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Fully solid-state lithium-ion cells have the benefits of excellent safety, remarkable electrochemical stability, and extended cycle life. They are categorized as prospective candidates for new-generation energy storage devices capable of safe and stable operation for relatively long periods. In whole solid-state Li-ion cells, polymer-based solid electrolyte membranes (SEMs) are expected to serve as both the solid electrolyte and the partition material. Remarkably high ionic conductivity and efficient ion diffusion can be achieved in SEMs by incorporating inorganic filler materials. In the present work, solid electrolyte membranes are developed by a simple solution cast method. The addition of Al2O3 nanoparticles is found to enhance the ionic conductivity of SE membranes to 1.25 × 10−4 S cm−1 for optimum concentrations of lithium salt and filler material. These SE membranes show relatively high electrochemical stability window up to 4.75 V. Transparent and freestanding SE membranes developed using PEO-PVDF-LiNO3-Al2O3 have excellent thermal stability, ideal ion transport number, and good electrochemical properties, suitable for applications in solid-state lithium-ion cells. Assembled LiFePO4-MWCNT//SEM//Li metal half-cells are found to deliver an initial discharge capacity of 128 mAh g−1 at 0.1 C and an initial Coulombic efficiency of 98%. [ABSTRACT FROM AUTHOR]

Design and development of promising electrode materials for supercapacitors has been a vital topic of current research focus. Here, we report the supercapacitive performance of the strontium titanate–graphene quantum dot–polyaniline heterohybrid. The synthesis strategy involves a sequential sol–gel synthesis of strontium titanate, followed by hydrothermal aided interface formation with graphene quantum dots (GQD) and polyaniline (PANI) deposition by chemical oxidative polymerization. A high specific capacitance of 2134 F g−1 could be observed in 1 M H2SO4 electrolyte at a current density of 1 A g−1. The Ragone plot for the symmetric cell reveals an energy density of 16.2 W h kg−1 at a power density of 4533.7 W kg−1. The 97.7% retention of specific capacitance demonstrated at higher current densities ensures high rate capability. Further, the device demonstrated a capacitance retention of 80% at 10 A g−1 after 10000 galvanostatic charge–discharge cycles. Low interfacial charge transfer resistance as evidenced by impedance spectroscopy analysis and high performance could be attributed to the synergistic interaction at the interface. [ABSTRACT FROM AUTHOR]

Memory technologies are essential for transferring and preserving data. As the digital age progressed, memory device size, speed and efficiency were tuned to address the new demands. Resistive random access memory (RRAM) devices are promising candidates for future memory applications and have many advantages, such as scaling, speed, and endurance over conventional flash memory. In this work, bilayer metal oxide (MoOx/ZnO) devices are fabricated with Ag and ITO as top and bottom electrodes and their resistive switching characteristics are investigated for non-volatile memory applications. I–V characteristics of the device are analysed for the characteristic pinched hysteresis loop where bipolar switching has been observed with set voltage at 1.1 V and reset voltage at - 0.8 V. The field-dependent migration of oxygen vacancies in metal oxide layers accounts for the bipolar switching mechanism. The conduction mechanism for ITO/ZnO/MoOx/Ag device is studied, revealing ohmic conduction in the low voltage region while space charge limited conduction dominates in the high voltage region. Furthermore, the fabricated device shows excellent retention. Conclusively, this study suggests that the device switches at comparatively lower voltages and has remarkable data retention properties with the addition of MoOx layer over ZnO layer. Since the device shows excellent endurance and data retention properties, the fabricated device can be a good candidate for non-volatile memory applications such as RRAM and neuromorphic computing. [ABSTRACT FROM AUTHOR]

