Electrochemical behaviour of LaCl3 at tungsten and aluminium cathodes in LiCl–KCl eutectic melt

The electrochemical behaviour of lanthanum was studied at inert tungsten electrode and reactive aluminium electrode in LiCl–KCl eutectic melt in the temperature range 698–798 K using transient electrochemical techniques. Reduction of La(III) to La(0) at the tungsten electrode takes place in a single step. The reduction shows quasi-reversible behaviour for polarization rates, 25 ≤ ν ≤ 150 mV s^?1 and is predominantly controlled by charge transfer of La(III) ions for scan rates higher than 75 mV s^?1. The heterogenous rate constant of the process was estimated from impedance spectroscopy and from the semi-integrals of the cyclic voltammograms. The redox potential of the La(III)/La couple at the Al electrode was observed to be more positive than that at the inert electrode. This potential shift is due to the lowering of the activity of La in the metal phase caused by the formation of the intermetallic compound Al₁₁La₃. Thermodynamic properties such as Gibbs energy of formation of Al₁₁La₃, excess Gibbs energy and the activity coefficient of La in Al were calculated from the open circuit potential measurement.     

Development of self-healing star metallopolymers by metal–ligand crosslinking

The development of artificial materials with reversible and efficient self-healing property is an emerging and challenging task in intelligent materials science. In this article, we have developed a six-arm star copolymer system consisting of terpyridine moieties as end-chain functionality for the formation of self-healing metallopolymer networks. The star was synthesized using the atom transfer radical polymerization technique and subsequent crosslinking by the addition of iron (II) salts with three different counterions. The resulting materials exhibit promising self-healing performance as compared with a linear polymer system within time intervals of 6–8 h at moderate temperatures of 80–120 °C. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48527.     

Enhanced conversion efficiency of quasi solid state dye sensitized solar cells based on functionalized multi-walled carbon nanotubes incorporated TiO<Subscript>2</Subscript> photoanode

A series of quasi solid state dye sensitized solar cells were fabricated based on the different weight% of MWCNT@TiO₂ photoanode. The MWCNT@TiO₂ nanocomposites were synthesized by simple wet impregation method. The incorporation of MWCNT into the TiO₂ was confirmed by X-ray diffraction, energy dispersive X-ray spectrum and UV–visible spectroscopy. The morphological properties of the nanocomposites were analyzed by transmission electron microscopic analysis. The performance of the quasi solid state dye sensitized solar cell depends solely on the MWCNT content of the photoanode, as the same PVA polymer gel electrolyte has been used. Compared to the conventional TiO₂ photoanode based DSSCs 0.05 wt% MWCNT containing photoanode provide the maximum short circuit current density and the photo conversion efficiency of 9.811 mA/cm^?2 and 3.59 %. The introduction of MWCNT into the TiO₂ results in the rapid electron transport in the photoanode by forming a conductive network due to which improvement in the short circuit current was observed.     

Thermally deposited Ag-doped CdS thin film transistors with high-k rare-earth oxide Nd2O3 as gate dielectric

The performance of thermally deposited CdS thin film transistors doped with Ag has been reported. Ag-doped CdS thin films have been prepared using chemical method. High dielectric constant rare earth oxide Nd₂O₃ has been used as gate insulator. The thin film trasistors are fabricated in coplanar electrode structure on ultrasonically cleaned glass substrates with a channel length of 50 μm. The thin film transistors exhibit a high mobility of 4.3 cm² V^?1 s^?1 and low threshold voltage of 1 V. The ON-OFF ratio of the thin film transistors is found as 10⁵. The TFTs also exhibit good transconductance and gain band-width product of 1.15 × 10^?3 mho and 71 kHz respectively.     

Hastening of leaf senescence in the processing of green tea leaf to black tea

The current system of processing green tea leaf (Camellia sinensis) to produce black tea involves a long period, especially because of the withering process practised in acquiring leaf senescence which is essential to impart fullness to the resulting tea liquors. Hastening leaf senescence by artificial withering at temperatures favourable to enzymic transformations accelerated the process and considerably shortened the manufacture of black teas.     

Contamination-insensitive differential capacitive pressure sensors

In this paper, a contamination-insensitive differential capacitive pressure sensor with a sealed gap is presented. This device is made of three polysilicon layers including a stationary middle plate and the top and bottom plates that are rigidly coupled together by a series of posts hence deflecting in tandem by a change in differential or gauge pressure. Because of the posts, however, the device is insensitive to common-mode pressure. As the differential pressure is changed from -70 to 70 kPa, the capacitance between the bottom and middle plates changes by 73 fF (sensitivity of approximately 0.5 fF/kPa), yet there is only a 2-fF change in output when the common-mode pressure is changed from 30 to 200 kPa. The devices have a linearity error on the order of -15% FSS and a temperature coefficient of offset of 170 ppm/°C     

Elimination of post-release adhesion in microstructures usingconformal fluorocarbon coatings

The adhesion of polysilicon microstructures to their substrates is eliminated using a relatively conformal hydrophobic fluorocarbon (FC) coating grown in a field-free zone of a plasma reactor. Experiments show that the FC film deposition on top of the microstructure and on the underside was approximately 2:1. The FC coating is able to cover the entire underside of a 200×200 μm² plate, with a 20% deposition nonuniformity. The coating exhibits a contact angle of 110° and is able to prevent adhesion of cantilever beams and doubly supported beams to their substrates even after direct immersion in DI water. The durability of the coating was tested using an accelerated aging method, predicting a lifetime of greater than ten years at 150°C. Periodic wear tests indicate that the coating remains hydrophobic even after 10⁷ contact cycles