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Undoped and doped with nano-ZnO (Zn0.9X0.1O, X = Co, Cu and Mn) blended polymers (70% polyvinyl alcohol/30% polyvinyl pyrrolidone) were formed using solid-state reaction and casting methods. X-ray diffraction measurements were used to examine the incorporation of the nanofiller into the polymer matrix. Rietveld analysis showed an average crystallite size of 20 nm for ZnO with a little change upon doping Co, Cu, or Mn. The variations in the absorbance, extinction coefficient, refractive index, direct optical band gap energy, the single-oscillator energy, the oscillator strength and static refractive index of the blend with the nanofiller were studied in detail. The optical bandgap of the pristine blend, 4.97 eV, was reduced upon doping reaching a minimum of 4.82 eV for pure ZnO. The obtained values of electric characteristics and nonlinear optical properties are affected by the kind of dopant and the value of wavelength used. The reduction obtained in the optical band gap can nominate the doped blended polymers to be used as an absorbing layer in a solar cell to improve the efficiency of photovoltaic devices. Also, the enhancement of the nonlinear parameters nominates them to be applied in different nonlinear optical and photonic applications. The emitted fluorescence spectra depended on the excitation wavelength and the kind of dopants.

Nanocomposite (1−x) ZnMn2O4/xCdS (0.0 ≤ x ≤ 0.2) samples are prepared employing co-precipitation and thermolysis procedures. Phase analysis applying X-ray diffraction disclosed the presence of two phases: main ZnMn2O4 (ZMO) phase (~98%) and very minor CdS phase (~2%). The influence of alloying between ZnMn2O4 (ZMO) and CdS on the cell parameters and the phase percentage of the obtained phases is determined; the cell parameter (a) raised slightly but (c) parameter reduced with (x). Fourier transform infrared (FTIR) and XRD Rietveld analysis manifested the incorporation of Cd ions into the ZMO lattice. X-ray photoelectron spectroscopy (XPS) asserted the existence of Cd2+ and S− ions in the ZMO lattice and the valance states of Mn and Zn ions are determined. All optical parameters are improved as the CdS content (x) increased up to 15%, then decreased with a further increase in (x) in the composites. The photoluminescence (PL) intensity is enhanced as ZMO alloyed with CdS. The different emitted colors are also explored using PL technique. The modified properties nominate ZMO/CdS for different optoelectronic and display applications.

(1−x) CuCo2O4-xCuS (x = 0, 0.1, 0.25, 0.5) nanocomposite samples were prepared using hydrothermal and thermolysis procedures. The crystal structure and the percentages of phases formed in the nanocomposite samples were studied employing Fullprof software. X-ray photoelectron spectroscopy (XPS) was carried out to identify the different ions present in samples and their oxidation states. The specific capacitance is remarkably enhanced after adding CuS emphasizing the synergistic effect between CuCo2O4 and CuS. The optimum performance of 735 Fg−1 was achieved for 25% CuS. At a higher amount of CuS, the electrochemical activities become less compared with a low CuS amount. The supercapacitor electrode of 0.75CuCo2O4/0.25CuS exhibited high stability with a longer discharging time compared with pristine CuCo2O4 and CuS. Also, it maintained 88.9% of its initial Cs and consequently, this material can work as an excellent supercapacitor electrode. Electrochemical impedance spectroscopy (EIS) analysis was also performed.

