Stabilization of Perovskite Solar Cells: Recent Developments and Future Perspectives.

Exceptional power conversion efficiency (PCE) of 25.7% in perovskite solar cells (PSCs) has been achieved, which is comparable with their traditional rivals (Si-based solar cells). However, commercialization-worthy efficiency and long-term stability remain a challenge.

Asymmetric Bipolar Resistive Switching of Halide Perovskite Film in Contact with TiO Layer.

Halide perovskite materials such as methylammonium lead iodide (CHNHPbI) have attracted considerable interest for the resistive random-access memory applications, which exploit a dramatic change in the resistance by an external electric bias. In many semiconductor films, the drift, accumulation, and chain formation of defects explain the change in the resistance by an external bias. This study demonstrates that the interface of CHNHPbI with TiO has a significant impact on the formation and rupture of defect chains and causes the asymmetric bipolar resistive switching in the Au/CHNHPbI/TiO/FTO device (FTO = fluorine-doped tin oxide).

Effects of Surface Modifications to Single and Multilayer Graphene Temperature Coefficient of Resistance.

Interfacial effects on single-layer graphene (SLG) or multilayer graphene (MLG) properties greatly affect device performance. Thus, the effect of the interface on the temperature coefficient of resistance (TCR) on SLG and MLG due to surface-deposited core-shell metallic nanoparticles (MNPs) and various substrates was experimentally investigated. Observed substrates included glass, SiO, and SiN.

An effective datasets describing antimicrobial peptide produced from - purification and mode of action determined by molecular docking.

Most of the probiotics Bacterial cells, express native antibacterial genes, resulting in the production of, antimicrobial peptides, which have various applications in biotechnology and drug development. But the identification of antibacterial peptide, structural characterization of antimicrobial peptide and prediction on mode of action. Regardless of the significance of protein manufacturing, three individual factors are required for the production method: gene expression, stabilization and specific peptide purification.

Role of the Interface between Ag and ZnO in the Electric Conductivity of Ag Nanoparticle-Embedded ZnO.

The addition of Ag nanoparticles (Ag NPs) with an average size of 30 nm into ZnO increases the electric conductivity up to 1000 times. While a similar increase in the conductivity is observed in a mixture of Ag nanoparticles and Al-doped ZnO (AZO) films, a physical mechanism underlying the change in electric conductivity is not the same for Ag NP-added ZnO and Ag NP-added AZO. In Ag NP-added ZnO, an ohmic junction is formed at the ZnO-Ag interface, and electrons are accumulated in ZnO near the ZnO-Ag interface until electron-rich islands are connected.

Unveiling the potentials of bacteriocin (Pediocin L50) from Pediococcus acidilactici with antagonist spectrum in a Caenorhabditis elegans model.

Human-milk-based probiotics play a major role in the early colonization and protection of infants against gastrointestinal infection. We investigated potential probiotics in human milk. Among 41 Lactic acid bacteria (LAB) strains, four strains showed high antimicrobial activity against Escherichia coli 0157:H7, Listeria monocytogenes ATCC 15313, Bacillus cereus ATCC 14576, Staphylococcus aureus ATCC 19095, and Helicobacter pylori.

Highly Bendable Flexible Perovskite Solar Cells on a Nanoscale Surface Oxide Layer of Titanium Metal Plates.

We report highly bendable and efficient perovskite solar cells (PSCs) that use thermally oxidized layer of Ti metal plate as an electron transport layer (ETL). The power conversion efficiency (PCE) of flexible PSCs reaches 14.9% with a short-circuit current density (J) of 17.

Enhanced viscoelastic property of iron oxide nanoparticle decorated organoclay fluid under magnetic field.

Stable hydrophobic nanocomposites of magnetic nanoparticles and clay are prepared by the self-assembly of magnetite (FeO) nanoparticles on surfaces of exfoliated clay platelets. Due to the attractive interaction between hydrophobic groups, oleic acid coated nanoparticles are strongly attached to the surface of cetyl trimethylammonium cation coated clay platelets in organic media. Crystal structure and magnetic property of composite particles are examined using electron microscopy, x-ray diffractometer and vibration sample magnetometer.

