Semiconductor Nanoparticle Anchored Single-Walled Carbon Nanotubes for a Bolometer.

The bolometer is developed using single-walled carbon nanotubes (SWCNT) anchored with semiconductor nanoparticles of cadmium sulfide, stannous disulfide, and zinc oxide (ZnO). The bolometric responses were recorded at varying temperatures from 10 K to room temperature. The anchored SWCNTs provided a higher temperature coefficient of resistance (TCR) than pristine SWCNTs.

Ultrahigh Photo-Responsivity and Detectivity in 2D Bismuth Sulfide Photodetector for Vis-NIR Radiation.

Bismuth sulfide (BiS) exhibits a direct energy bandgap and an exceptional optical absorption capability over a broadband radiation, thus presents a novel class of 2D photodetector material. The field effect transistor (FET) photodetector device is fabricated from 2D BiS. An anomalous variation in the transport characteristics of 2D BiS is observed with the variation in temperature.

Three-dimensional carbon foam-metal oxide-based asymmetric electrodes for high-performance solid-state micro-supercapacitors.

A three-dimensional carbon foam (CF)-based asymmetric planar micro-supercapacitor is fabricated by the direct spray patterning of active materials on an array of interdigital electrodes. The solid-state asymmetric micro-supercapacitor comprises the CF network with pseudocapacitive metal oxides (manganese oxide (MnO), iron oxide (FeO)), where CF-MnO composite as a positive electrode, and CF-FeO as negative electrode for superior electrochemical performance. The micro-supercapacitor, CF-MnO//CF-FeO, attains an ultrahigh supercapacitance of 18.

Novel electrode geometry for high performance CF/FeO based planar solid state micro-electrochemical capacitors.

A novel geometry of sharp-edged electrodes for planar micro-electrochemical capacitors is utilized for an enhanced performance compared to the conventionally used interdigitated electrodes. The sharp-edged electrode geometry achieves a 68% enhancement in the electric field at the sharp-edge of the electrodes as compared to interdigitated electrodes. Moreover, carbon foam with high specific surface area loaded with iron oxide nanoparticles allows a large mass loading for the pseudocapacitance in addition to electric double layer capacitance (EDLC).

Tailored viscoelasticity of a polymer cellular structure through nanoscale entanglement of carbon nanotubes.

A three-dimensional carbon nanotube (CNT) cellular structure presents a unique revelation of microstructure dependent mechanical and viscoelastic properties. Tailored CNT-CNT entanglement demonstrated a direct impact on both the strength and viscosity of the structure. Unlike traditional foams, an increase in the CNT-CNT entanglement progressively increases both the strength and the viscosity.

Deterministic Role of Carbon Nanotube-Substrate Coupling for Ultrahigh Actuation in Bilayer Electrothermal Actuators.

Here, the actuation response of an architectured electrothermal actuator comprising a single layer of carbon nanotube (CNT) film and a relatively thicker film of silk, cellulose, or polydimethylsiloxane is studied. An electric current is passed through the CNT film, which generates heat responsible for electrothermal actuation, in all samples, affixed as per doubly clamped beam configuration. All samples, including pure CNT film, show remarkable actuation such that actuation monotonically increases with the applied voltage.

Spray Coating of Two-Dimensional Suspended Film of Vanadium Oxide-Coated Carbon Nanotubes for Fabrication of a Large Volume Infrared Bolometer.

A novel spray coating and transfer method is developed for fabricating a suspended bolometer of vanadium oxide-coated multiwalled carbon nanotubes (VCNTs). A parametric study was performed to evaluate the effect of the substrate, modulation frequency, and temperature on the bolometric performance and revealed that the performance of the bolometer solely does not depend on the substrate parameter but modulation frequency and bias current as a function of temperature also play a key attribute. The TCR (temperature coefficient of resistance) of the suspended VCNT bolometer is ∼-0.

Flexible Array of Microsupercapacitor for Additive Energy Storage Performance Over a Large Area.

An on-chip microsupercapacitor (MSC) pattern is obtained by layer-by-layer spray deposition of both manganese dioxide (MnO) nanoparticle-coated carbon nanotubes (MnO-CNTs) and MnO nanosheet-decorated reduced graphene oxide (MnO-rGO) on mechanically robust, flexible polyethylene terephthalate. Layer-by-layer patterning of MSC electrodes offers rapid in-plane diffusion of electrolyte ions in electrodes the layered electrode and hence ultrahigh capacitance and energy density of 7.43 mF/cm (32300 mF/cm) and 0.

