Evaluation of a same-metal PCB-based three-electrode system impedance studies using potassium ferricyanide.

We report for the first time the successful acquisition of electrochemical impedance spectroscopy data using an unconventional same-metal PCB-based three-electrode system. Conventional three-electrode systems primarily require expensive and bulky electrodes, and a high volume of analytes to conduct electrochemical impedance spectroscopy studies. The miniaturized PCB-based three-electrode system used in this work requires only trace amounts of analytes in the order of 10-20 μL owing to the design of the electrode sensor.

Semiconductive-like behaviour and negative differential effect observed in self-assembled riboflavin layer on gold electrodes.

Riboflavin or vitamin B2 plays significant roles in metabolic reactions and energy production, establishing it as an important research subject in biology and medicine. While there are numerous riboflavin-related publications in these fields, interrogation of its electronic properties in relation to the physiological function at the cellular level remains obscure due to technological challenges. However, progress in molecular electronics and the discovery of the semiconductor-like behaviour of biomolecules in recent times have initiated growing interest in exploring the electronic properties of these materials for potential bioelectronic device applications.

A Review of Contact Electrification at Diversified Interfaces and Related Applications on Triboelectric Nanogenerator.

The triboelectric nanogenerator (TENG) can effectively collect energy based on contact electrification (CE) at diverse interfaces, including solid-solid, liquid-solid, liquid-liquid, gas-solid, and gas-liquid. This enables energy harvesting from sources such as water, wind, and sound. In this review, we provide an overview of the coexistence of electron and ion transfer in the CE process.

Novel same-metal three electrode system for cyclic voltammetry studies.

Conventional three-electrode systems used in electrochemical measurement demand time-consuming and maintenance intensive procedures to enable accurate and repeatable electrochemical measurements. Traditionally, different metal configurations are used to establish the electrochemical gradient required to acquire the redox activity, and vary between different electrochemical measurement platforms. However, in this work, we report using the same metal (gold) for the counter, working and reference electrodes fabricated on a miniaturized printed circuit board (PCB) for a much simpler design.

The use of marine microalgae in microbial fuel cells, photosynthetic microbial fuel cells and biophotovoltaic platforms for bioelectricity generation.

Algal green energy has emerged as an alternative to conventional energy production using fossil fuels. Microbial fuel cells (MFCs), photosynthetic microbial fuel cells (PMFCs) and biophotovoltaic (BPV) platforms have been developed to utilize microalgae for bioelectricity generation, wastewater treatment and biomass production. There remains a lack of research on marine microalgae in these systems, so to the best of our knowledge, all information on their integration in these systems have been gathered in this review, and are used to compare with the interesting studies on freshwater microalgae.

Langmuir-Blodgett Graphene-Based Films for Algal Biophotovoltaic Fuel Cells.

The prevalence of photosynthesis, as the major natural solar energy transduction mechanism or biophotovoltaics (BPV), has always intrigued mankind. Over the last decades, we have learned to extract this renewable energy through continuously improving solid-state semiconductive devices, such as the photovoltaic solar cell. Direct utilization of plant-based BPVs has, however, been almost impracticable so far.

Publisher Correction: Electronic Properties of Synthetic Shrimp Pathogens-derived DNA Schottky Diodes.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Electronic Properties of Synthetic Shrimp Pathogens-derived DNA Schottky Diodes.

The exciting discovery of the semiconducting-like properties of deoxyribonucleic acid (DNA) and its potential applications in molecular genetics and diagnostics in recent times has resulted in a paradigm shift in biophysics research. Recent studies in our laboratory provide a platform towards detecting charge transfer mechanism and understanding the electronic properties of DNA based on the sequence-specific electronic response, which can be applied as an alternative to identify or detect DNA. In this study, we demonstrate a novel method for identification of DNA from different shrimp viruses and bacteria using electronic properties of DNA obtained from both negative and positive bias regions in current-voltage (I-V) profiles.

Preparation of Chiral Polydiacetylene Films by Using Three-Photon Polymerization.

Asymmetric polymerization of polydiacetylene (PDA) from commercially available achiral derivative of diacetylene monomer using circularly polarized pulse laser is demonstrated. Chiral source was only circularly polarized laser, and irradiation of left- and right-circularly polarized light effectively promoted the polymerization of chiral PDAs with opposite handedness. Difference between the laser wavelength and the absorption peak of monomer suggested the contribution of the multiphoton excitation to the photo-polymerization.

