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We report the hydrogen-sensing response on low-cost-solution-derived ZnO nanorods (NRs) on a glass substrate, integrated with aluminum as interdigitated electrodes (IDEs). The hydrothermally grown ZnO NRs on ZnO seed-layer-glass substrates are vertically aligned and highly textured along the

Implementation of stealth features on advanced airborne platforms (aircrafts, unmanned air vehicles, missiles, etc.) has become a compulsion for each country, for denial/delay detection of these objects from enemy radars, during tactical missions. Apart from the shaping of the airframe, implementation of microwave-absorbing materials (MAMs) on identified locations of airborne vehicles is the only viable solution to reduce their radar cross-section (RCS) and eventually attain stealth capabilities. Numerous dielectric and magnetic class materials have been developed over the last few decades to fulfil the requirement for RCS reduction against various radars operating in different frequency ranges. In this review, a detailed representation of almost the entire range of materials used as MAMs has been provided along with their possible microwave (MW) loss mechanism to fill the gap that existed for a systematic insight on MAMs till now. The current limitations and future aspects are also discussed for the development of future stealth materials.

The relevant fundamental properties of Janus WSSe monolayers to photocatalytic water-splitting performance are presented here and investigated using density functional theory. The Janus WSSe monolayer with a direct band gap of 1.75 eV is subjected to biaxial strain, and related optoelectronic properties are investigated. The effect of strain is reflected in band gap change from direct to indirect. Hydrogen evolution reaction (HER) is active all over, whereas oxygen evolution reaction (OER) is active only at 4% and 6% compressive strains. The red- and blue-shifts under tensile and compressive strains, respectively, substantiate possible control over exciton-phonon interaction making it suitable for the water-splitting application. Upon being irradiated by sunlight with sufficient energy, the biaxially strained Janus WSSe monolayer complying with HER/OER requirement produces hydrogen gas along with oxygen as a secondary product.

We investigated a single heterojunction solar cell with stannite phase Cu2HgSnS4 as a new potential absorber material using the hybrid density functional theory for materials parameter and macroscopic device simulation studies for the photovoltaic response. The lattice constants are optimized using PBEsol and GGA exchange–correlation approach with mBJ parameterization and considering spin–orbit coupling effect on heavy element Hg, while strong correlation of Cu and Hg 3d electrons are taken into account by Hubbard parameter U = 0.52 Ry. The computed bandgap is ~1.33 eV. The effective mass of electrons and holes in the respective band edges (electron in conduction band and the hole in the valence band) is 0.25 m0 and 0.91 m0, respectively. Further, the computed materials optoelectronic parameters are used to optimize the device performance by introducing a variation in minority carrier lifetime, defect concentration in Cu2HgSnS4 absorber, Cu2HgSnS4/CdS interface, and the absorber thickness to achieve a realistic photovoltaic response. The optimal conversion efficiency is 11.6% after taking more realistic parameters in the considered single-junction solar cell. However, the maximum photovoltaic response >17% can be achieved by controlling absorber and interface defects together with optimal carrier concentration.

The present paper aims at the material design for wind turbine blade that can sustain different environmental conditions. It is difficult to keep regular maintenance of blade; we need to design a material that can repair the damage by its own. The present work is an attempt to study the effect of moisture, temperature and saline medium on glass fiber-reinforced polymer (GFRP) having Cloisite 30B (nanoclay) as reinforcement in epoxy polymer matrix. The changes in the physical and mechanical properties of the composite material under accelerated condition have been studied. The concept of self-healing is a vital tool to encounter the damage by itself. We have used DCPD (dicyclopentadiene)-contained microcapsules as a healing agent. These microcapsules have shown a great decrease in the rate of degradation of blade material. Wind turbine blades are mainly made up of FRP composites, and these composites have tendency to absorb moisture. It has been observed that water absorption can affect the mechanical performance as well as reduce the durability of turbine blade. To encounter this effect, nanoclay as filler has been used in GFRP composites. It has been noticed that degradation reduces to high extent. The percentage reduction in strength is more in saline water than in normal tap water. Epoxy samples show more degradation in saline medium (39–46%) at 40 °C as compared to plain water medium (29–41%) at the same temperature.

We report the enhancement of microwave absorption properties in BaTiO3 ceramics induced by exposing under high energy gamma radiation at 5 kGy, 10 kGy and 15 kGy, gamma-ray doses in a properly shielded Co60 γ-radiation chamber. The tetragonality ratio (c/a) decreases with increasing gamma dose on powder samples together with the reduction of grain size from ~2 μm to ~0.5 μm. Further, the irradiated BaTiO3 powder based ceramic tiles are fabricated and electromagnetic (EM) measurements suggest increase in imaginary permittivity and loss tangent values (tanδe) at resonance frequency of ~8.8 GHz. Reflection loss (RL) plots of BT tiles showed enhancement in microwave loss at higher gamma radiation doses. As per the customized requirements, two type of extremely thin ceramic tiles are obtained viz. Resonating (RL> 40 dB at 9.6 GHz) and wide-band (RL> 8 dB over entire X-band) for their possible use for MW attenuation on different objects/platforms.

