A membrane- free cation selective water- gated transistor

Sensors for the detection of waterborne cations are of great practical interest, and chemistry has synthesised a formidable catalogue of cation selective complexation agents (‘ionophores’) as selective sensitisers (e.g. 9-13, 15-19, 28, 29). Current ionophore- based sensors separate the complexation of the cation by the ionophore, and the transduction of complexation into an electrical signal, into separate components. We here unite both functions into a single, sensitised semiconducting layer of a water- gated organic thin film transistor (OTFT). The resulting OTFT transduces waterborne cations into an electrical signal with same selectivity, sensitivity, and limit of detection as established sensors at much simplified preparation and operation. This opens a new route to apply the ‘ionophore’ family of functional organic materials in practical cation sensors

Market orientation in higher education and innovativeness as a mediating variable

Market orientation (MO) is an operationalization of a marketing concept and considered vital to enhance organization profitability and sustainability especially for businesses. However, efforts to investigate MO in the educational context have not been extensively conducted in comparison to those in the business settings. This research assessed the influence of top management emphasis and internal market orientation (IMO) as antecedents to MO in higher education institutions (HEIs). It also examined the effect of IMO and MO on HEIs perceived performance. In addition, the mediation role of innovativeness to the relationship of MO and perceived performance was investigated. The unit of analysis in this research was an educational institution that provides tertiary education under the supervision of the Ministry of Education in Saudi Arabia. In this quantitative cross sectional study, the whole population was targeted and data was collected online. There were 263 usable responses from 537, representing 48.97% response rate. The findings of this research indicated that there is a positive relationship between top management emphasis and IMO, as well as with MO. Results also showed that IMO was found to be positively related to MO. On the contrary, the relationship between IMO and HEIs perceived performance was found to be insignificant. Besides that, the study disclosed that MO is positively related to HEIs perceived performance. In this study, innovativeness was found to be partially mediating the relationship between MO and perceived performance. The research has illustrated the application of MO in the educational setting of a developing country. Additionally, the findings of the study will help academic managers and education policy makers in Saudi Arabia to develop market oriented strategies to improve HEIs performance

CaO impregnated highly porous honeycomb activated carbon from agriculture waste: symmetrical supercapacitor study

This study presents the electrochemical studies of activated carbon prepared from palm kernel shell (ACPKS), with CaO impregnation. The CaO is obtained from chicken eggshell waste to produce CaO/ACPKS, which shows highly porous honeycomb structure with homogeneous distribution of CaO nanoparticles (30–50 nm in size). The prepared materials are evaluated as supercapacitor electrodes by testing their electrochemical characteristics. A high specific capacitance value of 222 F g−1 at 0.025 A g−1 is obtained for CaO/ACPKS, which is around three times higher than that for ACPKS (76 F g−1). In addition, electrochemical impedance data show lower impedance for CaO/ACPKS. Lastly, a practical symmetrical supercapacitor is fabricated by CaO/ACPKS and its performance is discussed

A water-gated organic thin film transistor as a sensor for water-borne amines

The p-type semiconducting polymer Poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) displays innate sensitivity to water-borne amines. We demonstrate this with the help of water- gated PBTTT thin film transistors (TFTs). When octylamine is added to the gating water, TFTs respond with a significantly reduced saturated drain current. Underlying TFT drift is minimised by initial conditioning, and remaining drift can be accounted for by normalising current response to the current level under purge immediately before exposure. Normalised current response vs. amine concentration is reproducible between different transistors, and can be modelled by a Langmuir surface adsorption isotherm, which suggests physisorption of analyte at the PBTTT surface, rather than bulk penetration. Same PBTTT transistors do not respond to 1- octanol, confirming the specific affinity between amines and thiophene- based organic semiconductors

An ionic liquid-gated polymer thin film transistor with exceptionally low "on" resistance