Carrier Transport Mechanism in Single Crystalline Organic Semiconductor Thin Film Elucidated by Visualized Carrier Motion.

Time-resolved microscopic second harmonic generation (TRM-SHG) measurement was conducted to evaluate temperature dependence of the anisotropic carrier transport process in 6,13-Bis(triisopropylsilylethynyl) (TIPS) pentacene single crystalline domains for two orthogonal directions. Enhancement of the electric field induced SHG (EFI-SHG) signal at the electrode edge at low temperature suggests the presence of potential drop in the injection process. We directly evaluated temperature dependence of the carrier mobility by taking into account the potential drop, and concluded that the Marcus theory is appropriate to interpret the carrier transport in anisotropic TIPS pentacene thin film.

Evaluation of Thermal Stability of Organic Electro-Optic Device by Using Thermally Stimulated Current.

Thermally stimulated current (TSC) measurement was employed to study the thermal stability of electro-optic (EO) polymers, i.e., guest/host polymer DR1/PMMA and side-chain polymer PMMA-co-DR1.

Study of Electrical Conduction Mechanism of Organic Double-Layer Diode Using Electric Field Induced Optical Second Harmonic Generation Measurement.

By using electric field induced optical second harmonic generation (EFISHG) and current voltage (I-V) measurements, we studied the electrical transport mechanism of organic double-layer diodes with a structure of Au/N, N'-di-[(1-naphthyl)-N, N'-diphenyl]-(1,1'-biphenyl)-4,4'-diamine (a-NPD)/poly(methyl methacrylate) (PMMA)/indium zinc oxide (IZO). Here the α-NPD is a carrier transport layer and the PMMA is an electrical insulating layer. The current level was very low, but the I-V characteristics showed a rectifying behavior.

Influence of Pentacene Interface Layer in ITO/α-NPD/Alq3/Al Organic Light Emitting Diodes by Time-Resolved Electric-Field-Induced Optical Second-Harmonic Generation Measurement.

By using I-V, EL-V, displacement current measurement (DCM) and time-resolved electric-field-induced optical second-harmonic generation (TR-EFISHG) measurement, we studied the influence of interface pentacene layer inserted between ITO and a-NPD layers in ITO/α-NPD/Alq3/Al OLEDs. All experiments were carried out for the OLEDs with and without a pentacene interface layer. The I-V and EL-V measurements showed the decrease of operating voltage of EL, the DCM showed the lowering of inception voltage of carrier injection by inserting a pentacene interface layer.

Measuring the Electronic Properties of DNA-Specific Schottky Diodes Towards Detecting and Identifying Basidiomycetes DNA.

The discovery of semiconducting behavior of deoxyribonucleic acid (DNA) has resulted in a large number of literatures in the study of DNA electronics. Sequence-specific electronic response provides a platform towards understanding charge transfer mechanism and therefore the electronic properties of DNA. It is possible to utilize these characteristic properties to identify/detect DNA.

Protolytic decomposition of n-octane on graphite at near room temperature.

Graphite basal surface is inert, and decomposition of n-alkanes on the graphite surface has not been discovered. We here report the evidence of decomposition of n-octanes on highly oriented pyrolytic graphite (HOPG) surface, heat-treated up to 1200 °C under high vacuum (10(-7) Pa), at near room temperatures. Using a temperature programmed desorption apparatus equipped with a quadrupole mass spectrometer showed the production of hydrogen molecules, methane, and ethane, suggesting that the protonation of n-octane takes place on graphite surface at near room temperature.

Optical second-harmonic generation measurement for probing organic device operation.

We give a brief overview of the electric-field induced optical second-harmonic generation (EFISHG) technique that has been used to study the complex behaviors of organic-based devices. By analyzing EFISHG images of organic field-effect transistors, the in-plane two-dimensional distribution of the electric field in the channel can be evaluated. The susceptibility tensor of the organic semiconductor layer and the polarization of the incident light are considered to determine the electric field distribution.

Analysis of Carrier Transport of Organic Devices by Using Nonlinear Optical Polarization.

In this review, we discuss the Maxwell-Wagner (MW) effect model analysis of organic devices and time-resolved optical second harmonic generation (TR-EFISHG) measurement that is available for directly probing carrier motion in organic semiconductor devices. Using these, we show that organic field effect transistor as well organic double-layer device operation is analyzed well, and we can make clear the mechanism of these organic devices' operation. Finally, we conclude that the dielectric physics approach using the MW model analysis and the TR-EFISHG experiment is useful to study carrier transport mechanism of organic devices.

