble aggregation-induced emission enhancement (AIEE) fluorogen, NV-12P, was designed and synthesized based on asymmetric 1,6-disubstituted naphthalene and can generate particular reactive oxygen species to undergo type I photodynamic therapy under irradiation. Furthermore, this compound can specifically localize in mitochondria and, after biological evaluation, can cause mitochondrial dysfunction and potent cytotoxicity to cancer cells but not normal cells. We conclude that this compound is a potential dual-toxic efficacy molecule because it exhibits selective dark cytotoxicity and efficient photodamage in cancer cells. Additionally, we also supported the optimal combinational treatment course for the best chemo-phototherapy efficacy.