A Light Illumination Enhancement Device for Photoacoustic Imaging: In Vivo Animal Study.

Photoacoustic (PA) imaging detects acoustic signals generated by thermal expansion of a light-excited tissue or contrast agents. PA signal amplitude and image quality directly depend on the light fluence at the target depth. With conventional PA imaging systems, approximately 30% energy of incident light at the near-infrared region would be lost due to reflection on the skin surface.

Novel Carrier Doping Mechanism for Transparent Conductor: Electron Donation from Embedded Ag Nanoparticles to the Oxide Matrix.

A trade-off between the carrier concentration and carrier mobility is an inherent problem of traditional transparent conducting oxide (TCO) films. In this study, we demonstrate that the electron concentration of TCO films can be increased without deteriorating the carrier mobility by embedding Ag nanoparticles (NPs) into Al-doped ZnO (AZO) films. An increment of Ag NP content up to 0.

Low-Temperature Modification of ZnO Nanoparticles Film for Electron-Transport Layers in Perovskite Solar Cells.

An electron-transport layer (ETL) that selectively collects photogenerated electrons is an important constituent of halide perovskite solar cells (PSCs). Although TiO films are widely used as ETL of PSCs, the processing of TiO films with high electron mobility requires high-temperature annealing and TiO dissociates the perovskite layer through a photocatalytic reaction. Here, we report an effective surface-modification method of a room-temperature processed ZnO nanoparticles (NPs) layer as an alternative to the TiO ETL.

Room Temperature Deposition of Crystalline Nanoporous ZnO Nanostructures for Direct Use as Flexible DSSC Photoanode.

A facile approach to fabricate dye-sensitized solar cells (DSSCs) is demonstrated by depositing (001) oriented zinc oxide (ZnO) nanostructures on both glass and flexible substrates at room temperature using pulsed laser deposition. Unique crystallographic characteristics of ZnO combined with highly non-equilibrium state of pulsed laser-induced ablated species enabled highly crystalline ZnO nanostructures without aid of any chemically induced additives or organic/inorganic impurities at room temperature. Film morphology as well as internal surface area is tailored by varying ambient oxygen pressure and deposition time.

Heteroepitaxial Cu2O thin film solar cell on metallic substrates.

Heteroepitaxial, single-crystal-like Cu2O films on inexpensive, flexible, metallic substrates can potentially be used as absorber layers for fabrication of low-cost, high-performance, non-toxic, earth-abundant solar cells. Here, we report epitaxial growth of Cu2O films on low cost, flexible, textured metallic substrates. Cu2O films were deposited on the metallic templates via pulsed laser deposition under various processing conditions to study the influence of processing parameters on the structural and electronic properties of the films.

Reduced Graphene Oxide/Mesoporous TiO2 Nanocomposite Based Perovskite Solar Cells.

We report on reduced graphene oxide (rGO)/mesoporous (mp)-TiO2 nanocomposite based mesostructured perovskite solar cells that show an improved electron transport property owing to the reduced interfacial resistance. The amount of rGO added to the TiO2 nanoparticles electron transport layer was optimized, and their impacts on film resistivity, electron diffusion, recombination time, and photovoltaic performance were investigated. The rGO/mp-TiO2 nanocomposite film reduces interfacial resistance when compared to the mp-TiO2 film, and hence, it improves charge collection efficiency.

Epitaxial 1D electron transport layers for high-performance perovskite solar cells.

We demonstrate high-performance perovskite solar cells with excellent electron transport properties using a one-dimensional (1D) electron transport layer (ETL). The 1D array-based ETL is comprised of 1D SnO2 nanowires (NWs) array grown on a F:SnO2 transparent conducting oxide substrate and rutile TiO2 nanoshells epitaxially grown on the surface of the 1D SnO2 NWs. The optimized devices show more than 95% internal quantum yield at 750 nm, and a power conversion efficiency (PCE) of 14.

Hierarchical graphene/metal grid structures for stable, flexible transparent conductors.

We report an experimental study on the fabrication and characterization of hierarchical graphene/metal grid structures for transparent conductors. The hierarchical structure allows for uniform and local current conductivity due to the graphene and exhibits low sheet resistance because the microscale silver grid serves as a conductive backbone. Our samples demonstrate 94% diffusive transmission with a sheet resistance of 0.

