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In this research, direct band gap polymer composites with amorphous phase, which are imperative for optoelectronic devices applications were synthesized. The solution cast technique was used to produce polyethylene oxide (PEO)/calcium titanate (CaTiO 3 ) nanocomposite (NC) films. The X-ray diffraction (XRD) confirms the growth of amorphous nature within PEO with CaTiO 3 addition. The optical band gaps of pure PEO and PEO/CaTiO 3 NC films were calculated using analysis of ultraviolet-visible (UV-Vis) spectra. The change in absorption edge toward lower photon energy is evidence of polymer modification. The dispersion behavior of the refractive index of PEO was manipulated to a higher wavelength upon doping with CaTiO 3 . Upon adding CaTiO 3 to the pure PEO polymer, the dielectric constant and refractive index were considerably modified. The band gap shifts from 4.90 eV to 4.19 eV for the PEO incorporated with an optimum portion of 8 wt. % of CaTiO 3 . The types of the electronic transition in composite samples were specified, based on the Taucs model and the optical dielectric loss. The alteration of UV/Vis absorption spectra of the NC film was considered a suitable candidate to be applied in nanotechnology-based devices. The spherulites ascribed to the crystalline phase were distinguished through the optical microscopy (OM) study.

The influence of dispersing Al-metal complex on the optical properties of PVA was investigated using UV-visible spectroscopy. Polymer composite films with various Al 3+ -complex amounts in the PVA matrix were arranged by solution casting technique by means of distilled water as a widespread solvent. The formation of Al 3+ -metal complex was verified through Ultraviolet-visible (UV-Vis) and Fourier-transform infrared spectroscopy (FTIR) examinations. The addition of Al-complex into the polymer matrix led to the recovery of the optical parameters such as dielectric constant ( ε r and ε i ) and refractive index ( n ). The variations of real and imaginary parts of complex dielectric constant as a function of photon wavelength were studied to calculate localized charge density values ( N/m *), high-frequency dielectric constant, relaxation time, optical mobility, optical resistivity, and plasma angular frequency ( ω p ) of electrons. In proportion with Al 3+ -complex content, the N/m * values were amplified from 3.68 × 10 55 kg -1 m -3 to 109 × 10 55 kg -1 m -3 . The study of optical parameters may find applications within optical instrument manufacturing. The optical band gap was determined from Tauc's equation, and the type of electronic transition was specified. A remarkable drop in the optical band gap was observed. The dispersion of static refractive index ( n o ) of the prepared composites was analyzed using the theoretical Wemple-DiDomenico single oscillator model. The average oscillator energy ( E o ) and oscillator dispersion energy ( E d ) parameters were estimated.

In this work, plasticized polymer electrolyte films consisting of chitosan, ammonium nitrate (NH 4 NO 3 ) and glycerol for utilization in energy storage devices was presented. Various microscopic, spectroscopic and electrochemical techniques were used to characterize the concerned electrolyte and the electrical double-layer capacitor (EDLC) assembly. The nature of complexation between the polymer electrolyte components was examined via X-ray diffraction analysis. In the morphological study, field emission scanning electron microscopy (FESEM) was used to investigate the impact of glycerol as a plasticizer on the morphology of films. The polymer electrolyte (conducting membrane) was found to have a conductivity of 3.21 × 10 -3 S/cm. It is indicated that the number density ( n ), mobility ( μ ) and diffusion coefficient ( D ) of ions are increased with the glycerol amount. The mechanism of charge storing was clarified, which implies a non-Faradaic process. The voltage window of the polymer electrolyte is 2.32 V. It was proved that the ion is responsible for charge-carrying via measuring the transference number (TNM). It was also determined that the internal resistance of the EDLC assembly lay between 39 and 50 Ω. The parameters associated with the EDLC assembly are of great importance and the specific capacitance ( C spe ) was determined to be almost constant over 1 to 1000 cycles with an average of 124 F/g. Other decisive parameters were found: energy density (18 Wh/kg) and power density (2700 W/kg).

