Among various metal chalcogenides, metal oxides and phases of copper sulfide, copper(II) sulfide (covellite, CuS) nanostructures have enjoyed special attentiveness from researchers and scientists across the world owing to their complicated structure, peculiar composition and valency, attractive and panoramic morphologies, optical and electrical conductivity, less toxicity, and biocompatibility that can be exploited in advanced and technological applications. This review paper presents a brief idea about crystal structure, composition, and various chemical methods. The mechanism and effect of reaction parameters on the evolution of versatile and attractive morphologies have been described. Physical properties of CuS and its hybrid nanostructures, such as morphology and optical, mechanical, electrical, thermal, and thermoelectrical properties, have been carefully reviewed. A concise account of CuS and its hybrid nanostructures' diverse applications in emerging and recent applications such as energy storage devices (lithium-ion batteries, supercapacitance), sensors, field emission, photovoltaic cells, organic pollutant removal, electromagnetic wave absorption, and emerging biomedical field (drug delivery, photothermal ablation, deoxyribonucleic acid detection, anti-microbial and theranostic) has also been elucidated. Finally, the prospects, scope, and challenges of CuS nanostructures have been discussed precisely.

In this study, cupric oxide (CuO) nanoparticles (NPs) were synthesized using copper chloride and different concentrations of sodium hydroxide in an aqueous medium without the use of a surfactant or template. The crystal structure, purity, crystallite size, intrinsic strain, stress, and elastic energy of the as-synthesized samples were all determined using x-ray diffraction (XRD). CuO nanoparticles were confirmed to have a monoclinic structure through XRD analysis. From the XRD peak broadening analysis, the crystallite size and intrinsic strain were investigated using the Williamson–Hall plot (WHP), size–strain plot (SSP), and Halder–Wagner (HW) method. To determine physical and micro-structural parameters such as strain, stress, and energy density, the WHP used three different models: the uniform deformation model (UDM), the uniform stress deformation model (USDM), and uniform deformation energy density model (UDEDM). Field-emission scanning electron microscopy (FE-SEM) micrographs revealed leaf-like, flower-like, and network-like morphologies. At room temperature, the optical properties of the CuO NPs were investigated using ultraviolet-visible (UV–Vis) and photoluminescence (PL) spectroscopy. Using Tauc's plot, the estimated optical energy bandgap ( E g ) was 3.70–3.80 eV. CuO nano-leaves had a strong green emission peak at 504 nm and a less intense emission peak at 757 nm.

Objective: In the present study, cupric sulfide (CuS) nanoparticles (NPs) were synthesized in deionized (DIW) water using an eco-benign, simple, and cost-effective chemical route that requires no surfactant or template. Methods: Polypyrrole/cupric sulfide (PPy/CuS) hybrid nanocomposite (HNC) was synthesized using an in-situ chemical oxidative polymerization method in the presence of obtained CuS NPs. The X-ray diffraction (XRD) analysis confirmed the hexagonal structure of CuS, whose crystalline nature was preserved in the HNC. For CuS NPs and PPy/CuS HNC, elastic properties, such as intrinsic microstrain, internal stress, dislocation density, strain energy density, stacking faults, and intercrystalline separation, were used to analyze the crystal imperfections and distortions. Results: Field emission scanning electron spectroscopy (FESEM) micrographs revealed that CuS NPs and PPy/CuS HNC have particulate and globular morphology, respectively. The values of the average intrinsic strain, dislocation density, internal stresses, and strain energy density of PPy/CuS HNC were estimated to be ~2 × 10-3, ~8.8166 × 1015 m-2, 164.263 MPa, and 127.278 KJ m−3, respectively, which were observed to be higher than those of CuS NPs. Conclusion: The DC electrical conductivity of as-synthesized samples was measured at room temperature in pelletized form, using the standard four-probe method, and conductivity values were estimated to be ~480 Scm-1 and ~4 Scm-1 for CuS NPs and PPy/CuS HNC, respectively.

In this study, polypyrrole cuprous iodide (PPy-CuI) hybrid nanocomposites were synthesized in an aqueous medium via an in-situ chemical oxidation route with ammonium persulphate as an oxidizing agent to report the microstructural, morphological, and electrical properties of as-synthesized specimens. By using an in-situ oxidative polymerization method, sonochemically synthesized gamma-CuI nanocrystals were mixed with a PPy matrix in varying weight percentages (10-40 %). The purity, crystallinity and structure of hybrid nanocomposites were determined using X-ray diffractometry. The average crystallite size of hybrid nanocomposites was calculated using the DebyeScherrer, Williamson-Hall and Size-Strain plot methods. All specimens' intrinsic strain was estimated using the Williamson-Hall plot and the Size-Strain plot methods. The field emission scanning microscopy revealed that the surface morphology changed from granular to overgrown clusters as the weight percent of CuI nanocrystals is increased from 10 to 40 % in PPy-CuI hybrid nanocomposites. The Fourier transform infrared spectroscopy indicates the formation of PPy and successful insertion of gamma-CuI nanocrystals into the PPy matrix. The room temperature dc electrical conductivity is found to decrease from 6.3 x 10(-2) Scm(-1) to 1.70 x 10(-3)Scm(-1)as the wt% of.-CuI nanocrystals increases from 10 to 40 % in hybrid nanocomposites. Furthermore, the increasing trend of dc conductivity with temperature is due to all samples' semiconducting nature. In the temperature range of 200-300 K, the measured experimental data followed the Arrhenius and Mott's 3d variable range hopping (VRH) model. The values of average activation energy, average hopping energy, density of states at Fermi level, average hopping distance and Mott's characteristic temperature of PPy-CuI (40 %) hybrid nanocomposites at 300 K were estimated to be similar to 60 meV, similar to 29 meV, 6.36 x 10(22) cm(-3)eV(-1), 5.06 angstrom and 1901 K, respectively.