Blended polymers, polyvinyl alcohol (PVA)/polyvinyl pyrrolidone (PVP), embedded with nano Sn0.75M0.25S2, (M = Y, Fe, Cr, V) were prepared using thermolysis and casting procedures. Rietveld refinement was used to investigate the structure and microstructure of the powder nano-filler Sn0.75M0.25S2, (M = Y, Fe, Cr, V). SEM images of 50%PVA/50%PVP doped with the powder samples revealed a homogeneous distribution of the nano-filler over the polymer blend. X-ray diffraction patterns exhibited small degree of crystallinity coupled with a diffuse scattering referring to an amorphous phase. Transmission FTIR spectra confirmed the incorporation of nano-filler into the blend matrix. The effect of nano-filler on the transmittance, optical absorption coefficient, extinction coefficient, refractive index, the optical bandgap, Urbach energy, steepness parameter, optical conductivity, the real and imaginary parts of the dielectric constant of the 50%PVA/50%PVP blend was studied using UV–vis spectrophotometry technique. Fluorescence (FL) spectra analysis revealed that the emitted color and Fl intensity depended on the kind of nano-filler and excitation wavelength.

(1-x)ZnMn2O4/xNiFe2O4 (x = 0, 0.05, 0.1, 0.15, 0.2) nanocomposite system was prepared using the sol–gel technique. Rietveld analysis revealed the presence of two phases ZnMn2O4 and NiFe2O4 for all composites, but with phase percentages different from nominated values of (x). The effect of alloying parameter (x) on the lattice parameters and crystallite size of the obtained phases was also examined. The oxidation states of different ions were determined using X-ray photoelectron spectroscopy (XPS) technique. For the prepared nanocomposite samples, the dependence of dielectric constant, impedance and electric modulus on the frequency and temperature was performed using complex impedance technique. It was found that the obtained samples have ferroelectric characteristics. The degree of correlation for the different nanocomposite samples was explored using ac conductivity.

Iron-doped nano ZnMn2O4 (ZnMn2-xFexO4, x = 0, 0.05, 0.15, 0.2) samples were formed using the sol–gel method. Rietveld refinement method revealed small changes in the cell parameters and crystallite size upon doping ZnMn2O4 with Fe. ZnMn2O4 is partially inverse spinel and it exhibited a normal spinel structure as it doped with Fe. The nano nature of the samples was confirmed using the high-resolution transmission electron microscope technique. The changes in the dielectric, complex impedance and complex modulus properties with doping, frequency and temperature were investigated using the complex impedance technique. Maxwell-Wagner model and Koop’s theory were used to explore the dielectric characteristics of the sample. The dielectric constant of 15% Fe-doped ZMO sample is larger than the dielectric of 10% Fe-doped one. The samples exhibited a ferroelectric nature at 60 °C. The a.c. conductivity of 15% Fe-doped sample is slightly higher than that of 10% Fe-doped sample. All doped samples exhibited the overlap large polarons (OLP) model. The doped samples have a single relaxation process. The activation energy of conduction was increased as the amount of Fe doping increased.

Nanocomposite (1 − x)CuS/(x)MnS samples (x = 0, 0.25, 0.5, 0.75, 1) were prepared by a simple thermolysis procedure at low temperature (250 °C). HighScor plus program and Rietveld profile method revealed that CuS crystallized in hexagonal phase, while MnS crystallized in hexagonal and cubic phases. The intermediate alloying ratios (x = 0.5, 0.75) have a cubic phase of MnS and a hexagonal phase of CuS, while sample with x = 0.25 has a hexagonal phase of CuS only. The phase percentage of MnS phase in the nanocomposite samples is always less than the nominal value proposed during the sample’s preparation. The MnS phase in the intermediate alloying ratios (x = 0.5, 0.75) has a larger crystallite size than the CuS phases. Composite samples (x = 0.5, 0.75) revealed two optical band gaps while sample with x = 0.25 showed only one optical band gap. The photoluminescence intensities for CuS@MnS nanocomposites were decreased as compared with either CuS or MnS samples. Nanocomposite (1 − x)CuS/(x)MnS samples emitted UV, violets, blue, green and yellow colors depended on the ratio between CuS and MnS mounts in the composite samples and the excitation wavelengths uses. The different kinds of defects in different samples were investigated also in detail.

