Lighting-environment-adjustable block-type 3D indoor PV for wireless sensor communication.

Demand is increasing for photovoltaics (PVs) as a result of the development of the Internet of Things and edge computing technologies. As the lighting environment is different for the applications, thus, PVs must be adjustable to various light environments in which systems are installed. PVs should therefore be capable of easily changing their morphology without damaging the cells.

Small area high voltage photovoltaic module for high tolerance to partial shading.

The urban application of photovoltaics is necessary to achieve carbon-free electricity production. However, the serial connections within modules cause problems under partial shading conditions, which is inevitable in urban applications. Therefore, a partial shading-tolerance photovoltaic module is needed.

Kirigami-inspired automatically self-inclining bifacial solar cell arrays to enhance energy yield under both sunny and cloudy conditions.

The application of photovoltaics (PVs) is expanding in various locations ranging from industrial facilities to residential housing. The emphasized concept in the PVs field is shifting from "watt-per-cost" to "energy-yield-per-watt." To attain a high energy yield, fixed modules are not well suited to capture both direct and omnidirectional light.

Automated shape-transformable self-solar-tracking tessellated crystalline Si solar cells using in-situ shape-memory-alloy actuation.

Photovoltaic energy systems in urban situations need to achieve both high electricity production and high capacity in restricted installation areas. To maximize power output, solar-tracking systems tilt solar arrays to track the sun's position, and typically flat modules are used to maximize the cross-sectional area. Such tracking systems are complex and expensive, and flat modules cannot utilize omnidirectional incident light.

Advanced Recovery and High-Sensitive Properties of Memristor-Based Gas Sensor Devices Operated at Room Temperature.

Fast recovery, high sensitivity, high selectivity, and room temperature (RT) sensing characteristics of NO gas sensors are essential for environmental monitoring, artificial intelligence, and inflammatory diagnosis of asthma patients. However, the conventional semiconductor-type gas sensors have poor sensing characteristics that need to be solved, such as slow recovery speeds (>360 s), low sensitivity (3.8), and high operating temperatures (>300 °C).

Highly stretchable large area woven, knitted and robust braided textile based interconnection for stretchable electronics.

With the rapid development of stretchable and wearable technologies, stretchable interconnection technology also demanded along it. Stretchable interconnections should have high stretchability and stable conductivity for use as an electrode. In addition, to develop to commercialization scale from research scale, a simple fabrication process that can be scaled up, and the stretchable interconnection should be able to be electrically connected to devices or modules directly.

Omni-directional light capture in PERC solar cells enhanced by stamping hierarchical structured silicone encapsulation that mimics leaf epidermis.

Conventional crystalline silicon solar cell photovoltaic module technology requires much more development due to the challenges of efficiency loss and reliability problems such as browning damage. As an alternative to conventional ethylene-vinyl acetate (EVA)-glass encapsulation, silicone-based encapsulation is a promising innovation. Added to the many advantages of silicone based encapsulation for Si solar cells, here we present surface modification of silicone encapsulation with hierarchical structures inspired by leaf epidermis structures that improve light capture and hydrophobicity of the module surface using a simple, large-area silane and ozone treatment technique.

Fractal solar cell array for enhanced energy production: applying rules underlying tree shape to photovoltaics.

Plants and photovoltaics share the same purpose as harvesting sunlight. Therefore, botanical studies could lead to new breakthroughs in photovoltaics. However, the basic mechanism of photosynthesis is different to semiconductor-based photovoltaics and the gap between photosynthesis and solar cells must be bridged before we can apply the botanical principles to photovoltaics.

Omni-direction PERC solar cells harnessing periodic locally focused light incident through patterned PDMS encapsulation.