Polypyrrole-based hybrid nanocomposites have drawn much attentiveness of the researchers and scientists owing to their superior and much improved physical, chemical and biomedical properties. This review article outlines the important synthesis strategies, properties and conduction mechanism of polypyrrole-based hybrid nanocomposites. Moreover, an exhaustive account of their diverse applications in energy storage devices, electronic devices, sensors, electromagnetic interference shielding and microwave absorption, actuators, protective or anti-corrosion coatings, catalyzed photo-degradation of dyes, removal of other environmental pollutants and biomedical field has been overviewed. At last, future prospects and challenges of polypyrrole-based hybrid nanocomposites have been highlighted precisely.

In this study, we reported facile sonochemical synthesis of CuS nanoparticles by using CuCl2 and Na2S in aqueous medium without using any organic solvent and surfactant. Structural characterization of synthesized product using X-ray diffraction study revealed the formation of hexagonal structure of CuS in covellite phase. Crystallite size of ~13 and ~11 nm were determined using Debye–Scherrer and Williamson–Hall methods, respectively. Field emission scanning electron microscopy micrographs revealed the particulate morphology of CuS nanostructures. The optical properties of CuS nanoparticles were investigated by ultra violet and visible (UV-Vis), photoluminescence (PL), and Fourier transform infrared spectroscopy. The band gap was calculated by Tauc’s relation and found to be 3 eV. The PL spectrum showed a strong green emission at wavelength 505 nm. The electrical conductivity of CuS nanoparticles was found to be in semiconducting range, i.e. 550 S/cm. Impedance analysis of CuS nanoparticles revealed 7.55 MHz as the resonant frequency.

Semiconducting cuprous iodide (CuI) nanocrystals have been synthesized by the one-pot sonochemical method at room temperature. The synthesis was performed in aqueous medium using ascorbic acid, polyvinyl pyrrolidone, p-toluene sulfonic acid and docusate sodium as surfactants. X-ray diffraction (XRD) study of resulting material reveals the crystalline nature, cubic zinc blende lattice structure and gamma phase of CuI nanocrystals. Scherrer method, Williamson-Hall plot and Size-Strain plot method have been used to investigate the particle size and intrinsic strain values from the XRD analysis. Field emission scanning electron microscopy (FESEM) revealed the morphology and different shapes (truncated tetrahedron, irregular, hexagonal & clustered) of CuI nanocrystals synthesized using different surfactants. In the PL spectrum of gamma-CuI nanoparticles strong near band-edge emission was observed at about 423 nm. A slight red-shift in near band edge emission was observed due to the presence of surfactants. Enhanced electrical conductivity values (1.96 S/cm-9.19 S/cm) were obtained due to the presence of surfactants for gamma-CuI nanocrystals. These properties of CuI nanocrystals makes them a suitable material for the design and development of optoelectronic devices.

Hybrid nanocomposites (HNCs) of polypyrrole (PPy) and CuS were synthesized by an in situ chemical polymerization method. The HNCs were prepared by varying the CuS nanoparticles weight percentage (10–40%) in PPy matrix. The XRD and FESEM characterization indicated the uniform distribution of CuS nanoparticles in PPy matrix. The XRD pattern revealed the presence of hexagonal CuS peaks overlapped with amorphous PPy pattern. Williamson Hall method was employed to estimate intrinsic strain in HNCs. FTIR spectrum revealed the shifting of 1025 cm−1 peak toward higher wavenumber, indicating insertion of CuS nanoparticles in PPy. The room temperature electrical conductivity of PPy is found to be increased from 1.15 × 10−1 to 3.70 S/cm as the content of CuS nanoparticles increases up to 40 wt% in HNCs. To explore the charge transport mechanism in HNCs,the conductivity was measured in the temperature range of 300–15 K. The measured conductivity data was analyzed with the help of Arrhenius model and 3d Mott’s variable range hopping (VRH) model in the temperature range of 35–300 K. The approximate values of Mott’s parameters at 300 K such as the density of states at Fermi level, average hopping distance and average hopping energy of HNCs were estimated as ~ 4×1024 cm−3eV−1, ~ 1.7 Å and ~ 10 meV respectively.

Gamma-ray mass attenuation coefficients have been measured experimentally and calculated theoretically for PbO–B2O3 and Bi2O3–PbO–B2O3 glass systems using narrow beam transmission method. These values have been used to calculate half value layer (HVL) parameter. These parameters have also been calculated theoretically for some standard radiation shielding concretes at same energies. Effect of replacing lead by bismuth has been analyzed in terms of density, molar volume and mass attenuation coefficient.