Iron-doped nano CdS was prepared in air and underflow of nitrogen applying the thermolysis technique. The impact of air and nitrogen atmosphere on the crystallinity and the different structure parameters of the obtained samples was investigated using X-ray diffraction measurements and applying Rietveld method. Analysis revealed the presence of two phases for CdS; hexagonal wurtzite and cubic zincblende with phase percentages greatly affected with preparation conditions; sample obtained under N2 is almost pure hexagonal (97%). The particle morphology was investigated by FE-SEM, and the associated EDS spectra manifested elements percentages in accordance with those intended for preparation. The optical bandgap was greatly affected; compared with samples formed in air, it reduced upon doping with Fe as well as upon preparation under N2, it decreased from 2.58 eV for pristine CdS to 1.99 eV for Fe-doped CdS under N2. The photoluminescence (PL) intensity was also affected by the condition of preparation and iron doping. Pure and Fe-doped CdS samples emitted violet and blue colors. Density function theory (DFT) calculations were performed to explain the reason for the reduction of the optical bandgap upon doping CdS with Fe. The comparison between different electronic characteristics of pure and Fe-doped CdS samples was explored also by DFT calculation.

Ga0.9Al0.1FeO3 and Ga0.75Al0.25FeO3 samples were obtained using a solid-state reaction process. Phase analysis indicated that all samples are single phase having an orthorhombic structure. The effect of Al doping on the lattice parameters, the distortions in the tetrahedral and octahedral bond lengths and angles and cation distribution of different ions among the four crystallographic positions in GaFeO3 (GFO) was studied in detail applying Rietveld structural analysis; Al ions substituted Ga mostly at the octahedral site G2 with a small fraction residing at the Fe1 and Fe2 sites. The sample morphology was investigated by high-resolution scanning electron microscopy and the corresponding energy-dispersive x-ray analysis manifested element percentages in accordance with intended values. The influence of the doping amount, the frequency and temperature on the dielectric properties, ac conductivity, complex impedance and complex electric modulus of GFO was also investigated. Nyquist plots for both samples at different temperatures were studied. The activation energy of doped samples is in agreement with the activation energies of double ionized oxygen vacancies; it increased as the amount of Al doping GFO matrix increased.

CdS and Cd0.95Mn0.05S were synthesized using a thermolysis procedure in the air and underflow of nitrogen. Rietveld analysis for X-ray diffraction data revealed that all samples have two phases (hexagonal wurtzite and cubic zinc blende). The effect of Mn doping and the preparation conditions on the phase percentages, the crystallite size, lattice parameters and vibrational bands were investigated in detail. The optical band gap of CdS reduced when formed in N2 compared with sample formed in air. Upon doping with Mn, the optical band gap of samples (in air or nitrogen) exhibited a redshift. Density function theory calculation (DFT) revealed a semiconductor feature with a direct band gap for all samples except Mn-doped CdS with cadmium deficiency; it has a half metallic nature. DFT calculations manifested that for the Mn-doped samples, the optical conductivity was enhanced in the visible range considering sulfur deficiency, while considering Cd deficiency the sample has an optical conductivity response only in the IR region. The calculations were performed to examine the influence of Mn doping on the structure, optical, magnetic and electronic characteristics of CdS (stoichiometric and non- stoichiometric).

Solid solutions from $$(1-x){\mathrm{ZnMn}}_{2}{\mathrm{O}}_{4}/(x){\mathrm{MgFe}}_{2}{\mathrm{O}}_{4}$$ (x = 0.0, 0.1, 0.5, 0.9, 1.0) were obtained by a simple sol–gel procedure. A single-phase tetragonal spinel zinc manganite was identified by X-ray phase analysis for the samples x = 0.0 and 0.1, whereas a single-phase cubic spinel magnesium ferrite was identified for x = 0.5, 0.9, and 1.0. The formation of these phases was confirmed by the analysis of FTIR absorption spectra measured for the obtained samples. A scanning electron microscope was used to identify the different elements in the formed solid solution. Transmission electron microscope together with Rietveld profile method emphasized the nano-nature of the obtained samples. The influence of the composition parameter (x) on the optical properties of the solid solutions was explored utilizing UV–Vis diffuse reflectance spectroscopy measurements. The magnetic measurements revealed the conversion of the paramagnetic nature of ZnMn2O4 samples into ferromagnetic nature as it couples with MgFe2O4 sample in $$(1-x){\mathrm{ZnMn}}_{2}{\mathrm{O}}_{4}/(x){\mathrm{MgFe}}_{2}{\mathrm{O}}_{4}$$ solid solution. The supercapacitor performance of all samples was examined by cyclic voltammetry and galvanostatic charge–discharge studies.

