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The study herein is directed toward the tuning of various properties of recyclable and biocompatible polymer: chitosan (CS) via incorporating the variable wt% of r‐GO in the polymer. The CS/r‐GO polymer nanocomposites (PNCs) are prepared in the form of free‐standing film by solution mixing and casting technique. To search the potential applications, the prepared PNCs are characterized in terms of structural, photoluminescence (PL), surface morphology, optical, and Raman spectra. The crystalline size and microstrain both are enhanced with rise in wt% of r‐GO nanofiller. Raman spectra confirm that as the wt% of r‐GO increases, there is a minor shift toward a smaller wavenumber in the locations of the D, G, and 2D bands, while the intensity ratios (ID/IG$\left(\right. I_{\text{D}} / I_{\text{G}}$) increase. Field‐emission scanning electron microscopy results are capable of offering details regarding the surface quality for the interface purposes. The characteristic peaks and their broadening in PL spectra, chromaticity coordinates, dominant wavelength, and correlated color temperature are altered with variation of r‐GO wt.%. The optical bandgap, refractive index, and Urbach energy are found to tune with varying the nanofiller wt.%. These results suggest that CS/r‐GO PNC may be the potential candidate for possible application in fabricating the tunable optoelectronic devices. [ABSTRACT FROM AUTHOR]

Motivated from the extraordinary properties of CeO2 nanomaterial, this article is directed toward the synthesis of recyclable polyvinyl alcohol–CeO2 polymer nanocomposite with variable wt% of CeO2 and investigating their improvements in structural, electrical, optical, and surface properties. The crystalline size and micro‐strain are measured using X‐ray diffraction (XRD) data. Ultraviolet–visible–near‐infrared spectrophotometer is used to study the optical characteristics. Absorbance with redshift is found to enhance; while optical bandgap is reduced from 2.51 to 2.36 eV on increasing wt% of CeO2 nanofiller. The mechanism of reduction in bandgap is supported by the XRD analysis. Refractive index is found to vary from 2.54 to 2.59 and the range of Urbach energy varies from 1.19 to 0.42 eV on increasing the amount of nanofillers. Surface morphology, dielectric constant, and electrical conductivity are also found to improve with increasing wt% of nanofiller. The dielectric constant is improved from 60 to 120 at 1.5 Hz. The rise in conductivity with increasing wt% of CeO2 and rising frequency is due to the enhancement of mobility of the charge carriers and ionic hopping mechanism in conduction process. Characterization outcomes suggest that the prepared composites can be claimed as useful in fabricating the flexible optoelectronic devices. [ABSTRACT FROM AUTHOR]

The tunability of the optical gain characteristics of the AlN/GaN/InAlN quantum well heterostructure under uniaxial and biaxial pressures is reported. To study the tunability, pressures on the designed heterostructure are applied in the range of 1–4 GPa along different orientations, i.e., (001), (100), and (110). Under these pressures, the gain characteristics are computed. To perform the calculations for the gain characteristics, the well‐known k⋅p method is adopted. The optical gain is computed under uniaxial and biaxial pressures and the results are analyzed thoroughly. Quantitatively speaking, the amount of pressure (1–4 GPa) along z‐direction (i.e., 001) is suitable to make significant enhancement in the peak gain (i.e., from ≈7000 to ≈8000 cm−1) with the variation in transition wavelength from ≈1347 to ≈1512 nm. While the (100) and (110) oriented pressures having the range 1–4 GPa reduce the peak gain from ≈7100 to ≈5800 cm−1, and from ≈3550 to ≈3410 cm−1, respectively. On comparison of the results, it is concluded that only z‐direction pressure is useful for enhancing the gain characteristics with fine tuning of the transition wavelengths. Consequently, the designed heterostructure can be tuned with enhanced peak gain having red shift wavelength. [ABSTRACT FROM AUTHOR]

This article reports the synthesis of MnO2/Mn2O3 nanocomposite, which can be used in forming the anode for supercapacitor applications. The MnO2/Mn2O3 nanocomposites are synthesized via the sol–gel route and are characterized in context of structural parameters by X‐ray diffraction technique, field emission‐scanning electron microscopy (FE‐SEM), and supercapacitive behavior by cyclic voltammetry (CV) , galvanostatic charging and discharging (GCD), and electrochemical impedance spectroscopy. The spinel structure of MnO2/Mn2O3 nanocomposite with space groups Ia3 and I4/m for Mn2O3 and MnO2 nanocomposite is confirmed by the Rietveld refinement, respectively. The FE‐SEM micrographs reveal the nanosphere‐type shape of the MnO2/Mn2O3 nanocomposite. According to outcomes of electrochemical measurements, the nanocomposite exhibits good capacitive behavior in aqueous electrolyte KOH, demonstrating the highest specific capacitance (763 F g−1) at 1 Ag−1 current density from GCD. In CV, it has shown excellent performance with specific capacitance (642.93 F g−1) at 10 mV s−1. Additionally, the prepared nanocomposite‐enhanced electrolyte ion interaction may cause rapid charging and discharging, even at low current densities. [ABSTRACT FROM AUTHOR]