Photovoltaic panels based on crystalline Si solar cells are the most widely utilized renewable source of electricity, and there has been a significant effort to produce panels with a higher energy conversion efficiency. Typically, these developments have focused on cell-level device modifications to restrict the recombination of photo-generated charge carriers, and concepts such as back surface field, passivated emitter and rear contact (PERC), interdigitated back contact, and heterojunction with intrinsic thin layer solar cells have been established. Here, we propose quasi-Fermi level control using periodic local focusing of incident light by encapsulation with polydimethylsiloxane to improve the performance of solar cells at the module-level; such improvements can complement cell-level enhancements.

Omnidirectional Light Capture by Solar Cells Mimicking the Structures of the Epidermal cells of Leaves.

It is important to develop solar cells that can capture and utilize omnidirectional light in urban environments, where photovoltaic (PV) devices are installed in fixed directions. We report a new design for such light capture, which mimics the structure of a leaf epidermis. First, we analyzed the epidermal structures of different plant species in detail so that we could copy them and fabricate light-trapping layers with different shapes: as lens arrays, pillars, and lens arrays with rough surfaces.

Leaf Anatomy and 3-D Structure Mimic to Solar Cells with light trapping and 3-D arrayed submodule for Enhanced Electricity Production.

Plant leaves are efficient light scavengers. We take a 'botanical approach' toward the creation of next-generation photovoltaic cells for urban environments. Our cells exhibit high energy conversion efficiency under indirect weak illumination.

Three-Dimensional Textile Platform for Electrochemical Devices and its Application to Dye-Sensitized Solar Cells.

The demand for easy-to-use portable electric devices that are combined with essential items in everyday life, such as apparel, has increased. Hence, significant research has been conducted into the development of wearable technology by fabrication of electronic devices with a textile structure based on fiber or fabric. However, the challenge to develop a fabrication method for wearable devices based on weaving or sewing technology still remains.

Forming-Free One-Selector/One-Resistor Characteristics of Oxygen-Rich ITO Based Transparent Resistive Switching Memory via Defect Engineering Using the Reactive Sputtering Process.

In recent research of resistive random access memory (RRAM), solving the degradation phenomenon induced by both a high forming voltage to form the conducting filaments (CFs) and a high reset current is one of the main issues encountered. In this study, to overcome these problems, we propose forming-free bipolar resistive switching (BRS) behaviors by employing an ITO film with abundant oxygen vacancies, instead of conventional CF based RRAM requiring a forming process, and systematically investigate the feasibility of forming free BRS behaviors and a possible switching mechanism. Compared to conventional CF based RRAM devices, it is possible for the proposed devices to achieve stable BRS properties (i.

Improvement in Energy Conversion Efficiency by Modification of Photon Distribution within the Photoanode of Dye-Sensitized Solar Cells.

The dye-sensitized solar cell (DSSC) is a potential alternative to the widely used Si-based solar cell, with several advantages including higher energy conversion efficiency under weak and indirect illumination conditions, and the possibility of practical application in urban life due to their exterior characteristics. However, despite these advantages, the energy conversion efficiency of DSSCs has remained low at ∼10%. To improve the efficiency of DSSCs, research has been done on modifying the materials used in DSSC component parts, such as the photoanode, electrolyte, and counter electrode.

High Energy Conversion Efficiency with 3-D Micro-Patterned Photoanode for Enhancement Diffusivity and Modification of Photon Distribution in Dye-Sensitized Solar Cells.

Dye sensitize solar cells (DSSCs) have been considered as the promising alternatives silicon based solar cell with their characteristics including high efficiency under weak illumination and insensitive power output to incident angle. Therefore, many researches have been studied to improve the energy conversion efficiency of DSSCs. However the efficiency of DSSCs are still trapped at the around 10%.

Monolithic-Structured Single-Layered Textile-Based Dye-Sensitized Solar Cells.