Designing metal hemispheres on silicon ultrathin film solar cells for plasmonic light trapping.

We systematically investigate the design of two-dimensional silver (Ag) hemisphere arrays on crystalline silicon (c-Si) ultrathin film solar cells for plasmonic light trapping. The absorption in ultrathin films is governed by the excitation of Fabry-Perot TEMm modes. We demonstrate that metal hemispheres can enhance absorption in the films by (1) coupling light to c-Si film waveguide modes and (2) exciting localized surface plasmon resonances (LSPRs).

Improved osteoblast response to UV-irradiated PMMA/TiO2 nanocomposites with controllable wettability.

Osteoblast response was evaluated with polymethylmethacrylate (PMMA)/titanium dioxide (TiO2) nanocomposite thin films that exhibit the controllable wettability with ultraviolet (UV) treatment. In this study, three samples of PMMA/TiO2 were fabricated with three different compositional volume ratios (i.e.

Uniform and ordered copper nanomeshes by microsphere lithography for transparent electrodes.

We report a comprehensive simulation and experimental study on the optical and electronic properties of uniform and ordered copper nanomeshes (Cu NMs) to determine their performance for transparent conductors. Our study includes simulations to determine the role of propagating modes in transmission and experiments that demonstrate a scalable, facile microsphere-based method to fabricate NMs on rigid quartz and flexible polyethylene terephthalate substrates. The fabrication method allows for precise control over NM morphology with near-perfect uniformity and long-range order over large areas on rigid substrates.

Dye Sensitized Solar Cells for Economically Viable Photovoltaic Systems.

TiO2 nanoparticle-based dye sensitized solar cells (DSSCs) have attracted a significant level of scientific and technological interest for their potential as economically viable photovoltaic devices. While DSSCs have multiple benefits such as material abundance, a short energy payback period, constant power output, and compatibility with flexible applications, there are still several challenges that hold back large scale commercialization. Critical factors determining the future of DSSCs involve energy conversion efficiency, long-term stability, and production cost.

Synthesis and characteristics of tb-doped Y2SiO5 nanophosphors and luminescent layer for enhanced photovoltaic cell performance.

Nanophosphors based on green emitting terbium doped yttrium silicates with the general formula Y2SiO5:Tb3+ with a size of 30-60 nm were synthesized by the hydrothermal method. The prepared nanophosphors were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy and fluorescence spectroscopy. It was found that the nanophosphors crystallize in an X1-type monoclinic structure (P2(1)/c) and absorb UV light from 220 to 300 nm which they then down-convert into visible-light (strong green emission at around 545 nm (5D4-->7F(J.

Facile control of surface wettability in TiO2/poly(methyl methacrylate) composite films.

A facile method to produce very hydrophobic surface was developed simply using the mixture of TiO(2) nanoparticles and poly(methyl methacrylate) (PMMA). When the volume ratio of TiO(2) to PMMA is between 35 vol.% and 50 vol.

Rheological behavior of clay-nanoparticle hybrid-added bentonite suspensions: specific role of hybrid additives on the gelation of clay-based fluids.

Two different types of clay nanoparticle hybrid, iron oxide nanoparticle clay hybrid (ICH) and Al(2)O(3)-SiO(2) nanoparticle clay hybrid (ASCH), were synthesized and their effects on the rheological properties of aqueous bentonite fluids in steady state and dynamic state were explored. When ICH particles were added, bentonite particles in the fluid cross-link to form relatively well-oriented porous structure. This is attributed to the development of positively charged edge surfaces in ICH that leads to strengthening of the gel structure of the bentonite susensions.

Surfactant-assisted shape evolution of thermally synthesized TiO2 nanocrystals and their applications to efficient photoelectrodes.

TiO2 nanocrystals were synthesized via a two-phase thermal process, and the shape of the nanocrystals was controlled from nanospheres to nanorods by the ratio of two surfactants. The shape control of nanocrystals was ascribed to the selective adsorption of the two surfactants. The shape of TiO2 nanocrystals influenced the photocatalytic performances of the photoelectrodes through two compromising factors: the relative surface area and the electron transport.