Flexible and stretchable electrochromic supercapacitor systems are widely considered as promising multifunctional energy storage devices that eliminate the need for an external power source. Nevertheless, the performance of conventional designs deteriorates significantly as a result of electrode/electrolyte exposure to atmosphere as well as mechanical deformations for the case of flexible systems. In this study, we suggest an all-transparent stretchable electrochromic supercapacitor device with ultrastable performance, which consists of Au/Ag core–shell nanowire-embedded polydimethylsiloxane (PDMS), bistacked WO3 nanotube/PEDOT:PSS, and polyacrylamide (PAAm)-based hydrogel electrolyte. Au/Ag core–shell nanowire-embedded PDMS integrated with PAAm-based hydrogel electrolyte prevents Ag oxidation and dehydration while maintaining ionic and electrical conductivity at high voltage even after 16 days of exposure to ambient conditions and under application of mechanical strains in both tensile and bending conditions. WO3 nanotube/PEDOT:PSS bistacked active materials maintain high electrochemical–electrochromic performance even under mechanical deformations. Maximum specific capacitance of 471.0 F g–1 was obtained with a 92.9% capacity retention even after 50 000 charge–discharge cycles. In addition, high coloration efficiency of 83.9 cm2 C–1 was shown to be due to the dual coloration and pseudocapacitor characteristics of the WO3 nanotube and PEDOT:PSS thin layer.

A "Polyol" method has granted low-cost and facile process-controllability for silver-nanowire (Ag-NW) synthesis. Although homogenous and heterogeneous nucleation and growth during Ag-NW synthesis are possible using polyol methods, heterogeneous nucleation and growth of Ag NW guarantees highly selective growth of nanostructures using silver chloride (AgCl) seeds, which provides a stable source of chloride ions (Cl-) and thermodynamic reversibility. In this paper, a microdroplet has been adopted to synthesize uniform AgCl seeds with different diameter that are used for seed-mediated Ag-NW synthesis. The concentration of two precursors (AgNO and NaCl) in the droplets is modulated to produce different sizes of AgCl seeds, which determines the diameter and length of Ag NWs. The process of the seed-mediated growth of Ag NWs has been monitored by observing the peak shift in the time-resolved UV-vis extinction spectrum. Furthermore, the distinct plasmonic property of Ag NWs for transverse and longitudinal localized-surface-plasmon-resonance (LSPR)-mediated fluorescence enhancement is utilized. The high aspect ratio and sharp tips work as simple antennas that induce the enhanced fluorescence emission intensity of a fluorophore, which can be applied in the fields of biological tissue imaging and therapy.

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The two-dimensional (2D) graphene sheets show superior electrical, thermal and mechanical properties. The three-dimensional (3D) graphene assemblies have also recently garnered great attention because of their high surface area, free-standing configuration and facile fabrication of graphene composites with nanomaterials in practical applications. Herein, we demonstrate the synthesis of a variety of 3D graphene assemblies including spheres, twiddles and hemispheres using micro-droplet reactors. Such 3D reduced graphene oxide (rGO) structures can be manipulated by controlling the aggregation pattern of the GO sheet inside the micro-droplets. The aggregation pattern depends on the diffusion rate of the aqueous solution in the droplet. The pattern was simply tuned by the amount of oil phase in the droplet during evaporation. In addition, micro-porous structures were manufactured by incorporating silica beads in the rGO microparticles, followed by a wet etching process. The local plasmonic properties of the 3D porous hemispherical rGO were investigated by electron energy-loss spectroscopy mapping. INTRODUCTIONThe superlative properties of graphene such as exceptional carrier mobility, thermal conductivity and mechanical strength have been demonstrated in a variety of research fields. 1-3 Despite the great potential of graphene as a substitution for state-of-the-art materials, the difficulty of the fabrication processes for graphene, the lack of reliable techniques for integrating graphene into devices and their tendency of aggregation among graphene sheets remain challenges to overcome. [4][5][6][7][8] Contrary to the two-dimensional (2D) graphene sheet, the assembly of the 2D graphene in a controllable way results in unique three-dimensional (3D) graphene materials. The 3D graphene structures show several advantages, such as aggregation resistance, high surface area, easy handling due to free-standing configuration and facile composition of graphene with nanomaterials, while the excellent electronic and mechanical properties were retained. 7,[9][10][11][12] The most popular method to change 2D graphene to a 3D graphene assembly is to use graphene oxide (GO) as an intermediate that can be produced on a large scale and retains high dispersibility in water owing to the oxygenous functional groups. Once the 3D GO structure was fabricated, the chemical or thermal reduction reaction could return the GO into rGO (reduced graphene oxide) whose atomic structure is similar to graphene with some defects. [9][10][11][13][14][15][16] In this context, the fabrication of GO films and crumpled rGO microparticles has been reported. In the case of the GO films, gas bubbles or versatile organic solvents transferred the GO in a bulk solution to the liquid-air interface for assembly. [17][18][19][20][21] Although the synthesis of a large-scale GO