Zn induced molecular responses associated with oxidative stress, DNA damage and histopathological lesions in liver and kidney of the fish, Channa punctatus (Bloch, 1793).

Zn is essential for normal physiological functioning of all organisms in small quantities, but when its concentration enhances in surrounding environment it acts as a toxicant to organisms. Common sources of Zn pollution are electroplating, alloying, mining, and allied industrial operations. The present study aims to assess the biochemical, histopathological and genotoxicological implications under Zn intoxication along with its accumulation patterns in prime biotransformation sites-liver and kidney, of a bottom feeder fish, Channa punctatus.

Capacitive behavior of carbon nanotube thin film induced by deformed ZnO microspheres.

Multiwalled carbon nanotubes (CNTs) are uniformly distributed with piezoelectric microspheres. This leads to a large strain gradient due to an induced capacitive response, providing a 250% enhancement in electromechanical response compared with pristine CNTs. The fabricated large-area flexible thin film exhibits excellent pressure sensitivity, which can even detect an arterial pulse with a much faster response time (∼79 ms) in a bendable configuration.

Synergistic effect in the heterostructure of ZnCoO and hydrogenated zinc oxide nanorods for high capacitive response.

Herein, a novel heterostructure was fabricated by combining electrochemically and optically active materials to achieve a high capacitive response of 896 F g at 5 A g. A network of ZnCoO nanorods (NRs) was directly grown on a three-dimensional matrix of H : ZnO NRs (ZnCoO/H : ZnO NRs) that offered synergistic advantages by providing an optimum ion/charge transportation path, large electrochemically active surface area, and stable capacitive response during the electrolytic process. Furthermore, the fabricated solid-state asymmetric supercapacitor ZnCoO/H : ZnO NRs//activated carbon induced a large potential window of 1.

Surface photo-charge effect in doped-ZnO nanorods for high-performance self-powered ultraviolet photodetectors.

The unique photo-charge characteristics of chlorine-doped zinc oxide nanorods (Cl-ZnO NRs) are explored for the first time in ultraviolet (UV) photodetector (PD) that offers an outstanding self-powered photoresponse towards low UV illumination signals. A self-powered Cl-ZnO NRs PD exhibits superior photon detection speed of the order of a few ms with high sensitivity and photoelasticity. Therefore, the presented PD opens up a novel route to fabricate highly efficient self-powered PDs on a large scale without employing complex multilayer systems.

Influence of charge traps in carbon nanodots on gas interaction.

The nonlinear electrical characteristic of carbon nanodots (CNDs) has revealed important physical phenomena of charge trapping playing a dominant role in surface interactions. Functional groups on the surface of CNDs attract ambient water molecules which in turn act as charge traps and give rise to electrical hysteresis that plays a dominant role in understanding charge transport in CNDs on surface interactions. Hysteresis in the current-voltage response is further utilized to study the interaction of the CNDs with nitrogen dioxide gas as an external stimuli.

Conjugated assembly of colloidal zinc oxide quantum dots and multiwalled carbon nanotubes for an excellent photosensitive ultraviolet photodetector.

Conjugation of highly dense colloidal zinc oxide quantum dots (ZnO QDs) on multiwalled carbon nanotubes (ZnO QDs@MWCNTs) is achieved for high performance ultraviolet (UV) photodetection. Significant improvement in the photoresponse of the ZnO QDs@MWCNTs photodetector (PD) is established as compared to a pristine ZnO QDs PD. The conjugation of two constituents allows the direct transfer of photoinduced charge carriers in ZnO QDs to MWCNTs for an efficient electrical path that considerably reduces charge recombination during UV exposure.

Energy-Efficient Hydrogenated Zinc Oxide Nanoflakes for High-Performance Self-Powered Ultraviolet Photodetector.

Light absorption efficiency and doping induced charge carrier density play a vital role in self-powered optoelectronic devices. Unique vanadium-doped zinc oxide nanoflake array (VZnO NFs) is fabricated for self-powered ultraviolet (UV) photodetection. The light harvesting efficiency drastically improved from 84% in ZnO NRs to 98% in VZnO NFs.

