The features of well-conjugated and planar aromatic structures make π-conjugated luminescent materials suffer from aggregation caused quenching (ACQ) effect when used in solid or aggregated states, which greatly impedes their applications in optoelectronic devices and biological applications. Herein, we reduce the ACQ effect by demonstrating a facile and low cost method to co-assemble polycyclic aromatic hydrocarbon (PAH) chromophores and octafluoronaphthalene together. Significantly, the solid photoluminescence quantum yield (PLQYs) for the as-resulted four micro/nanococrystals are enhanced by 254%, 235%, 474 and 582%, respectively. Protection from hydrophilic polymer chains (P123 (PEO₂₀-PPO₇₀-PEO₂₀)) endows the cocrystals with superb dispersibility in water. More importantly, profiting from the above-mentioned highly improved properties, nano-cocrystals present good biocompatibility and considerable cell imaging performance. This research provides a simple method to enhance the emission, biocompatibility and cellular permeability of common chromophores, which may open more avenues for the applications of originally non- or poor fluorescent PAHs.

Here, we report a new Ti(IV)-based porous metal–organic framework (MOF) (NTU-9), which displayed strong absorption in the visible region with a bandgap of 1.72 eV. The electronic structure and bandgap were further investigated by DFT calculations. Photoelectrochemical studies indicated that NTU-9 is photoactive under visible light illumination (λ > 400 nm) and acts as a p-type semiconductor. The results demonstrated that Ti(IV)-based MOFs could be promising visible-light photocatalysts for energy conversion and environmental remediation.