We explore color switching properties of thin polyaniline (PANI) films deposited on plasmonic nanomesh structures in comparison with the films deposited on flat gold. The nanostructured systems show a much steeper color switching with increasing voltage than the films prepared on flat substrates. A strong difference between nanostructured and flat systems is also observed at small voltages, where nanostructured samples often demonstrate an additional feature in cyclic voltammetry curves and nonmonotonous changes in optical properties. Possible origins of the observed effects are discussed in terms of acceleration of charge transport in nanostructured plasmonic environment and interface-related effects. The results can provide opportunities for enhancing and controlling the electrochromic polymer performance in smart windows or display applications.

The ultimate goal of supercapacitor research industries is to develop devices which could be used as flexible, portable, ultrathin and highly-efficient power sources. However, the bulk NiCo 2 O 4 materials prevent the achievement of high energy density as well as immense rate performance due to the limited electroactive surface area. In this work, we proposed a new breakthrough strategy to develop highly porous hierarchical flexible nanosheets of NiCo 2 O 4 -graphene oxide (NiCo 2 O 4 -GO) on nickel foam by a facile electrochemical deposition method. The morphogenesis of the NiCo 2 O 4 -GO hybrid nanostructurebased electrode exhibits hierarchical porous flexible nanosheet-like structures. The electrochemical properties of these electrodes were investigated by cyclic voltammetry and galvanostatic charge-discharge measurements in 3 M KOH electrolyte. The obtained results exhibit that this new hybrid nanostructure has a specific capacitance of 1078 F g À1 at a discharge current of 1 mA with great cyclic stability. These excellent capacitive performances of NiCo 2 O 4 -GO can be attributed to its hierarchical porous nanosheet-like unique structure. This unique structure provides efficient ion transport that is highly desirable for superior rate capability and excellent cycling stability. Hence, our method provides a promising facile and binder-free nanostructure electrode for next generation high-performance supercapacitor applications.

Lesotho Southern AfricaWe report optimization of the synthesis parameters viz. heating temperature (T H ), and hold time (t hold ) for vacuum (10 -5 torr) annealed and LN 2 (liquid nitrogen) quenched MgB 2 compound.These are single-phase compounds crystallizing in the hexagonal structure (space group P 6 /mmm) at room temperature. Our XRD results indicated that for phase-pure MgB 2 , the T H for 10 -5 torr annealed and LN 2 quenched samples is 750 0 C. The right stoichiometry i.e., MgB 2 of the compound corresponding to 10 -5 Torr and T H of 750 0 C is found for the hold time (t hold ) of 2.30 hours. With varying t hold from 1-4 hours at fixed T H (750 0 C) and vacuum (10 -5 torr), the c-lattice parameter decreases first and later increases with t hold (hours) before a near saturation, while the alattice parameter first increase and later decreases beyond t hold of 2.30 hours. c/a ratio versus t hold plot showed an inverted bell shape curve, touching the lowest value of 1.141 which is reported value for perfect stoichiometry of MgB 2 . The optimized stoichimetric MgB 2 compound exhibited superconductivity at 39.2 K with transition width of 0.6 K. In conclusion, the synthesis parameters for phase pure stoichimetric vacuum annealed MgB 2 compound are optimized and are compared with widely reported Ta tube encapsulated samples.

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Possible modifications in electrochemical reaction kinetics are explored in a nanostructured plasmonic environment with and without additional light illumination using a cyclic voltammetry (CV) method. In nanostructured gold, the effect of light on anodic and cathodic currents is much pronounced than that in a flat system. The electron-transfer rate shows a 3-fold increase under photoexcitation. The findings indicate a possibility of using plasmonic excitations for controlling electrochemical reactions.