Nanocomposites of CdS@CuS heterostructures were synthesized applying a simple chemical procedure. The structural characteristics of resulting nanocomposites (1 − x)CdS–xCuS (x = 0, 0.3, 0.5, 0.7 and 1) samples were inferred applying synchrotron X-ray diffraction (XRD), Fourier transform infrared (FTIR) and high-resolution transmission electron microscope techniques. The optical characteristics were deduced from the UV–Vis and photoluminescence (PL) spectroscopy techniques. XRD phase identification revealed CuS having the hexagonal phase P 63/m m c, while CdS in two phases: cubic major phase $$ F \bar{4} 3 m $$ and hexagonal minor phase P 63 m c. The phase percentage, the crystallite size, the lattice parameters and the ions coordinates of each phase are traced as a function of the alloying parameter (x). FTIR analysis revealed a change in the transmittance intensity of the vibration bands upon changing CdS/CuS ration in the nanocomposites matrix. UV–Vis absorption spectra were affected greatly by the ratio of CdS to CuS in the different composites. All composites materials exhibited two energy gaps lower than parent compounds. The PL emission of CdS sample is broader than CuS sample. The PL spectra of CdS@CuS nanocomposites samples revealed a broad emission with a redshift depending on the ratio between CdS and CuS in the matrix. All samples emitted UV, violet and blue colors, while CuS sample reveals UV and violet colors. The obtained properties of CdS@CuS nanocomposites, by changing the composition ratio, make them good candidates for enhanced visible light photocatalytic activity and solar energy applications.

Unprecedented analysis of the impact of high-level Al3+ substitution on the structural and magnetic properties of low-coercivity Co0.5Zn0.5AlxFe2−xO4 (0.3 ≤ x ≤ 0.8) nanoferrites prepared via autocombustion method is presented. Single-phase cubic structure has been assured for all samples using XRD patterns and FTIR spectra. Due to the notable difference in the ionic radii of Fe3+ and Al3+, structural defects are created for high substitution levels, which is to be balanced by cation redistribution and/or the appearance of Fe2+ and Co3+ cations. Rietveld analysis and size-strain plots were used to explain the non-monotonic change of the lattice parameter, microstrain and crystallite size. For the as-prepared samples, the estimated size ranged from 9 to 19 nm, which was confirmed by HRTEM images. Magnetic properties were deduced from M–H loops traced at room temperature. Saturation magnetization (MS) decreased with increasing Al3+ content while coercivity (Hc) was fluctuating. Based on the experimental data of XRD, FTIR, and VSM, a cation distribution has been proposed and tightly correlated with the structural and magnetic properties. The significant reduction of the lattice parameter and coercivity for the sample with x = 0.8 upon sintering process has been explained in the light of the cation distribution.