Direct probing of contact electrification by using optical second harmonic generation technique.

Contact electrification between two different materials is one of the oldest fields of study in solid-state physics. Here, we introduced an innovative system based on optical electric-field-induced second harmonic generation (EFI-SHG) technique that can directly monitor the dynamic performance of the contact electrification on the surface of polyimide film. After the contact, the EFI-SHG system visualized briefly three relaxations of the tribo-induced charges on the surface of a polyimide film, a fast relaxation within 3 min followed by two much slower relaxations, which were possibly related to different charge diffusion routes.

Catalyst-Free Plasma Enhanced Growth of Graphene from Sustainable Sources.

Details of a fast and sustainable bottom-up process to grow large area high quality graphene films without the aid of any catalyst are reported in this paper. We used Melaleuca alternifolia, a volatile natural extract from tea tree plant as the precursor. The as-fabricated graphene films yielded a stable contact angle of 135°, indicating their potential application in very high hydrophobic coatings.

Thiol modified chitosan self-assembled monolayer platform for nucleic acid biosensor.

A self-assembled monolayer (SAM) of thiol modified chitosan (SH-CHIT), with thioglycolic acid (TGA) as a modifier to bestow thiol groups, has been prepared onto gold (Au)-coated glass plates for fabrication of the nucleic acid biosensor. The chemical modification of CHIT via TGA has been evidenced by Fourier transform infrared spectroscopy (FT-IR) studies, and the biocompatibility studies reveal that CHIT retains its biocompatible nature after chemical modification. The electrochemical studies conducted onto SH-CHIT/Au electrode reveal that thiol modification in CHIT amino end enhances the electrochemical behavior indicating that it may be attributed to delocalization of electrons in CHIT skeleton that participates in the resonance process.

Energetic alignment in nontoxic SnS quantum dot-sensitized solar cell employing spiro-OMeTAD as the solid-state electrolyte.

An environmentally friendly solid-state quantum dot sensitized solar cell (ss-QDSSC) was prepared by combining colloidal SnS QDs as the sensitizer and organic hole scavenger spiro-OMeTAD (2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)9,9'-spirobifluorene) as the solid-state electrolyte, and the energy alignment of SnS and TiO was investigated. The bandgap of colloidal SnS QDs increased with decreasing particle size from 14 to 4 nm due to an upshift of the conduction band and a downshift of the valence band. In TiO/SnS heterojunctions, the conduction band minimum (CBM) difference between TiO and SnS was as large as ∼0.

Enhanced conductivity and gating effect of p-type Li-doped NiO nanowires.

Li doped NiO nanowires with a diameter smaller than 100 nm were synthesized by electrospinning. The nanowires exhibit p-type characteristics with improved electrical conductivity through Li doping. Moreover, an enhanced gating effect was obtained in Li-NiO-nanowire-based field effect transistors (FETs), which hold great potential in transparent optoelectronics.

Voltage-induced chromatic phase transition in ferrocene substituted polydiacetylene thin films.

A novel ferrocene substituted PDA (FEPDA) material was synthesized and its chromatic phase transition behavior was studied under the application of a negative bias voltage. By the combination with CMS techniques, FEPDA materials could be used as a probe for mapping the topographic carrier density distribution in organic devices.

Study of relaxation process of dipalmitoyl phosphatidylcholine monolayers at air-water interface: effect of electrostatic energy.

The instability of organic monolayer composed of polar molecules at the air-water interface has been a spotlight in interface science for many decades. However, the effect of electrostatic energy contribution to the free energy in the system is still not understood. Herein, we investigate the mechanical and electrical properties by studying the isobaric relaxation process of a dipalmitoyl phosphatidylcholine monolayer on water subphase with various concentrations of divalent ions to reveal the effect of electrostatic energy on thermodynamics and kinetics of the collapse mechanism.

Noninvasive imaging of prefrontal activation during attention-demanding tasks performed while walking using a wearable optical topography system.

Optical topography (OT) based on near-infrared spectroscopy is a noninvasive technique for mapping the relative concentration changes in oxygenated and deoxygenated hemoglobin (oxy- and deoxy-Hb, respectively) in the human cerebral cortex. In our previous study, we developed a small and light wearable optical topography (WOT) system that covers the entire forehead for monitoring prefrontal activation. In the present study, we examine whether the WOT system is applicable to OT measurement while walking, which has been difficult with conventional OT systems.