In the present work it was shown that low lattice energy ammonium salts are not favorable for polymer electrolyte preparation for electrochemical device applications. Polymer blend electrolytes based on chitosan:poly(ethylene oxide) (CS:PEO) incorporated with various amounts of low lattice energy NH 4 BF 4 ammonium salt have been prepared using the solution cast technique. Both structural and morphological studies were carried out to understand the phenomenon of ion association. Sharp peaks appeared in X-ray diffraction (XRD) spectra of the samples with high salt concentration. The degree of crystallinity increased from 8.52 to 65.84 as the salt concentration increased up to 40 wt.%. These are correlated to the leakage of the associated anions and cations of the salt to the surface of the polymer. The structural behaviors were further confirmed by morphological study. The morphological results revealed the large-sized protruded salts at high salt concentration. Based on lattice energy of salts, the phenomena of salt leakage were interpreted. Ammonium salts with lattice energy lower than 600 kJ/mol are not preferred for polymer electrolyte preparation due to the significant tendency of ion association among cations and anions. Electrical impedance spectroscopy was used to estimate the conductivity of the samples. It was found that the bulk resistance increased from 1.1 × 10 4 ohm to 0.7 × 10 5 ohm when the salt concentration raised from 20 wt.% to 40 wt.%, respectively; due to the association of cations and anions. The low value of direct current (DC) conductivity (7.93 × 10 -7 S/cm) addressed the non-suitability of the electrolytes for electrochemical device applications. The calculated values of the capacitance over the interfaces of electrodes-electrolytes (C 2 ) were found to drop from 1.32 × 10 -6 F to 3.13 × 10 -7 F with increasing salt concentration. The large values of dielectric constant at low frequencies are correlated to the electrode polarization phenomena while their decrements with rising frequency are attributed to the lag of ion polarization in respect of the fast orientation of the applied alternating current (AC) field. The imaginary part of the electric modulus shows obvious peaks known as conduction relaxation peaks.

In the current paper, ion transport parameters in poly (vinyl alcohol) (PVA) based solid polymer electrolyte were examined using Trukhan model successfully. The desired amount of lithium trifluoromethanesulfonate (LiCF 3 SO 3 ) was dissolved in PVA host polymer to synthesis of solid polymer electrolytes (SPEs). Ion transport parameters such as mobility (μ), diffusion coefficient ( D ), and charge carrier number density ( n ) are investigated in detail using impedance spectroscopy. The data results from impedance plots illustrated a decrement of bulk resistance with an increase in temperature. Using electrical equivalent circuits (EEC), electrical impedance plots (ZivsZr) are fitted at various temperatures. The results of impedance study demonstrated that the resistivity of the sample decreases with increasing temperature. The decrease of resistance or impedance with increasing temperature distinguished from Bode plots. The dielectric constant and dielectric loss values increased with an increase in temperature. The loss tangent peaks shifted to higher frequency region and the intensity increased with an increase in temperature. In this contribution, ion transport as a complicated subject in polymer physics is studied. The conductivity versus reciprocal of temperature was found to obey Arrhenius behavior type. The ion transport mechanism is discussed from the tanδ spectra. The ion transport parameters at ambient temperature are found to be 9 × 10 -8 cm 2 /s, 0.8 × 10 17 cm -3 , and 3 × 10 -6 cm 2 /Vs for D , n , andμ respectively. All these parameters have shown increasing as temperature increased. The electric modulus parameters are studied in an attempt to understand the relaxation dynamics and to clarify the relaxation process and ion dynamics relationship., Competing Interests: The authors declare no conflict of interest.

In this work, the role of poly(vinyl alcohol) (PVA) blending on structural and electrical properties of chitosan:silver nitrate systems is studied. The X-ray diffraction (XRD) results show that the crystalline phase of chitosan (CS) is greatly scarified by silver nitrate (AgNt) salt. The crystalline domain of CS:AgNt is more broadened at 10 wt % of PVA. The spike and semicircular arcs can be separated in impedance plots. At high temperatures, the spike regions remained. The direct current (DC) conductivity was calculated from the bulk resistance obtained from the impedance plots. The dielectric constant and DC conductivity versus PVA content exhibited similar behavior. The maximum DC conductivity at ambient temperature was 1.1 × 10 -6 S/cm for 10 wt % of PVA. The DC ionic conductivity increased to 9.95 × 10 -5 S/cm at 80 °C. Above 10 wt % of PVA, the drop in DC conductivity and dielectric constant were observed due to the increase in viscosity. Shifting of relaxation peaks towards the lower frequency revealed the increase of resistivity of the samples. The linear increase of DC conductivity versus 1000/T indicated that ion transport followed the Arrhenius model. The incomplete semicircular arc in Argand plots indicated the non-Debye type of relaxation process. The Argand plots were used to distinguish between conductivity relaxation and viscoelastic relaxation. Three regions were distinguished in the alternating current (AC) spectra of the blend electrolyte samples. The plateau region in AC spectra was used to estimate the DC conductivity. The estimated DC conductivity from the AC spectra was close to those calculated from the impedance plots., Competing Interests: The authors declare no conflict of interest.

