ايجاد نانوذرات نقره در شيشه‌هاي تبادل يون شده و بررسي برهمكنش نانوذرات نقره با نانوذرات يديدنقره

Creation of silver nanoparticles in ion-exchanged glass an‎d investigating the interaction of silver nanoparticles an‎d the iodide nanoparticles

فيزيك

Silver nanoparticles are suitable can‎didates for light trapping due to the presence of strong surface plasmon resonance in the visible region. Ag+/Na+ ion-exchanged glasses provide an appropriate substrate for the formation of silver nanoparticles an‎d the modification of their optical characteristics due to their unique optical properties. Annealing of Ag+/Na+ ion-exchanged glass results in the formation of silver clusters an‎d nanoparticles within the glass matrix, which induces surface plasmon resonance in the wavelength range of 400 to 450 nm. Silver iodide is a semiconductor material whose excitonic absorption peak lies in the wavelength range of 420 to 430 nm, depending on the thickness of the silver iodide layer. The excitonic wavelength of silver iodide shows good overlap with the surface plasmon resonance wavelength of silver nanoparticles in ion-exchanged glasses. In a hybrid metal–semiconductor system, when the excitonic peak of the semiconductor an‎d the surface plasmon resonance of the metallic nanoparticles overlap well, the optical properties of the system are modified. In this dissertation, a hybrid silver iodide–silver system was created by fabricating Ag+/Na+ ion-exchanged glasses using a thermal process with a composition of 4 wt% silver nitrate an‎d 96 wt% sodium nitrates. The glasses were then annealed at temperatures of 400, 420, 440, 460, an‎d 480 °C. Analysis of the optical absorption an‎d transmittance spectra of these samples showed that with increasing annealing temperature, the surface plasmon resonance peak shifts toward longer wavelengths, indicating the formation of larger silver clusters an‎d nanoparticles in the ion-exchanged glasses. By depositing an 8 nm-thick silver iodide layer onto the annealed samples, the surface plasmon resonance peak of these samples shifted further toward longer wavelengths. Additionally, the 8 nm-thick silver iodide film induced a slight change in the energy ban‎d gap of the samples. The Urbach energy, which is a measure of structural disorder in a quasi-amorphous structure, was measured for all samples. With increasing annealing temperature, the Urbach energy increased, indicating a reduction in disorder an‎d an increase in crystalline silver nanoparticles within the glass. The deposition of an 8 nm-thick silver iodide layer on the samples did not lead to a significant change in the Urbach energy. Ion-exchanged glasses exhibit high photoluminescence due to the presence of silver ions an‎d silver nanoclusters. However, the photoluminescence of the sample annealed at 480 °C shows a strong reduction owing to the presence of large silver nanoparticles. The 8 nm-thick silver iodide layer leads to changes in the photoluminescence intensity an‎d a shift in the photoluminescence peak, which strongly depend on the wavelength of the excitation light beam.

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