الفهرس 
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Abstract
The nanocomposite exhibit unique physical properties that are not found in their bulk counterpart. The synthesis structure which contains plasmonic metallic core metallic particles such as Silver (Ag) and a shell of CdS semiconductor has the combined properties of quantum dots and the metallic particles. The semiconductor nanoparticles such as CdS with different particle size have been synthesized by organometallic pyrolysis method. The X-Ray diffraction pattern of semiconductor quantum dots shows a pure wurtizte structure. The absorption spectra of QDs at different sizes have been investigated during the course of chemical preparation. The particle sizes between 2.34 nm to 3.72 nm have been calculated from optical band gap first excitonic peak). A new method has been developed to grow plasmonic semiconductor of Ag/CdS nanocomposites at which a metallic core has been used as a seed in order to form a nanoshell of CdS around. The surface plasmon (SP) bands of the metallic core show a decrease in amplitude and broadening of the width as the semicondcutor shell thickness increases. The optical properties of these novel nanohybrids have been investigated and discussed in details. The effect of capping agent, precursors type and their concentration on the particle growth and final shape has been studied. The photostability of these novel materials has been studied upon irradiation of different doses of UV light. The photocatalytic activity of these novel nanocomposites has been examined via photodegradation of methylene blue and compared to that of the pure component of the metal particles and quantum dots. It was clear that the photocatalytic activity of the plasmonic-semicondcutor nanohybrid is more efficient photocatalyst compared to metallic nanoparticles or quantum dots themselves due to increasing the charge separation and the absorption.