Artificial synapses are the basic building block of artificial neural networks capable of neuromorphic computing, which might overtake conventional digital computing in areas like artificial intelligence, deep learning, and in‐memory computation. Neuromorphic computing with artificial synapses opens a new window for fast in‐memory computing and image processing. In this paper, an MoOx‐based artificial synapse that mimics almost all characteristics of bio‐synapses is demonstrated. The fabricated device shows excellent synaptic properties such as potentiation, depression, forgetting, paired‐pulse facilitation, and spike‐timing‐dependent plasticity. The mechanism behind all the observed characteristics has been well explained. A lateral‐type device is also designed and tested in order to confirm the conductance change during the application of electrical pulses. Energy‐dispersive X‐ray analysis and Raman analysis reveal that the switching mechanism is primarily due to the formation and rupture of conducting filaments composed of Magnéli phases of MoOx. Since the fabricated ITO/MoOx/Ag artificial synapse exhibits excellent synaptic characteristics and the mechanism is thoroughly explored, this study will contribute to the fabrication of neural networks and future neuromorphic computing. [ABSTRACT FROM AUTHOR]

In this work, a systematic study of surface-enhanced Raman scattering (SERS) on TiO2/Ag hybrid structure is presented. TiO2 nanofibers are synthesized by the electrospinning method and are decorated with silver nanoparticles following a simple chemical route to develop TiO2/Ag hybrid structure. First, SERS of rhodamine 6G is measured using the TiO2/Ag hybrid structure and optimized the growth conditions. The fabricated SERS substrate could detect rhodamine 6G molecules with a detection limit of 10−14 M. The enhancement factor of the order of 109 is observed owing to the synergetic effect of electromagnetic enhancement and chemical enhancement. The substrate is found to be reusable owing to the photocatalytic activity of TiO2. The multi-analyte detection capability of SERS substrate is also studied. Also, the feasibility of using the fabricated substrates for the trace level detection of insecticide imidacloprid is demonstrated. [ABSTRACT FROM AUTHOR]

Epitaxial (111) Ba0.5Sr0.5TiO3 (BST) thin films have been grown by pulsed laser deposition on (0001) Al2O3 substrate with ZnO as buffer layer. The x-ray ω-2θ, Φ-scan and reciprocal space mapping indicate epitaxial nature of BST thin films. The domain matched epitaxial growth of BST thin films over ZnO buffer layer was confirmed using Fourier filtered high resolution transmission electron microscope images of the film-buffer interface. The incorporation of ZnO buffer layer effectively suppressed the lattice mismatch and promoted domain matched epitaxial growth of BST thin films. Coplanar inter digital capacitors fabricated on epitaxial (111) BST thin films show significantly improved tunable performance over polycrystalline thin films. [ABSTRACT FROM AUTHOR]

Low-cost, highly efficient, and stable solar cells demand low-temperature processing, less stringent criteria on materials, and possibility of dynamic recovery from long-term degradation–a combination of features unachievable from the perspectives of current c-Si technology. To this end, here we propose a novel solar cell architecture with an additional control gate. Our simulation results indicate that the proposed device can achieve excellent efficiency even if the back-surface passivation is suboptimal–thus allowing exploration of a wide variety of materials and low-temperature fabrication processes. Importantly, such solar cells can dynamically offset efficiency loss due to elevated temperature and interface degradation associated with long-term field operation and hence could be of broad interest to the photovoltaics (PV) community. [ABSTRACT FROM AUTHOR]

Zinc indium tin oxide (ZITO) transparent conductive oxide layers were deposited via radio frequency (RF) magnetron co-sputtering at room temperature. A series of samples with gradually varying zinc content was investigated. The samples were characterized with x-ray and ultraviolet photoemission spectroscopy (XPS, UPS) to determine the electronic structure of the surface. Valence and conduction bands maxima (VBM, CBM), and work function were determined. The experiments indicate that increasing Zn content results in films with a higher defect rate at the surface leading to the formation of a degenerately doped surface layer if the Zn content surpasses ∼50%. Furthermore, the experiments demonstrate that ZITO is susceptible to ultraviolet light induced work function reduction, similar to what was earlier observed on ITO and TiO2 films. [ABSTRACT FROM AUTHOR]