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Abstract: Films of polyaniline (PANI) and PANI-nano ZnO composites have been synthesized by solution casting technique. Fourier transform infrared spectroscopic studies of PANI and PANI-nano ZnO composite films indicated the presence of interaction between nano ZnO particles and molecular chains of PANI. Dielectric properties of the PANI and composite films have been investigated in the frequency range of 8.0–12.0GHz. The real part of permittivity (ɛ′) and loss factor (tan δ) were found to decrease in PANI-nano ZnO composite films. The decreasing behavior of ɛ′and tan δ may be attributed to the interaction between nano ZnO particles and PANI molecular chains. The interaction between PANI chains and surface of ZnO nano particles restricts the motion of the dipoles and leads to the decrease of ɛ′and tan δ of the composite films. [Copyright &y& Elsevier]

• The PVDF, PVDF-MoS 2 , and PVDF-rGO-MoS 2 nanocomposites were fabricated by the polymer solution casting method. • The synthesized materials and thin films were examined using XRD, FTIR, and PFM techniques. • The fabricated piezoelectric nanogenerator of MoS 2 -rGO-PVDF nanocomposite showed enhanced output current and voltage. [Display omitted] Piezoelectric materials can make substantial contributions to resolve the overall energy crisis by providing a renewable energy solution. With the present increase in the number of microscale devices, piezoelectric power generation can provide an appropriate alternative to conventional power sources for low powered electronic devices. In this study, Flexible PVDF, PVDF-MoS 2 , and PVDF-rGO-MoS 2 thin films were prepared by polymer solution casting method and their piezoelectric properties are explored. The structural and morphological characteristics of the synthesized materials and thin films were examined using XRD, FTIR, and PFM techniques. The fabricated flexible film is encapsulated with an insulating layer so that when we tap the device, the electrodes are not affected. The flexible thin film of PVDF-rGO-MoS 2 has significantly improved generated voltage which is ~5 times higher than the flexible film of PVDF and ~2 times higher than PVDF-MoS 2 flexible film. The mechanism involved in the improved piezoresponse of the flexible thin film was also proposed. [ABSTRACT FROM AUTHOR]

• 3D hierarchical Bi 2 S 3 nanoflowers synthesized by hydrothermal route. • Implementation of a facile and low cost two-step procedure to synthesize PANI/Bi 2 S 3 nanocomposite at RT. • Rational design and fabrication of 3D hierarchical PANI/Bi 2 S 3 photoanode for visible light induced PEC water splitting. • Demonstration of ~5 fold increased photocurrent density by PANI/Bi 2 S 3 than that of Bi 2 S 3 photoanode. • Enhanced PEC performance achieved due to staggered Type-II heterojunction and faster charge transport. ga1 The fabrication of the semiconductor photoanode with good chemical stability, sufficient light harvesting ability, and fast charge carrier separation and transportation capability is crucial for efficient photoelectrochemical (PEC) water splitting. Herein, we designed the nanocomposite based photoelectrode which is integrated by hydrothermally grown 3D hierarchical nanoflowers (NFs) of bismuth sulfide (Bi 2 S 3) and conducting polymer polyaniline (PANI). The as-fabricated PANI/Bi 2 S 3 photoanode has demonstrated much enhanced photocurrent density (~6.95 mA/cm2 at 0.8 V vs. NHE), which is ~5 fold higher in comparison to Bi 2 S 3 photoanode (~1.30 mA/cm2 at 0.8 V vs. NHE). Also, the PANI/Bi 2 S 3 photoanode has exhibited profoundly increased charge separation and injection efficiency of ~78.31% and ~90.18%, respectively. Furthermore, ~3 fold increased incident photon-to-current conversion efficiency (IPCE) value is achieved by PANI/Bi 2 S 3 as compared to the Bi 2 S 3 photoanode. The rational design of hierarchical semiconductor heterojunction, improved visible light absorption, efficient separation of photogenerated charge carriers, and faster charge transport properties altogether account for the enhanced PEC performance of the fabricated PANI/Bi 2 S 3 photoanode. A possible schematic model for the significantly enhanced activity of the PANI/Bi 2 S 3 photoanode for solar light induced PEC water splitting has also been explicated. These findings would provide new opportunities for understanding, exploration, and advancement of different other novel 3D hierarchical nanostructures based systems in the area of energy conversion, harvesting, and storage in the future. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS 2), a transition metal dichalcogenides (TMDs) is a potential candidate for thermoelectric due to its inherent low thermal conductivity. However, its low electrical conductivity confines its practical usage. In this paper, we have synthesized nanocomposite of MoS 2 with reduced graphene oxide (RGO) and demonstrated a ∼5920% increase in the thermoelectric figure of merit of MoS 2 after formation of MoS 2 -RGO nanocomposite. This ultra-high enhanced thermoelectric figure of merit is due to significantly enhanced electrical conductivity, increased Seebeck effect and simultaneous reduction of thermal conductivity of MoS 2 in the MoS 2 -RGO nanocomposite. Presence of RGO in the matrix of MoS 2 in MoS 2 -RGO nanocomposite provides conducting path, reduces interface barrier height and also provides enhanced scattering of phonons. • MoS 2 -RGO nanocomposite has been synthesized by reflux method. • Structural characterizations of MoS 2 -RGO nanocomposite have been done. • MoS 2 is a potential candidate for thermoelectric Application. [ABSTRACT FROM AUTHOR]

• No change in the orthorhombic crystal structure of YBCO in all nanocomposite samples. • A decrease in T c from 92 K to 90.5 K for 2 wt% concentration of NaNbO 3 in nanocomposite sample. • Significant enhancement in critical current density and pinning force of the order of ~2.5 times for 0.5 wt% added composite sample in comparison to pure YBCO. In this work, sodium niobate (NaNbO 3) nanorods (NR) – YBCO superconductor composites with different wt% (0–2%) of NaNbO 3 were prepared via a two-step process of hydrothermal and solid-state reaction, and its structural, electrical, and magnetic characterizations were carried out. XRD studies revealed that the orthorhombicity of YBCO is preserved in all nanocomposite samples. The superconducting transition temperature decreases from 92 K to 90.5 K when the addition of NaNbO 3 was increased to 2 wt%. Magnetization studies revealed a significant increase of critical current (J c) and pinning force (F p) in the NaNbO 3 (NR) added YBCO sample which has been attributed to the creation of artificial pinning centers due to the presence of NaNbO 3 NR. For the 0.5 wt% nanorods added sample, the enhancement in J c and F p was maximum. Temperature and field dependence of J c were carried out to probe the nature of pinning in the nanocomposite superconductors. [ABSTRACT FROM AUTHOR]

Abstract: Temperature dependence of resistivity of double layered manganite La2−2x Ca1+2x Mn2O7 (‘x’=0.1, 0.2, 0.3 and 0.4) has been investigated in the temperature range of 4.2–50K. An upturn in the resistivity was observed for all the compositions. The increase of resistivity with the decrease in temperature was found to be due to combined effect of weak localization and electron–electron scattering. The observed minimum in the resistivity is attributed to a competition between weak localization, electron–electron scattering and electron–phonon scattering. [Copyright &y& Elsevier]