Co-assembled photoactive organic molecules into layered double hydroxide as fluorescent fillers for silicone films

Abstract

In this study, photoactive organic molecules (PAO) and polymer stabilizer (anti-oxidant (AO) and light stabilizer (UV)) are co-intercalated into the galleries of layered double hydroxides (LDH) to form a series of new hybrid luminescent LDH fillers, LDH-AO/PAO and LDH-UV/PAO, adjusting the anion ratio of PAO (%). The structure of the hybrid materials is characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The optical properties of the hybrid materials and in particular their absolute photoluminescent quantum yields (PL QYab) are underlining that the series LDH-(AO or UV)/PAO is excited with varying degrees of efficiency by blue and/or UV-commercial LEDs. Interestingly, it demonstrates that UV and AO hydroxyl-bearing cyclic molecules used here as spacer to disperse PAO molecules are not deleterious to the luminescence. However, less cyclic AO spacer is here preferred to UV light stabilizer to avoid π-π stacking with PAO dyes. An optimal PAO concentration for each composition is determined for the highest PL QYab. Subsequently, the different samples are dispersed as fillers into silicone to obtain homogeneous luminescent composite films. These results highlight that LDH-(AO or UV)/PAO hybrid materials are suitable candidates to immobilize fluorescent organic dyes and that the associated films are potentially of interest as phosphors materials for several applications.