In the present work, a novel method is exhibited for tuning the surface plasmon resonance (SPR) peaks of silver nanoparticles based on chitosan-Poly(vinyl alcohol) blend polymer nanocomposites. Silver nanoparticles were synthesized by in situ method through the chitosan host polymer. The absence of crystalline peaks of PVA in the blend system indicated the occurrence of miscibility between CS and PVA polymers. The UV⁻vis spectra of CS:AgNt samples shows SPR bands with weak intensity. Obvious tuning in SPR peaks of silver nanoparticles occurred when different amounts of PVA polymer incorporated to the CS:AgNt system. The appearance of distinguishable crystalline peaks of Ag° nanoparticles at 2θ = 38.6° and 2θ = 44.2° in the blend system reveals the role of polymer blending in the enhancement of SPR peaks of silver nanoparticles. Silver nanoparticles synthesized in this work with enhanced SPR peaks are important in various applications and areas such as optoelectronic devices. The TEM images show dispersed silver nanoparticles. The dielectric constant of PVA is higher than that of chitosan. The result of dielectric constant study validates the Mie model which reveals the fact that the dielectric constant of the surrounding material has a great effect on the SPR peak intensity of nanoparticles.

In this study, the role of ion dissociation on formation of silver nanoparticle and DC conductivityin PVA:AgNO₃ based solid polymer electrolyte has been discussed in detail. Samples of silver ion conducting solid polymer electrolyte were prepared by using solution cast technique. Absorption spectroscopy in the ultraviolet⁻visible (UV⁻Vis) spectral region was used to investigate the formation of silver nanoparticles. Broad and sharp peaks due to plasmonic silver nanoparticles subjected to ion dissociation have been observed. The influence of dielectric constant on the intensity of surface plasmonic resonance (SPR) peaks attributed to silver nanoparticles was discussed. From impedance plots, the diameter of high frequency semicircle was found to be decreased with increasing salt concentration. The DC conductivity in relation to the dielectric constant was also explained. From the AC conductivity spectra, the dc conductivity was estimated to be close to that calculated from the bulk resistance. The temperature dependence of the DC conductivity was studied and found to follow Arrhenius equation within two distinguished regions. The AC conductivity at different temperatures has been studied to comprehend the ion conduction mechanism. The AC conductivity against frequency was found to obey the universal power law of Jonscher. Three distinct regions were recognized from the spectra of AC conductivity. The frequency exponent ( S ) was calculated for the dispersive region of the measured AC conductivity spectra. Various models were discussed to explain the behavior of S value with temperature. The behavior of S value with temperature was then used to interpret the DC conductivity pattern against 1000/T. Finally, from the comparison of calculated activation energy ( E a ) and maximum barrier height ( W m ), deep insights into ion conduction mechanism could be grasped., Competing Interests: The authors declare no conflict of interest.

In this paper, the sample preparation of polymer nanocomposites based on methyl cellulose (MC) with small optical bandgaps has been discussed. Copper monosulfide (CuS) nanoparticles have been synthesized from the sodium sulphide (Na₂S) and copper chloride (CuCl₂) salts. Distinguishable localized surface resonance plasmon (LSRP) absorption peaks for CuS nanoparticles within the 680⁻1090 nm scanned wavelength range were observed for the samples. An absorption edge ( E d ) was found to be widely shifted to a lower photon energy region. A linear relationship between the refractive index of the samples and the CuS fraction was utilized to describe the distribution of the particle. The optical bandgap of MC was reduced from 6.2 to 2.3 eV upon the incorporation of 0.08 M of CuS nanoparticles. The optical dielectric loss, as an alternative method, was used successfully to estimate the optical bandgap. Moreover, the electronic transition type was identified by using Tauc's extrapolation method. The plots of the optical dielectric constant and energy bandgap as a function of the CuS concentration were utilized to examine the validity of the Penn model. For the nanocomposite samples, the Urbach energy was found to be increased, which can be evidence for a large possible number of bands-to-tail and tail-to-tail transitions. However, from the X-ray diffraction (XRD) analysis, it was also found that the synthesized CuS nanoparticles disrupted the crystallinity phase of the MC polymer. Finally, fourier transform infrared (FTIR) spectroscopy for the samples was also performed. Significant decreases of transmittance intensity as well as band shifting in the FTIR spectra were observed for the doped samples., Competing Interests: The authors declare no conflict of interest