Abstract: Graphene electrodes-based supercapacitors are in demand due to superior electrochemical characteristics. However, commercial applications have been limited by inferior electrode cycle life. A method to fabricate highly efficient supercapacitor electrodes using pristine graphene sheets vertically-stacked and electrically connected to the carbon fibers which results in vertically-aligned graphene-carbon fiber nanostructure is disclosed. The vertically-aligned graphene-carbon fiber electrode prepared by electrophoretic deposition possesses a mesoporous three-dimensional architecture which enabled faster and efficient electrolyte-ion diffusion with a specific capacitance of 333.3 F g?1. The electrodes have electrochemical cycling stability of more than 100,000 cycles with 100% capacitance retention. Apart from the electrochemical double layer charge storage, the oxygen-containing surface moieties and ?-Ni(OH)2 present on the graphene sheets enhance the charge storage by faradaic reactions.

Abstract: A dual-function supercapacitor carbon fiber composite stores electrical energy and functions, for example, as the body shell of electric vehicles (EVs). This is achieved with a vertically aligned graphene on carbon fiber electrode, upon which metal oxides were deposited to obtain ultra-high energy density anode and cathode. A high-strength multilayer carbon composite assembly is fabricated using an alternate layer patterning configuration of epoxy and polyacrylamide gel electrolyte. The energized composite delivers a high areal energy density of 0.31 mWh cm?2 at 0.3 mm thickness and showed a high tensile strength of 518 MPa, bending strength of 477 MPa, and impact strength 2666 J/m. To show application in EVs, a toy car body fabricated with energized composite operates using the energy stored inside the frame. Moreover, when integrated with a solar cell, this composite powered an IoT (interne of things) device, showing feasibility in communication satellites.

Abstract: A phototransistor device to act as an artificial photonic synapse includes a substrate and a graphene source-drain channel patterned on the substrate. A perovskite quantum dot layer is formed on the graphene source-drain channel. The perovskite quantum dot layer is methylammonium lead bromide material. A method of operating the phototransistor device as an artificial photonic synapse includes applying a first fixed voltage to a gate of the phototransistor and a second fixed voltage across the graphene source-drain channel. A presynaptic signal is applied as stimuli across the graphene source-drain channel. The presynaptic signal includes one or more pulses of light or electrical voltage. A current across the graphene source-drain channel is measured to represent a postsynaptic signal.

Abstract: One type of plasmonic organic electrochemical transistor (POECT) includes a channel comprising an organic semiconductor, a gate electrode comprising at least one of: an ensemble of nanoparticles and an array of nanostructures, wherein each of the at least one of: an ensemble of nanoparticles and an array of nanostructures comprises localized plasmonic material, an analyte formed at least one of: (a) over the at least one of: the ensemble of nanoparticles and the array of nanostructures and (b) around the at least one of: the ensemble of nanoparticles and the array of nanostructures, wherein an electrolyte is configured to be formed at least one of: between the channel and the gate electrode and over the channel and the gate electrode, a source electrode electrically connected to a first end of the channel; and a drain electrode electrically connected to a second end of the channel which is opposite the first end.

Abstract: Energized composites include vertically aligned graphene on carbon fibers (VGCF). The VGCF enhances surface area available for charge storage, acts as templates for depositing other charge storing materials and provides stability for a minimum of 100,000 discharge cycles. The final storage device is in the order of high strength carbon fiber matrix with active material, glass fiber separator with polymer electrolyte and another carbon fiber matrix with active material. To achieve higher voltage or current, devices can be connected in series or parallel, respectively. The whole structure is made into a structural component by infusing epoxy resin. An alternating pattern of energy storage devices allows for the epoxy resin to seep through the whole structure and strongly bind them to make a monolith multifunctional composite.

Abstract: Techniques for growing, at least one of: (a) quantum dots and (b) nano-crystals, on a surface of a material are provided. One method comprises placing a precursor on the surface; adding an antisolvent to the precursor; and growing at least one of the quantum dots and the nanocrystals on the surface.

Abstract: A photodetector device to act as an artificial photonic synapse includes a substrate and a perovskite quantum dot-multiwall carbon nanotube (PQD-MWCNT) hybrid material. The PQD-MWCNT hybrid material channel is disposed on the substrate between a first electrode and a second electrode and forms a PQD-MWCNT channel. The PDQs comprise a methylammonium lead bromide material. A method of operating the photodetector device as an artificial photonic synapse includes applying a presynaptic signal as stimuli as one or more light pulses on the PQD-MWCNT channel between the first electrode and the second electrode. A current across the PQD-MWCNT channel is measured to represent a postsynaptic signal.

Abstract: Described are interdigitated electrodes, which may optionally be plasmonic, useful for in vitro biosensing applications. Such devices may significantly reduce undesired background noise by separating the excitation source (light) from the detection signal (current), and thereby, leading to higher sensitivity for bioanalysis compared with conventional interdigitated electrodes. Also described are methods of making such interdigitated electrodes, which allow a substrate, which may optionally be plasmonic, to be tuned not only to maximize the targeted interaction of the cells with the nanoscale geometry, but also for the excitation wavelength to minimize biological sample interference.

Abstract: Techniques for growing, at least one of: (a) quantum dots and (b) nano-crystals, on a surface of a material are provided. One method comprises placing a precursor on the surface; adding an antisolvent to the precursor; and growing at least one of the quantum dots and the nanocrystals on the surface.

Abstract: An integrated energy harvesting and storage device (IEHSD) includes a solar cell (SC) including an active layer between an optically transparent top electrode and a bottom electrode, and an energy storage device (SD) secured below the solar cell including a separator between a first electrode and a second electrode. The bottom electrode and the first or second electrode are electrically common with one another and are within a distance of ?300 ?m from one another.