Transition metal dichalcogenides based materials exhibit promising optoelectronic properties for solar cell application. We considered the heterostructure single junction solar cell with bulk W(S/S...

The present work investigates analytically and experimentally the multimodal performance analysis of piezoelectric (PZT-5A) based generic nanogenerators. The present nanogenerators consider both uni-morph and bimorph with offset-proof mass subjected to sinusoidal base excitation. The finite element-based multi-mode electromechanical coupled dynamics governing equations are derived to formulate the analytical expressions of uni-morph, and bimorph nano-harvesters for frequency responses function of output voltage, current, and power, respectively. The impact of base excitation, load resistance, thickness, length, and mass of offset-proof mass on the output voltage and harvested energy is investigated by considering multi-mode vibration bodies. PZT-5A is evenly distributed over the substructure for the single voltage output. Interestingly, we noticed that a uni-morph cantilever with offset-proof mass is the best among all the investigated configurations, showing the maximum power at different load conditions. Analytical solutions are in good agreement with nearly no error for the first few vibration modes as compared to what was obtained using numerical simulation. The experimental realization for a single mode of vibration has been explored, and results showed that the fundamental mode swings very similar behaviors in voltage and power output, mostly in pre-and post-resonance conditions as compared to analytical results, and the difference between these two results is about nearly 5%. Thus, the present work depicts an effectual correlation between analytical development, numerical results using COMSOL 2D, and experimental realization for analyzing energy harvesting devices. These results may be helpful for the experimentalists to design efficient nanogenerators.

We report the preparation of the ZnO-6LiF composite with a polystyrene (PS) polymer as a host using the solution mixing process. 6LiF acts as a converter material that absorbs a thermal neutron and produces alpha particles, which excites ZnO micro-particles, resulting in UV–vis photons’ emission. The free-standing ZnO-6LiF/PS composite film is coupled to a photomultiplier tube (PMT). 241Am-Be (1Ci) is used as the neutron radiation source for measuring the response. We compared the response of the composite scintillator consisting of (i) natural LiF and (ii) 95% 6Li enriched LiF (6LiF). The increased pulse heights are recorded for 95% 6Li enriched, i.e., 6LiF converter. It confirms the generation of alpha particles after the absorption of a neutron in 6LiF. Furthermore, ZnO and 6LiF are considered in different weight proportions, 2:1, 1:1, and 1:2, keeping the total loading 50% (w/w) of polystyrene. The ZnO:6LiF (1:1)/PS composite showed higher scintillation pulse heights than the other two composites. Repetitive measurements are performed for the ZnO-6LiF(1:1)/PS composite, showing ±5% variation in respective responses. We also investigated the impact of different counting times and source-to-detector responses for the ZnO-6LiF(1:1)/PS composite. The response increases linearly with neutron dose, exhibiting a sensitivity of ∼203 counts/ μSv. Neutron measurement counts at different source-to-detector distances have a similar trend as that of neutron dose measured by using a neutron dosimeter. Thus, this work demonstrated the potential of the ZnO-6LiF/PS composite, coupled to PMT for detecting thermal neutron radiation.

We report the origin of capacity fading in Li2FeSiO4 cathode material, while addressing the challenges associated with the synthesis of phase-pure Li2FeSiO4 positive electrode materials in bulk and nanostructured geometries. The process has been optimized to remove iron oxide (Fe2O3) impurities and for effective carbon coating on a Li2FeSiO4 nanostructured core using a carbon source precursor during the synthesis process. X-ray diffraction measurements confirm the phase purity and nanocrystalline nature of synthesized materials. UV–visible spectroscopic measurements are carried out to understand the electronic/optical characteristics, and their correlation with materials’ electrochemical performance is investigated. The impact of iron charge state in an FeO4 tetrahedra configuration is correlated to the electrochemical performance together with the lithium-ion transporting states. The Jahn–Teller active FeO4 tetrahedra may show structural distortion in the sub-lattice of Li2FeSiO4 with different charge states and may be the main source of capacity fading in Li2FeSiO4 cathode material from the first cycle onwards.

Adsorption characteristics of carbon nanotubes (CNTs) intercalated with nickel is a subject of growing experimental and theoretical interest. In this manuscript adsorption of hydrogen gas on the surface of nickel intercalated multiwall carbon nanotubes (MWNTs) has been studied. It is expected that metal catalysts like nickel can have possible pattern of atoms and molecules on the surface of MWNTs with varying parameters like diameters, concentration of nickel & MWNTs for sorption kinematics. Distribution and strong interaction of Ni with the MWNTs could support. Thus, adsorption capacity of the hydrogen via the spillover effect is expected. Ni doped MWNTs composites have been examined by using X-ray diffraction (XRD), Fourier Transform (FT-IR) infrared spectroscopy , Sorption kinetics (Sievert’s spectrometer), and Scanning Electron Microscopy (SEM).

