Bücher von Houcine Labiadh

Zinc sulfide (ZnS) particles were synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infra-red (FT-IR) spectroscopies. The sizes of the crystallites were estimated using the Debye-Scherrer formula based on the XRD data. Zinc sulfide particles were screened for their antibacterial activity and for their antioxidant activity with 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (OH¿) and hydrogen peroxide (H2O2) scavenging activity, ferric reducing power (FRP) assay and ferrous ion chelating (FIC) methods. It was found that ZnS particles showed appreciate both antioxidant and antibacterial activity. In the last two decades, synthesis of nanoparticles has a rapid advancement. Among various classes of nanoparticles, semiconductor nanomaterials such as ZnS, have emerged as important materials with promising applications in nanotechnology.

Kwas 3-merkaptopropionowy zamkni¿ty rdze¿/otoczka ZnS:Cu(3%)/ZnS domieszkowane kropki kwantowe (QDs), gdzie syntetyzowane w temperaturze 95 °C w zasadowym roztworze wodnym z wykorzystaniem metod dopingu nukleacyjnego. W¿äciwo¿ci strukturalne i optyczne QD charakteryzowäy si¿ dyfrakcj¿ rentgenowsk¿ (XRD), która potwierdza kubiczn¿ mieszanin¿ fazow¿, natomiast transmisyjna mikroskopia elektronowa (TEM), która pokazuje, ¿e nanocz¿stki s¿ sferyczne. Spektroskopia UV-vis i spektroskopia fotoluminescencji (PL). Uzyskane QD prawie monodyspersyjne maj¿ przeci¿tn¿ ¿rednic¿ ca. 3,31 nm i strukturze krystalicznej mieszaniny cynku. D¿ugo¿¿ fali emisji PL by¿a ograniczona w przedziale od 500 do 510 nm, ale sprawno¿¿ kwantowa PL nanokrysztäów ZnS:Cu/ZnS rdze¿/pow¿oka wzros¿a do 5 %. Wyniki do¿wiadcze¿ pokazuj¿, ¿e metoda ta jest skuteczna w przygotowaniu kropek kwantowych ZnS:Cu/ZnS.

3-Mercaptopropionic acid capped core/shell ZnS:Cu(3%)/ZnS doped quantum dots (QDs) where synthesized at 95 °C in basic aqueous solution using the nucleation doping approach methods. The structural and optical properties of the QDs were characterized by X-ray diffraction (XRD) which confirms the cubic phase blende, whereas transmission electron microscopy (TEM) which shows the nanoparticles are spherical. UV¿vis spectroscopy and photoluminescence (PL) spectroscopy. The obtained nearly monodisperse QDs have an average diameter of ca. 3.31 nm and a zinc blende crystal structure. The PL emission wavelength was limited between 500 and 510 nm but PL quantum efficiency of ZnS:Cu/ZnS core/shell nanocrystals increased up to 5 %. The experimental results demonstrate that this method is effective for the preparation of ZnS:Cu/ZnS quantum dots.