Abstract: Graphene electrodes-based supercapacitors are in demand due to superior electrochemical characteristics. However, commercial applications have been limited by inferior electrode cycle life. A method to fabricate highly efficient supercapacitor electrodes using pristine graphene sheets vertically-stacked and electrically connected to the carbon fibers which results in vertically-aligned graphene-carbon fiber nanostructure is disclosed. The vertically-aligned graphene-carbon fiber electrode prepared by electrophoretic deposition possesses a mesoporous three-dimensional architecture which enabled faster and efficient electrolyte-ion diffusion with a specific capacitance of 333.3 F g?1. The electrodes have electrochemical cycling stability of more than 100,000 cycles with 100% capacitance retention. Apart from the electrochemical double layer charge storage, the oxygen-containing surface moieties and ?-Ni(OH)2 present on the graphene sheets enhance the charge storage by faradaic reactions.

Abstract: A phototransistor device to act as an artificial photonic synapse includes a substrate and a graphene source-drain channel patterned on the substrate. A perovskite quantum dot layer is formed on the graphene source-drain channel. The perovskite quantum dot layer is methylammonium lead bromide material. A method of operating the phototransistor device as an artificial photonic synapse includes applying a first fixed voltage to a gate of the phototransistor and a second fixed voltage across the graphene source-drain channel. A presynaptic signal is applied as stimuli across the graphene source-drain channel. The presynaptic signal includes one or more pulses of light or electrical voltage. A current across the graphene source-drain channel is measured to represent a postsynaptic signal.

Abstract: Techniques for growing, at least one of: (a) quantum dots and (b) nano-crystals, on a surface of a material are provided. One method comprises placing a precursor on the surface; adding an antisolvent to the precursor; and growing at least one of the quantum dots and the nanocrystals on the surface.

Abstract: A method for the fabrication of h-WO3/WS2 core/shell nanowires and their use in flexible supercapacitor applications. The novel nanowire assemblies exhibit multifold advantages desired for high-performance supercapacitors, including superior material properties and electrode design. The material design principle can be extended to other material systems, implying its great potential for a variety of energy storage devices compatible with emerging flexible and wearable technologies.

Abstract: Described are interdigitated electrodes, which may optionally be plasmonic, useful for in vitro biosensing applications. Such devices may significantly reduce undesired background noise by separating the excitation source (light) from the detection signal (current), and thereby, leading to higher sensitivity for bioanalysis compared with conventional interdigitated electrodes. Also described are methods of making such interdigitated electrodes, which allow a substrate, which may optionally be plasmonic, to be tuned not only to maximize the targeted interaction of the cells with the nanoscale geometry, but also for the excitation wavelength to minimize biological sample interference.

Abstract: An integrated energy harvesting and storage device (IEHSD) includes a solar cell (SC) including an active layer between an optically transparent top electrode and a bottom electrode, and an energy storage device (SD) secured below the solar cell including a separator between a first electrode and a second electrode. The bottom electrode and the first or second electrode are electrically common with one another and are within a distance of ?300 ?m from one another.

Abstract: A method for the fabrication of h-WO3/WS2 core/shell nanowires and their use in flexible supercapacitor applications. The novel nanowire assemblies exhibit multifold advantages desired for high-performance supercapacitors, including superior material properties and electrode design. The material design principle can be extended to other material systems, implying its great potential for a variety of energy storage devices compatible with emerging flexible and wearable technologies.

Abstract: In an exemplary method, a nano-architectured carbon structure is fabricated by forming a unit (e.g., a film) of a liquid carbon-containing starting material and at least one dopant. A surface of the unit is nano-molded using a durable mold that is pre-formed with a pattern of nano-concavities corresponding to a desired pattern of nano-features to be formed by the mold on the surface of the unit. After nano-molding the surface of the unit, the first unit is stabilized to render the unit and its formed nano-structures capable of surviving downstream steps. The mold is removed from the first surface to form a nano-molded surface of a carbonization precursor. The precursor is carbonized in an inert-gas atmosphere at a suitable high temperature to form a corresponding nano-architectured carbon structure. A principal use of the nano-architectured carbon structure is a carbon electrode used in, e.g., Li-ion batteries, supercapacitors, and battery-supercapacitor hybrid devices.

Abstract: In an exemplary method, a nano-architectured carbon structure is fabricated by forming a unit (e.g., a film) of a liquid carbon-containing starting material and at least one dopant. A surface of the unit is nano-molded using a durable mold that is pre-formed with a pattern of nano-concavities corresponding to a desired pattern of nano-features to be formed by the mold on the surface of the unit. After nano-molding the surface of the unit, the first unit is stabilized to render the unit and its formed nano-structures capable of surviving downstream steps. The mold is removed from the first surface to form a nano-molded surface of a carbonization precursor. The precursor is carbonized in an inert-gas atmosphere at a suitable high temperature to form a corresponding nano-architectured carbon structure. A principal use of the nano-architectured carbon structure is a carbon electrode used in, e.g., Li-ion batteries, supercapacitors, and battery-supercapacitor hybrid devices.

Abstract: A photorefractive (PR) polymer composite (310) is provided that includes a charge transporting polymer (CTP) matrix (311) and a photosensitizer (312) comprising a quantum dot (QD) material (314) with a first band gap (315) coupled to a nanoparticle material (317) with a second band gap (316) greater than the first band gap. The photosensitizer (312) is configured to generate a plurality of free charges (318) and to transfer the free charges to the CTP matrix (311) in response to an incident photon (320) on the PR polymer composite (310). An apparatus (500) is also provided, for writing holograms of 3D perspective views of an object from different directions within the PR polymer composite (310). A method (600) is also provided for forming the PR polymer composite.