In this work, the optical properties of silver nanoparticles (AgNPs) were explored using Mie theory compared with the experimental AgNPs using the chemical reduction method. Mie’s theory is suited for accurately evaluating the scattering, absorption, and extinction cross-sections of spherical AgNPs. Therefore, the wavelength of localized surface plasmon resonance (LSPR) in the optical spectra of the spherical AgNPs was calculated. The experimental AgNPs have a spherical shape with an average particle size of 30 nm. In addition, the crystalline structure of AgNPs was found to be cubic with fcc structure with lattice constant $$a=$$a = 4.155 Å. Moreover, the excitation of the LSPR of the AgNPs was simulated using the finite-difference time-domain (FDTD) method at different wavelengths to explore the LSPR phenomena. The results show that spherical AgNPs are the most widely used materials in biosensors, biomedicine, optoelectronic devices, and solar cells due to their surface plasmon resonances in the visible spectrum region.

Sol-gel technique is used to synthesize as-grown zinc oxide (ZnO) and iron-nickel (Fe-Ni) co-doped ZnO thin films deposited on glass substrates using dip coating technique. The structural properties and crystal imperfections of as-prepared thin films are investigated. We performed the structural analysis of films using X-ray diffraction (XRD). The XRD analysis reveal that the as-prepared films exhibit wurtzite structure. Furthermore, XRD-line profile analysis is performed to study the correlation between structural properties and imperfections of the nanocomposite thin films. The crystallite size and microstrains parameters are predicted using the Williamson–Hall method. We found that the crystallites size increases as the co-doped (Fe-Ni) concentration is increased. However, microstrains of the nanocomposite films decreases as (Fe-Ni) concentration is increased. The optical properties of the (Fe-Ni) co-doped nanocomposite films are investigated by performing UV-Vis (250 nm–700 nm) spectrophotometer measurements. We found that as the (Fe-Ni) concentration level is steadily increased, transmittance of the undoped ZnO thin films is decreased. Remarkably, refractive index of undoped ZnO thin films is found to exhibit values extending from 1.55 to1.88 that would increase as (Fe-Ni) concentration is increased.

We report the synthesis of hybrid thin films based on Poly(MethylMethAcrylate) (PMMA) and Poly(VinylAlcohol) (PVA), doped with different concentrations of titanium dioxide nanoparticles (TiO₂ NPs). As-prepared thin films of (PMMA-PVA) doped by TiO₂ NPs (wt.% = 2%, 4%, 8%, and 16%) are deposited on glass substrate. Transmittance (T%), reflectance (R%), absorption coefficient (α), optical constants (n and k), and optical dielectric functions (ε₁ and ε₂) are deduced using the experimental transmittance and reflectance spectra. Furthermore, a combination of classical models such as Tauc, Urbach, Spitzer-Fan, and Drude models are applied to calculate the optical and optoelectronic parameters and the energy gaps of the prepared nanocomposite thin films. The optical bandgap energy of PMMA-PVA thin film is found to be 4.101 eV. Incorporation of TiO₂ NPs into PMMA-PVA polymeric thin films leads to a decrease in the optical bandgap and thus bandgap engineering is possible. Fourier-transform infrared spectroscopy (FTIR) transmittance spectra of thin films are measured and interpreted to identify the vibrational modes. To elucidate the chemical stability, thermogravimetric (TGA) curves are measured. We found that (PMMA-PVA)/TiO₂ NPs polymeric thin films are thermally stable below 110 °C enable them to be attractive for a wide range of optical and optoelectronic applications.

Undoped ZnO and group III (B, Al, Ga, and In)-doped ZnO thin films at 3% doping concentration level are dip-coated on glass substrates using a sol-gel technique. The optical properties of the as-prepared thin films are investigated using UV–Vis spectrophotometer measurements. Transmittance of all investigated thin films is found to attain high values of ≥80% in the visible region. We found that the index of refraction of undoped ZnO films exhibits values ranging between 1.6 and 2.2 and approximately match that of bulk ZnO. Furthermore, we measure and interpret nonlinear optical parameters and the electrical and optical conductivities of the investigated thin films to obtain a deeper insight from fundamental and practical points of view. In addition, the structural properties of all studied thin film samples are investigated using the XRD technique. In particular, undoped ZnO thin film is found to exhibit a hexagonal structure. Due to the large difference in size of boron and indium compared with that of zinc, doping ZnO thin films with these two elements is expected to cause a phase transition. However, Al-doped ZnO and Ga-doped ZnO thin films preserve the hexagonal phase. Moreover, as boron and indium are introduced in ZnO thin films, the grain size increases. On the other hand, grain size is found to decrease upon doping ZnO with aluminum and gallium. The drastic enhancement of optical properties of annealed dip-synthesized undoped ZnO thin films upon doping with group III metals paves the way to tune these properties in a skillful manner, in order to be used as key candidate materials in the fabrication of modern optoelectronic devices.