Fluorescent Nanocomposite Prepared through Supramolecular Self-Assembly of a Tetraphenylethene Derivative and Polyoxometalate for Light-Emitting Diodes

Tetraphenylethene and its derivatives have become increasingly attractive as aggregation-induced emission luminogens (AIEgens) due to their superior luminescence efficiency and low contamination. In this paper, a tetraphenylethene derivative (4,4′,4″,4‴-(ethene-1,1,2,2-tetrayltetrakis(benzene-4,1-diyl)) tetrakis(1-allylpyridin-1-ium), TPE-1) synthesized with unique fluorescent properties, was integrated into a fluorescent nanocomposite with polyoxometalate (Na9[Eu(W5O18)2]·32H2O, EuW10) in an aqueous solution using an ionic self-assembly strategy. The TPE-1/EuW10 nanocomposite is composed of spherical particles with a uniform particle size of about 40 nm, and compared with the original material TPE-1, its quantum yield grows from 18.27% to 39.88%. The experimental results suggest that the negatively charged groups of EuW10 may interact electrostatically with the positively charged nitrogen atoms of TPE-1, leading to the aggregation of TPE-1 molecules to enhance the fluorescence. Mixing the TPE-1/EuW10 nanocomposite with commercially available blue and green phosphor can yield a white emitting phosphor with the CIE coordinate of (0.33, 0.34), which is close to the standard white light. This ionic self-assembly strategy of TPE-1 and EuW10 with easy preparation is of great significance for the simple construction of an AIE light-emitting system applicable to optoelectronic devices.