Non-stoichiometric ZnS nanomaterials were prepared using a thermolysis procedure by decreasing the stoichiometric amount of thiourea relative to the amount of zinc acetate as starting precursors: Zn(Ac)/(1−x) thiourea (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5). The high-resolution transmission electron microscope revealed the nanonature of the obtained samples. The X-ray diffraction analysis applying Rietveld method was carried out to explore the influence of Zn/S non-stoichiometry on the structural and microstructural properties of the crystalline phases in the samples. ZnO phase appeared for x ≥ 0.2 forming ZnS1–x/ZnO heterostructures; its percentage increased with increasing non-stoichiometric parameter (x). Incorporation of oxygen ions into the ZnS lattice compensating the sulfur deficiency was manifested by Fourier transform infrared spectroscopy. The UV–Vis analysis revealed the decrease in the bandgap of ZnS from 3.42 eV for x = 0.0 to 2.71 eV for x = 0.5, making these materials suitable for new applications. The influence of non-stoichiometric parameter (x) on the photoluminescence emissions of formed samples was examined; results indicated the spectrum shift towards higher wavelengths. Density function calculations were performed in order to compare the electronic and optical properties of sulfur-deficient ZnS0.9 (single phase) with the ZnS sample.

Nano-ZnMn2O4 and ZnMn2O4/MWCNT/graphene composites were prepared by solgel and ball-milling methods. The functional properties of the prepared samples were studied by applying various techniques. X-ray diffraction (XRD) Rietveld analysis indicated a single-phase ZnMn2O4 with a partially inverse spinel nanostructure (average size ≈ 7 nm), confirmed by TEM graphs, which revealed the morphology and particle nanosize distribution in samples. The samples were further characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The Gaussian fitting of Zn 2p and Mn 2p narrow XPS spectrum confirmed the cation distribution obtained from XRD Rietveld analysis. The galvanostatic cycling of the pure ZnMn2O4 electrode exhibited higher initial discharge capacity (~ 1978 mAh g−1) when cycled at 100 mA g−1 versus Li/Li+. Meanwhile, the cyclic voltammetry tests evidenced the enhanced Li-ion diffusion during the oxidation and reduction processes. The assembled ZnMn2O4/MWCNT/G cell delivered about 190 mAh g−1 of specific discharge capacity over 100 cycles with 65% capacity retention.

In this work, polymethylmethacrylate (PMMA) doped with SnS2, Sn0.75Fe0.25S2, and Sn0.75Cr0.25S2 nanoparticles films were prepared using both thermolysis and casting procedures. The purity, structural and shape of the nanofillers were confirmed by Rietveld refinement method. The compositional changes for nanocomposite films were studied by energy dispersive spectrometry technique. Nanoparticles morphology and particle size were examined by transmission electron microscopy (TEM) technique. Proper interactions between added nanofillers and the polymer matrix were discussed in detail by Fourier transform infrared spectroscopy technique (FTIR). The variations in the FTIR absorption bands position and their shape proved the effect of doping on the composite films. The effect of dopant elements on the thermal properties of PMMA polymer matrix has been investigated by thermogravimetric analysis (TGA). Results showed an improvement in the degradation temperature of doped polymers compared to undoped ones. Clear regular arrangements of images for nanoparticles and composite films have been represented by scanning electron microscopy (SEM). Different optical parameters have been examined using UV–vis spectroscopy technique. Due to the high transmittance values in the wavelength range of 320–800 nm, the formed composite films could be used as protective window layers for solar cells. The energy gap values decreased from 4.3 eV for undoped PMMA polymer to 4, 3.85, and 3.16 eV depending on the doping element.

Nano Er-doped CoFe2O4 has been synthesized by a sol–gel procedure at 700 °C. The effect of Er-doping on the lattice parameter, bond lengths and bond angles has been investigated using Rietveld refinement method. Bertau method has been used to determine the distribution of different cations between tetrahedral and octahedral sites. The saturation magnetization, remanence magnetization, coercivity and anisotropy constant were reduced as the amount of Er-doping increased. The variations of dielectric characteristics with changing Er-doped amount and frequency have been examined in details.

