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Biosynthesized silver (Ag) and gold nanoparticles (Au NPs) were synthesized by using Punica granatum and Citrus reticulata extracts and these extracts act as stabilizer. The average sizes of the Silver and Gold NPs were in the range of 8–10 nm and 30–40 nm, respectively. The confirmation of NPs was done by UV-visible absorption spectra, X-ray diffraction (XRD), transmission electron microscope (TEM), and Fourier transform infrared spectra (FTIR) techniques. The luminescence studies of europium and samarium complexes with NPs were studied. Emission intensities of complexes with the presence of silver enhanced and quenched with gold due to the reabsorption. The toxicity and antimicrobial studies of nanostructures were studied.

Simple green synthesis of metal nanoparticles (Ag NPs) was prepared by using Raphanussativus leaf extract. This extract acts as reduce and stabilizing agent. The formation of silver NPs was confirmed and characterized by XRD, UV–visible absorption spectrum, TEM, and FTIR. The luminescence enhancement and quenching of Eu3+and Sm3+ ions were observed in the presence of silver NPs. The luminescence enhancement is owing to arise in the electric-dipole transition with alteration of the field around Ln3+ ions. Nonlinear studies in femtosecond (fs) and picosecond (ps) time scales have been studied by using the Z-scan technique. Third-order nonlinear optical susceptibility of silver nanoparticles was obtained with Degenerate Four-Wave Mixing (DFWM) in the fs regime. The lifetimes of lanthanum complexes were increased by the concentration of silver NPs and decreased for further silver. The high enhanced luminescence and nonlinear studies of green synthesized silver nanoparticles can be used in optics and bio applications.

Size-dependent optical properties of semiconductor cadmium tellurite (CdTe) quantum dots (QDs) were examined by UV–Visible absorption, photoluminescence, Transmission electron microscope (TEM) and [Formula: see text]-scan. Red shift in the wavelength was observed in absorption and photoluminescence as the size increased. The size of the CdTe QDs is in the range between 3[Formula: see text]nm and 6[Formula: see text]nm. Two-photon absorption with reverse saturable absorption varied with size in picosecond region due to exciton oscillator. CdTe QDs can be used as optical limiters in the region of visibility.