X-ray diffraction (XRD) techniques are powerful, non-destructive characterization tool with minimal sample preparation. XRD provides the first information about the materials phases, crystalline structure, average crystallite size, micro and macro strain, orientation parameter, texture coefficient, degree of crystallinity, crystal defects etc. XRD analysis provides information about the bulk, polycrystalline thin films, and multilayer structures, which is very important in various scientific and material engineering fields. This review discusses the diffraction related phenomena/principles such as powder X-ray diffraction, and thin-film/grazing incidence X-ray diffraction (GIXRD) comprehensively for thin film samples which are used frequently in various branches of science and technology. The review also covers few case studies on polycrystalline thin-film samples related to phase analysis, preferred orientation parameter (texture coefficient) analysis, stress evaluation in thin films and multilayer, multiphase content identification, bifurcation of multiphase on multilayer samples, depth profiling in thin-film/ multilayer structures, the impact of doping effect on structural properties of thin films etc., comprehensively using GIXRD/XRD.

Molybdenum Trioxide (MoO3) films are grown on Si(100) substrates by reactive RF magnetron sputtering in plasma containing a mixture of Argon and Oxygen, using a pure Molybdenum target. In this paper, we report the deposition of (MoO3) films on Si(100) substrates under varying gas flow (O2 + Ar gas) (20 sccm to 30 sccm with the duration of deposition~ 1hr) by RF reactive magnetron sputtering at room temperature. To get crystalline MoO3 films annealing in O2 environment at 500 °C for 4 h is done. Phase formation and orientation of the film is characterized by Glancing incidence X-ray diffraction (GIXRD). The identification of the orthorhombic MoO3 phase is investigated by XRD and Raman spectroscopy. Raman lines at 819 cm-1 and 995 cm-1 are due to the (A1g, B1g) symmetric stretching (Mo-O–Mo) bond and asymmetric stretching band (Mo=O) respectively. Surface morphology and cross-sectional image of the deposited thin films were investigated by FE-SEM image. UV-Visible reflectance and cross-sectional FE-SEM image confirm the thickness of the MoO3 films with oxygen-rich and oxygen deficient phase formation occur. Reverse leakage current density of 20 sccm 1hr sample is low (1×10-6 mA/cm2) as compared to 30 sccm 1hr sample (1×10-3 mA/cm2). The higher leakage is due to crack formation during the ex-situ annealing of MoO3 films. This MoO3 films can be used in Gas sensing and switching devices.

Quantum Dot Sensitized Solar Cells are considered as the potential third generation solar cells due to their suitable optoelectronic properties for photovoltaic response. The possibility of size and composition tunability makes quantum dots as relevant absorber materials to match the wider solar spectrum more efficiently. In conjunction, the possibility of multiple electron-hole pair generations at the cost of single photon i.e. multiple carrier generation is showing potential to overcome the theoretical single junction power conversion efficiency limitations. Quantum dot sensitized solar cells are showing power conversion efficiencies up to 12%, very close to its counterpart dye sensitized solar cells. However, QDSSCs efficiencies are still lagging behind the conventional solid state single junction solar cells. In this review, we will discuss the initial evolution of quantum dot sensitized solar cells with their microscopic working principles. The review will also address development of key building blocks and factors such as various interfaces in QDSSCs, carrier transport and recombination across different interfaces, affecting the power conversion efficiency. Further, fundamental concepts of carrier multiplication and possible theoretical models for multiple exciton generation are discussed towards their impact on the power conversion efficiencies of quantum dot sensitized solar cells.

A chemiresistive, 1T-TiS2 nanosheet (TNS) based gas sensor has been developed, and its ultrahigh sensitivity toward hydrogen sulfide (H2S) and oxygen (O2) gas at room temperature has been experimen...

We demonstrated ultrahigh sensitivity with excellent recovery time for H2S, NH3, NO2, and NO molecules on the sulfur and selenium surfaces of Janus WSSe monolayers using density functional theory. The selenium surface of the WSSe monolayer showed strong adsorption in comparison to the sulfur surface. The respective adsorption energies for H2S, NH3, NO2 and NO molecules are -0.193 eV, -0.220 eV, -0.276 eV, and -0.189 eV. These values are higher than the experimentally reported values for ultrahigh sensitivity gas sensors based on MoS2, MoSe2, WS2, and WSe2 monolayers. The computed adsorption energy and recovery time suggest that the desorption of gas molecules can be achieved easily in the WSSe monolayer. Further, the probable vacancy defects SV, SeV, and (S/Se)V and antisite defects SSe, and SeS are considered to understand their impact on the adsorption properties with respect to the pristine WSSe monolayer. We observed that the defect-including WSSe monolayers showed enhanced adsorption energy with fast recovery, which makes the Janus WSSe monolayer an excellent material for nanoscale gas sensors with ultrahigh sensitivity and excellent recovery time.

Ruddlesden-Popper (RP) phase metal halide organo perovskites are being extensively studied due to their quasi-two dimensional (2D) nature which makes them an excellent material for several optoelectronic device applications such as solar cells, photo-detectors, light emitting diodes (LEDs), lasers etc. While most of reports show use of linear carbon chain based organic moiety, such as n-Butylamine, as organic spacer in RP perovskite crystal structure, here we report a new series of quasi 2D perovskites with a ring type cyclic carbon group as organic spacer forming RP perovskite of type (CH)