Different nano-oxides (Cr2O3, NiO, Co3O4) were added to polyvinyl alcohol/polyethylene glycol (70/30 wt%) blend. Rietveld profile analysis method was used to investigate the structure and microstructure characteristics of nano-oxide fillers. The effect of different nano-oxide fillers on the optical transparencies of the blend samples is confirmed. Co3O4 nano-oxide showed a higher uniform distribution within blends among other oxides. The variation of the absorption, the transmittance, the extinction coefficient, the refractive index and the energy gap (direct and indirect) of different blends based on different oxide fillers was examined by UV–Vis spectrophotometry technique. A single-term Sellmeier Oscillator approximation model was used to investigate the effect of excess oxygen atoms of the added nano-oxide fillers on the strength of the inter-band optical transitions, average excitation energy, average inter-band oscillator wavelength, the long-wavelength refractive index and the average oscillator strength. The effect of doping on the dielectric constant (real and imaginary) and optical conductivity of different blends behavior was investigated in detail as well.

Nano Cd1−xYxS and Cd1−xVxS (0 ≤ x ≤ 0.2) systems were synthesized by a thermolysis method. X-ray phase analysis indicated the presence of two phases, cubic and hexagonal structures, for some samples. The effect of doping on the cell parameters, Cd-tetrahedron dimension, crystallite size and the mixed phases’ percentages in the sample were examined applying X-ray Rietveld method. The energy gap of Y- or V-doped CdS was determined by ultraviolet spectroscopy technique. It is found out that the energy gap of V-doped CdS is less than the corresponding Y-doped CdS samples. Density function calculation (DFT) was used to confirm the decreasing in energy gap upon doping, and also to study the changes in absorption and dielectric properties of doped and undoped CdS samples in both cubic and hexagonal phases. The photoluminescence measurements revealed the presence of extra sub emissions spectra (yellow and green) upon doping CdS with Y or V compared with undoped CdS sample.

Nano-CuS doped with Mn or Fe (Cu1–x(Mn or Fe) x S; 0 ≤ x ≤ 0.2) was prepared by a thermolysis method. The structural, optical and magnetic properties were investigated using XRD synchrotron radiation, scanning electron microscope (SEM), ultraviolet spectroscopy (UV–Vis), photoluminescence (PL) and vibrating sample magnetometer (VSM). Diffraction patterns manifested a single phase of CuS hexagonal structure with a minor phase Cu2S in case of Fe doped and only a single phase in case of Mn-doped CuS samples. Analysis indicated a necessity of good diffraction patterns and Rietveld analysis for phase’s determination. The changes in bond lengths, lattice parameters, and microstrain were determined by Rietveld method and correlated with the measured physical properties. Energy gaps showed an irregular change with increased amount of Mn doped while they exhibited a regular decrease as the amount of Fe increased in CuS matrix. The PL emissions revealed three sub-violet, (two violet, one blue) and (two violet, one blue, one green) emitted peaks for pure, Mn- and Fe-doped CuS, respectively. The PL intensity was enhanced for x = 0.1 doped Mn or Fe then it quenched by further doped. Bare CuS showed diamagnetic properties; while Mn- and Fe-doped samples had paramagnetic properties.

Nano-nickel ferrites defected by vanadium doping (NiV x Fe2−1.67xO4, 0 ≤ x ≤ 0.25) were prepared using a simple sol gel method. Rietveld analysis revealed a nonmonotonic change in lattice parameter, oxygen parameter and magnetization upon doping with vanadium. Cation distributions suggested from either Rietveld analysis or from experimental magnetic moments were in a good agreement. For low doping values (x = 0.05), vanadium was residing mainly in octahedral sites, while for samples with vanadium content (x ≥ 0.1) a significant part of vanadium ions resided at tetrahedral sites; a result which has been confirmed by the analysis of Fourier-transform infrared (FTIR) spectrums obtained for the samples. The transmission electron microscope (TEM) image showed fine spherical particles with size of ∼ 11 nm. All samples showed a superparamagnetic nature with a nonmonotonic change of either magnetization (MS) or coercivity (HC) with the content of nonmagnetic V5+. The cation occupancies indicated presence of an enormous number of vacancies through doping with high valence cation V5+, making present samples potential electrodes for Li- or Na-ion batteries.