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Cu-C70 nanocomposite thin film is synthesized via thermal co-evaporation method. The atomic concentration of Cu in the thin film is found to be ~4.5 at.% using Rutherford backscattering spectroscopy. Sequential thermal annealing is performed in an inert atmosphere (in presence of Ar) at various temperatures. Surface plasmon resonance (SPR) is spotted at ~585 nm for the sample annealed at 300 °C and the SPR peak is shifted towards ~621 nm for the sample annealed at 400 °C. In order to determine the modifications arising in the structure of fullerene C70 matrix due to annealing, Raman spectroscopy is used. At the highest temperature of 400 °C, the high-intensity Raman active modes of fullerene C70 can still be observed which shows that fullerene C70 is not completely transformed into amorphous carbon upto this temperature. Transmission electron microscopy is performed to determine the size of particles which is obtained ~35 nm for the sample annealed at 400 °C. The red shift in SPR wavelength at 400 °C is ascribed to the growth of Cu nanoparticles.

This paper reports the direct fabrication of ultrathin and conductive thin films of multiwalled carbon nanotube (MWCNT), reduced graphene oxide(r-GO) and r-GO/MWCNT on insulating substrates by dip coating followed by chemical vapour deposition (CVD). The obtained films exhibit conductivity of 136S/cm, 132 S/cm, and 51.2 S/cm respectively. The CVD process not only reduced the GO film, but it also bridges the voids between the individual MWCNT and/or r-GO flakes. The electrochemical performance of MWCNT, r-GO, and r-GO/MWCNT thin films as active supercapacitor electrodes is also evaluated using cyclic voltammetry. The calculated specific capacitance was found to be ≈74 F/g, 65 F/g, and 48 F/g, respectively. The electrochemical performance indicates that these electrodes have large specific capacitance and can be used for several advanced energy storage applications.

The paper reports development of graphene/ZnO heterojunction Schottky diode structure and its structural and electrical characterization. Graphene is grown on copper substrate using chemical vapor deposition (CVD) and transferred on flexible substrate (indium Tin Oxide coated PET). The grown thin layer is characterized using scanning electron microscopy and Raman spectroscopy which confirm uniformity and high-quality graphene layer. The sputtered ZnO is deposited and characterized which confirms c-axis (002) orientation and uniform growth of ZnO film. Silver (Ag) as a top electrode has been deposited and I–V measurement has been done. The effect of operating temperature (300 K to 425 K) on I–V characteristics of the fabricated structure has been measured experimentally. The other diode parameters such as ideality factor and effective barrier height have been derived. The reliability of the heterojunction synthesized is proved by the diode ideality factor of 1.03 attained at 425 K. The excellent C–V characteristics (capacitance of 48pF) of the device prove that the device is an excellent candidate for application as supercapacitors. The fabricated structure can be utilized as an ultraviolet photodetector, solar cell, energy storage devices, etc.

The highest conductivity in graphene oxide based thin film electrodes has been achieved using high temperature annealing at 1100 °C. This is unfavorable for low cost production and application over plastic substrates. Here we report highly conducting graphene thin films using spin coating of a functionalized graphene solution over various substrates. The bridged graphene nanoflakes provide higher conducting pathways in the thin film, enabling electrodes to be fabricated at low temperatures of the order 150 °C. These thin film electrodes show remarkable sheet resistance of the order 0.4 kΩ sq.−1 and transmittance up to 94%. This work demonstrates that graphene based transparent electrodes have the potential to replace existing doped metal oxide based electrodes. The electrochemical performance of graphene thin films as active supercapacitor electrodes was evaluated using cyclic voltammetry. The calculated specific capacitance was found to be ≈49, 48, 48 and 68 F g−1 for the graphene thin film electrodes fabricated at spin speeds of 1000, 1200, 1400 and 1600 rpm, respectively. The above electrochemical performance indicates that the graphene electrodes show large specific capacitance and could be very attractive for several applications including wearable electronics, smart windows and advanced display panels.

Here we report a wet chemical technique to obtain transparent electrodes for optoelectronic devices. This technique is simple, facile, low cost and an effective way to prepare ultrathin free standing hybrid graphene/multiwalled carbon nanotubes (MWCNT) films. The graphene/MWCNT films, up to 36 mm in diameter, with controllable thickness and root mean square surface roughness of the order of 12.6 nm are prepared. The ratio of graphene/MWCNT is optimized to make them free standing and easily transferrable on various substrates. The ratio of direct current conductivity to the optical conductivity (σdc/σopt) which is considered as figure of merit for transparent conductors, is enhanced to 10.27 for graphene/MWCNT hybrid films. The prepared films showed outstanding transmittance up to 87.3 ± 1% at 550 nm, 87.9 ± 1% at 800 nm and sheet resistance of 136 ± 22.4 Ω/sq.

