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Stretchable electronics (i.e., Elastronics) are essential to the realization of next‐generation wearable bioelectronics for personalized medicine, due to their unique skin‐conformal features ideal for seamless integration with the human body. Significant progress has been made to nanowire‐based elastronics with promising applications ranging from electronic‐skin to advanced energy harvest systems. However, it remains a key challenge to rationally control over the nanowire morphology and configurations to achieve desired multifunctionality. Herein, a stretchable jellyfish‐like gold nanowires film with high conductivity and stretchability is presented by using gold nanostar‐seeded nanowire growth method. They exhibit unique hierarchically oriented structure with gold nanostars as the multi‐branched active sites (top layer) and vertically intertwined nanowires (bottom layer) trailing below the nanostars. Such nanowires film can be stretched up to 200% with a retaining low normalized resistance of 13.8 due to the unique hierarchical structure. Furthermore, the film can be used as stretchable supercapacitor with a 92% capacitance retention and superior durability even after 5000 electrochemical scanning cycles. The method is general, which can be further expanded to other metallic seeds, hence, representing a low‐cost yet efficient strategy for the fabrication of stretchable elastronics and robust energy storage devices for on‐body biosensing and bioelectronics. [ABSTRACT FROM AUTHOR]

Here, a black Au surface is presented: a material solely composed of Au that is capable of absorbing more than 92% of the incident light over a spectral region ranging from 300 to 600 nm and that can maintain a high absorbance (above 70%) for wavelengths up to 800 nm. The black Au surface is fabricated by a simple and scalable template-assisted physical vapor deposition technique and possesses the flexibility of adhering to any arbitrary substrate. The high absorbance of Au originates from the close packing of high aspect ratio Au nanotubes possessing a random tapered wall thickness. Fabry-Perot resonances of gap-plasmon modes between the Au nanotubes are also responsible for the strong suppression of reflectance of black Au as demonstrated by finite element method simulations. Furthermore, the ability of this surface to drive photochemical transformations under visible light illumination is demonstrated. Hence, black Au could provide a new paradigm for the use of highly absorbing metal nanostructures to effectively harvest the entire visible spectrum for photorelated applications such as solar fuel production, photodetection, and photovoltaics. [ABSTRACT FROM AUTHOR]

Free‐standing 2D nanoassemblies are ultrathin nanomembranes or nanosheets constructed from constituent nanoscale building blocks including metal nanoparticles, quantum dots, and magnetic nanoparticles, typically by a bottom‐up self‐assembly approach. Such free‐standing nanoassemblies are a new class of advanced functional materials that can integrate the unique optoelectronic properties of nanomaterials with thin film mechanics into confined 2D space. This offers attributes such as minimizing substrate effects, facile transfer, and soft devices in comparison to the corresponding substrate‐supported system. This review covers the recent progress in fabrication, characterization, and application of the free‐standing 2D nanoassemblies. To begin with, the attributes of free‐standing 2D nanoassemblies are discussed, followed by the description of fabrication methodologies. Then their novel optical, electronic, mechanical, magnetic, and stimuli responsible properties are covered, and their potential applications in filtration membrane, nanomechanical devices, and chemical sensing are further discussed. Finally, perspectives on the challenges and future opportunities of the free‐standing 2D nanoassemblies are shared. [ABSTRACT FROM AUTHOR]