Sandwiched assembly of ZnO nanowires between graphene layers for a self-powered and fast responsive ultraviolet photodetector.

A heterostructure of graphene and zinc oxide (ZnO) nanowires (NWs) is fabricated by sandwiching an array of ZnO NWs between two graphene layers for an ultraviolet (UV) photodetector. This unique structure allows NWs to be in direct contact with the graphene layers, minimizing the effect of the substrate or metal electrodes. In this device, graphene layers act as highly conducting electrodes with a high mobility of the generated charge carriers.

Effect of Magnetic Field on Photoresponse of Cobalt Integrated Zinc Oxide Nanorods.

Cobalt integrated zinc oxide nanorod (Co-ZnO NR) array is presented as a novel heterostructure for ultraviolet (UV) photodetector (PD). Defect states in Co-ZnO NRs surface induces an enhancement in photocurrent as compared to pristine ZnO NRs PD. Presented Co-ZnO NRs PD is highly sensitive to external magnetic field that demonstrated 185.

Photoresponse of double-stacked graphene to Infrared radiation.

We report the photoresponse of stacked graphene layers towards infrared radiation. Graphene is stacked in two configurations, namely, crossed and parallel layers. Raman analysis demonstrated a strong interaction among the stacked graphene layers.

Few-layer graphene/ZnO nanowires based high performance UV photodetector.

A graphene and zinc oxide nanowires (G/ZnO NWs) based ultraviolet (UV) photodetector presents excellent responsivity and photocurrent gain with detectivity. Graphene due to higher charge carrier transport mobility induces faster response to UV illumination at the interface between ZnO and graphene with improved response and decay times as compared to a ZnO NWs device alone. A linear increase is revealed for both the responsivity and photocurrent gain of the G/ZnO NWs device with the applied bias.

Highly Dense ZnO Nanowires Grown on Graphene Foam for Ultraviolet Photodetection.

Growth of highly dense ZnO nanowires (ZnO NWs) is demonstrated on three-dimensional graphene foam (GF) using resistive thermal evaporation technique. Photoresponse of the as-grown hybrid structure of ZnO NWs on GF (ZnO NWs/GF) is evaluated for ultraviolet (UV) detection. Excellent photoresponse with fast response and recovery times of 9.

Graphene based multifunctional flame sensor.

Recently, graphene has attracted much attention due to its unique electrical and thermal properties along with its high surface area, and hence presents an ideal sensing material. We report a novel configuration of a graphene based flame sensor by exploiting the response of few layer graphene to a flame along two different directions, where flame detection results from a difference in heat transfer mechanisms. A complete sensor module was developed with a signal conditioning circuit that compensates for any drift in the baseline of the sensor, along with a flame detection algorithm implemented in a microcontroller to detect the flame.

Tailoring viscoelastic response of carbon nanotubes cellular structure using electric field.

Cellular structures of carbon nanotubes (CNT) are novel engineering materials, which are finding applications due to their remarkable structural and functional properties. Here, we report the effects of electric field, one of the most frequently used stimulants for harnessing the functional properties of CNT, on the viscoelastic response, an important design consideration for the structural applications of a cellular CNT sample. The application of an electric field results in electrostriction induced large actuation in freestanding CNT samples; however, if the CNT are prohibited to expand, an electric field dependent force is exerted by the sample on the constraining platens.

Enhanced photoresponse in monolayer hydrogenated graphene photodetector.

We report the photoresponse of a hydrogenated graphene (H-graphene)-based infrared (IR) photodetector that is 4 times higher than that of pristine graphene. An enhanced photoresponse in H-graphene is attributed to the longer photoinduced carrier lifetime and hence a higher internal quantum efficiency of the device. Moreover, a variation in the angle of incidence of IR radiation demonstrated a nonlinear photoresponse of the detector, which can be attributed to the photon drag effect.

Nonlinear optical absorption in a graphene infrared photodetector.

The photoresponse of the graphene photodetector elucidated strong dependence on several optical parameters, such as the angle of incidence and the incident power of infrared exposure at room temperature. The sinusoidal dependence of the photoresponse on incidence angle, which had not been realized before, has now been revealed. The combined effect of the photo excited charge carrier and the photon drag effect explain this nonlinear optical absorption in graphene at lower incident power.