We report the ionic liquid (IL) gating of a solution processed semiconducting polymer, poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT). IL gating relies on the poor solubility of PBTTT, which requires hot chlorinated benzenes for solution processing. PBTTT, thus, resists dissolution even in IL, which otherwise rapidly dissolves semiconducting polymers. The resulting organic thin film transistors (OTFTs) display low threshold, very high carrier mobility (>3 cm2/Vs), and deliver high currents (in the order of 1 mA) at low operational voltages. Such OTFTs are interesting both practically, for the addressing of current-driven devices (e.g., organic LEDs), and for the study of charge transport in semiconducting polymers at very high carrier density

One-step production of pyrene-1-boronic acid functionalized graphene for dopamine detection

A facile molecular wedging method is used to exfoliate graphite flakes into graphene sheets, with concurrent functionalization to form pyrene-1-boronic acid functionalized graphene (PBA/G). Different techniques are used to characterize the prepared materials such as field emission scanning electron microscope, energy dispersive X-ray analyzer, Raman, Fourier transformed infrared spectroscopy and fluorescence spectroscopy to evaluate their structural and morphological characteristics. The intercalation of PBA into graphite sheets, followed by exfoliation can be observed under the electron microscope. Elemental analyses show that the PBA acts more than intercalant, it is functionalized onto the graphene sheets upon exfoliation to form PBA/G. Raman analysis indicates PBA/G has a lower number of graphene layers as a result of successful exfoliation by PBA. Electrochemical impedance studies show that the PBA/G possesses high affinity for dopamine through the diol groups interaction, which renders it to have enhanced detection for dopamine

Magnetic Electrodeposition of the Hierarchical Cobalt Oxide Nanostructure from Spent Lithium-Ion Batteries: Its Application as a Supercapacitor Electrode

In this study, electrodeposition of cobalt oxide (Co3O4) from spent lithium-ion batteries is successfully enhanced by the magnetic field effect. In the presence of magnetic field, well-defined hierarchical Co3O4 nanostructures with higher electroactive surface area are formed during the electrodeposition process. Electrochemical analysis shows that the enhanced Co3O4 nanostructures exhibit excellent charge storage capabilities of 1273 F g–1 at 1 A g–1, approximately 4 times higher than the electrodeposited Co3O4 that is formed without magnetic field effect. It also reveals the high cycling stability of enhanced Co3O4 nanostructures, with 96% capacitance retention at 5000 charge discharge cycles. The results manifest the enhancement of Co3O4 recovery from spent lithium-ion batteries, which can be the potential electrode material for supercapacitor application

Ferrocene functionalized multi-walled carbon nanotubes as supercapacitor electrodes

Modified multi-walled carbon nanotubes (MWCNTs) functionalized by a redox-active ferrocene (Fc-MWCNTs) were successfully synthesized to enhance the electrochemical performance of MWCNTs for supercapacitor application. The ferrocene moieties were attached to the surface of MWCNTs via a thiourea linker with anions-interacting capability. The Fc-MWCNTs were characterized using XPS, FTIR, SEM, TGA, DTG, and XRF methods. The electrochemical performance details were investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The Fc-MWCNTs electrode showed excellent capacity retention (90.8% over 5000 cycles) and a specific capacitance of 50 F g−1 at 0.25 A g−1 that is several times higher as compared to the pristine MWCNTs. The fabricated Fc-MWCNTs is proposed to be a suitable and promising candidate for energy storage material. de

Spin-valve Josephson junctions with perpendicular magnetic anisotropy for cryogenic memory

We demonstrate a Josephson junction with a weak link containing two ferromagnets with perpendicular magnetic anisotropy and independent switching fields in which the critical current can be set by the mutual orientation of the two layers. Such pseudospin-valve Josephson junctions are a candidate cryogenic memory in an all superconducting computational scheme. Here, we use Pt/Co/Pt/CoB/Pt as the weak link of the junction with dCo=0.6 nm, dCoB=0.3 nm, and dPt=5 nm and obtain a 60% change in the critical current for the two magnetization configurations of the pseudospin-valve. Ferromagnets with perpendicular magnetic anisotropy have advantages over magnetization in-plane systems, which have been exclusively considered at this point, as, in principle, the magnetization and magnetic switching of layers in the junction should not affect the in-plane magnetic flux