Textile-structured solar cells are frequently discussed in the literature due to their prospective applications in wearable devices and in building integrated solar cells that utilize their flexibility, mechanical robustness, and aesthetic appearance, but the current approaches for textile-based solar cells-including the preparation of fibre-type solar cells woven into textiles-face several difficulties from high friction and tension during the weaving process. This study proposes a new structural concept and fabrication process for monolithic-structured textile-based dye-sensitized solar cells that are fabricated by a process similar to the cloth-making process, including the preparation of wires and yarns that are woven for use in textiles, printed, dyed, and packaged. The fabricated single-layered textile-based dye-sensitized solar cells successfully act as solar cells in our study, even under bending conditions.

Insertion of Dye-Sensitized Solar Cells in Textiles using a Conventional Weaving Process.

Increasing demands for wearable energy sources and highly flexible, lightweight photovoltaic devices have stimulated the development of textile-structured solar cells. However, the former approach of wire-type solar cell fabrication, followed by weaving of these devices, has had limited success, due to device failure caused by high friction forces and tension forces during the weaving process. To overcome this limitation, we present a new approach for textile solar cell fabrication, in which dye-sensitized solar cell (DSSC) electrodes are incorporated into the textile during the weaving process, using the textile warp as a spacer to maintain the DSSC structure.

Size-dependent resistive switching properties of the active region in nickel nitride-based crossbar array resistive random access memory.

The size-dependent resistive switching (RS) properties of the active region in a 1 x 1 NiN-based crossbar array (CBA) resistive random access memory (ReRAM) are investigated in the range of 2 x 2 μm2 to 8 x 8 μm2. In the forming test, the forming voltage is reduced by decreasing the cell size of the active region. Compared to the 8 x 8 μm2 CBA ReRAM, the forming voltage of the 2 x 2 μm2 CBA ReRAM was reduced from 8 V to 6.

Highly flexible dye-sensitized solar cells produced by sewing textile electrodes on cloth.

Textile forms of solar cells possess special advantages over other types of solar cells, including their light weight, high flexibility, and mechanical robustness. Recent demand for wearable devices has promoted interest in the development of high-efficiency textile-based solar cells for energy suppliers. However, the weaving process occurs under high-friction, high-tension conditions that are not conducive to coated solar-cell active layers or electrodes deposited on the wire or strings.

Transparent multi-level resistive switching phenomena observed in ITO/RGO/ITO memory cells by the sol-gel dip-coating method.

A reduced graphene oxide (RGO)-based transparent electronic memory cell with multi-level resistive switching (RS) was successfully realized by a dip-coating method. Using ITO/RGO/ITO structures, the memory device exhibited a transmittance above 80% (including the substrate) in the visible region and multi-level RS behavior in the 00, 01, 10, and 11 states by varying the pulse height from 2 V to 7 V. In the reliability test, the device exhibited a good endurance of over 10(5) cycles and a long data retention of over 10(5) s at 85°C in each state.

Effect of nanopyramid bottom electrodes on bipolar resistive switching phenomena in nickel nitride films-based crossbar arrays.

The improved resistive switching (RS) performance characteristics of nickel nitride (NiN) films-based crossbar array (CBA) memory resistors-such as reduction in the operating voltages, reset current and current/voltage variations; no initial forming process; and set/reset speeds--are demonstrated using nanopyramid-patterned (NPP) platinum-bottom electrodes. Compared with a conventional CBA sample with flat-bottom electrodes, both the voltage and the current of the set and reset operations are respectively reduced when NPP samples are used. The drastic reduction in the variation of the operating voltage and current is of particular interest.

Crystal splitting and enhanced photocatalytic behavior of TiO2 rutile nano-belts induced by dislocations.

Crystal splitting and enhanced photocatalytic activities caused by implied dislocations were observed in hierarchical TiO(2) nano-architectures prepared by one-pot hydrothermal synthesis in concentrated HCl. Microstructural observation revealed that the nanowires formed by continuous splitting of TiO(2) nano-belts, which is caused by a lattice misorientation of about 6°, were generated by an array of dislocations. In addition, the larger amount of dislocations implied in TiO(2) nano-architectures induces higher photocatalytic activities under ultra-violet illumination.