Tunable Photophysical Behavior of a Novel Fluorescent Probe by Silver/Gold and Core–Shell NPs

Abstract

The photophysical and photochemical behaviors of a novel fluorescent probe, namely 5-(4-(dimethylamino)phenyl)-1-(thiophen-2-yl)penta-2,4-dien-1-one (DMATP), were tuned by solvent effects and colloidal nanoparticle studies. Spectral data show that increasing the solvent polarity results in a significant solvatochromic shift in both the absorption and emission maxima. Also, the effect of deuteration on the photophysical properties of DMATP has been discussed by studying the optical absorption and emission properties of DMATP in nondeuterated solvent like MeOH and deuterated one like MeOD. Additionally, the spectral behavior of the investigated DMATP was tuned by noble nanoparticles such as Au, Ag, and Au@Ag core–shell. Firstly, the noble nanoparticles Au, Ag, and Au@Ag core–shell were synthesized and characterized using UV–vis spectroscopy and transmission electron microscopy (TEM). The absorption band of Ag and Au NPs showed plasmon peaks at 415 and 526 nm, respectively, confirmed the formation of NPs. However, the absorption spectra of Au@Ag core–shell show no evidence of an absorption peak at 526 nm, which was visible for AuNPs, and a blue shifted band at 402 nm has been observed, confirming that the Ag covered the Au seeds to create a bimetallic core–shell configuration nanoparticle. The interactions of DMATP with Au, Ag, and Au@Ag core–shell NPs were also studied based on fluorescence enhancement. The observed improvement in the spectral behaviors of DMATP and the high binding constants by the used NPs and its core–shell suggested that this dye can serve as candidates for many applications such as biological sensing and light-emitting diodes. Finally, the catalytic activity of the synthesized Au@Ag core–shell NPs for the degradation of methyl red has been employed. The obtained products may also have many potential applications in optical, magnetic, biochemical, and biomedical fields.