Sensing of urea is the key component in the diagnosis of kidney related diseases and milk adulteration. Until now, the methods developed for urea sensing are not easy to perform, and very little attention has been paid to commercialization of such sensors. Herein, for the first time we report the low cost graphene nanoplatelets (GNPlts) based sensing platform for urea. Specifically edge functionalized GNPlts are used for keeping graphitic activity of graphene planes intact. We have successfully sensed variable ranges of urea concentrations from 0.1–0.8 mg ml−1. The amperometeric characterization showed a linear variation in current as a function of urea concentration. The developed platform has a rapid response time of 15 s with good sensitivity (33 μA (mg ml−1)−1) and specificity. This developed nanoplatform could be highly beneficial for the development of an ultrasensitive, disposable, routine use sensor for urea.

The technical and economic growth of the twentieth century was marked by evolution of electronic devices and gadgets. The day-to-day lifestyle has been significantly affected by the advancement in communication systems, information systems and consumer electronics. The lifeline of progress has been the invention of the transistor and its dynamic up-gradation. Discovery of fabricating Integrated Circuits (IC’s) revolutionized the concept of electronic circuits. With advent of time the size of components decreased, which led to increase in component density. This trend of decreasing device size and denser integrated circuits is being limited by the current lithography techniques. Non-uniformity of doping, quantum mechanical tunneling of electrons from source to drain and leakage of electrons through gate oxide limit scaling down of devices. Heat dissipation and capacitive coupling between circuit components becomes significant with decreasing size of the components. Along with the intrinsic technical limitations, downscaling of devices to nanometer sizes leads to a change in the physical mechanisms controlling the charge propagation. To deal with this constraint, the search is on to look around for alternative materials for electronic device application and new methods for electronic device fabrication. Such material is comprised of organic molecules, proteins, carbon materials, DNA and the list is endless which can be grown in the laboratory. Many molecules show interesting electronic properties, which make them probable candidates for electronic device applications. The challenge is to interpret their electronic properties at nanoscale so as to exploit them for use in new generation electronic devices. Need to trim downsize and have a higher component density have ushered us into an era of nanoelectronics.

Various biomedical applications of nanomaterials have been proposed in the last few years leading to the emergence of a new field in diagnostics and therapeutics. Most of these applications involve the administration of nanoparticles into patients. Carbon Nanotubes are enjoying increasing popularity as building blocks for novel drug delivery systems as well as for bioimaging and biosensing. The recent strategies to functionalize carbon nanotubes have resulted in the generation of biocompatible and water-soluble carbon nanotubes that are well suited for high treatment efficacy and minimum side effects for future cancer therapies with low drug doses. The toxicological profile of such carbon nanotube systems developed as nanomedicines will have to be determined prior to any clinical studies undertaken.

Graphene, an atom–thick two dimensional graphitic material have led various fundamental breakthroughs in the field of science and technology. Due to their exceptional optical, physical and electrical properties, graphene based transparent electrodes have shown several applications in organic light emitting diodes, solar cells and thin film transistors. Here, we are presenting effect of annealing over optoelectronic properties of graphene based transparent electrodes. Graphene based transparent electrodes have been prepared by wet chemical approach over glass substrates. After fabrication, these electrodes tested for optical transmittance in visible region. Sheet resistance was measured using four probe method. Effect of thermal annealing at 200 °C was studied over optical and electrical performance of these electrodes. Optoelectronic performance was judged from ratio of direct current conductivity to optical conductivity (σdc/σopt) as a figure of merit for transparent conductors. The fabricated electrodes...

Organic solvents and surfactants both are used to disperse Carbon Nanotubes (CNTs), but the efficiency of both are different. Surfactant much efficiently disperse CNTs in comparison to organic solvent. As opposed to aqueous solutions, hydrophobic Single Wall Nanotubes (SWNTs) are easily wetted by organic solvent Di-Methyl Formamide (DMF) and therefore, to reduce self assembling of bundles and ropes of CNTs. Surfactants are effective at concentration 1 wt % for dispersion of SWNTs. Sodium Dodecyl Benzene Sulfonate (SDBS) effectively disperse aqueous solution of SWNTs at 0.5 mg/ml and further solution is diluted to concentration 0.3 mg/ml. Probe type sonication is used to make homogeneous solution and for initial exfoliation of CNTs. Small bundles and single SWNTs can be separated from bundles and amorphous carbon by using centrifugation. Atomic Force Microscopy (AFM) is employed to image the dispersed state of SWNTs by using organic solvent and aqueous solution of surfactant. Graphene presence and density difference of these are also observed at different concentration of SWNTs.

We have reported a simple, scalable and solution processed graphene patterning method using electron beam lithography followed by a lift-off process. This method is free from etching process and can be used for fabrication of graphene based patterns for nanodevices application. This process is universal to arbitrary substrates and can be employed for large scale pattern fabrication especially for graphene array based nanodevice applications. Using this method various types of graphene patterns like rectangular lines (100 μm × 10 μm) connecting with square pads (50 μm × 50 μm) and hall probe patterns were created over oxidized silicon substrates.