Despite the recent developments in graphene oxide due to its importance as a host precursor of graphene, the detailed electronic structure and its evolution during the thermal reduction remain ...largely unknown, hindering its potential applications. We show that a combination of high-resolution in situ X-ray photoemission and X-ray absorption spectroscopies offer a powerful approach to monitor the deoxygenation process and comprehensively evaluate the electronic structure of graphene oxide thin films at different stages of the thermal reduction process. It is established that the edge plane carboxyl groups are highly unstable, whereas carbonyl groups are more difficult to remove. The results consistently support the formation of phenol groups through reaction of basal plane epoxide groups with adjacent hydroxyl groups at moderate degrees of thermal activation (∼400 °C). The phenol groups are predominant over carbonyl groups and survive even at a temperature of 1000 °C. For the first time, a drastic increase in the density of states (DOS) near the Fermi level at 600 °C is observed, suggesting a progressive restoration of aromatic structure in the thermally reduced graphene oxide.
Reduced graphene oxide/platinum supported electrocatalysts (Pt/RGO) were synthesized by employing a fast and eco-friendly microwave-assisted polyol process, which facilitated the simultaneous ...reduction of graphene oxide and formation of Pt nanocrystals. This system was tested for potential use as an anode material through the electrooxidation of methanol. Compared to the commercial carbon-supported Pt electrocatalysts, the Pt/RGO showed an unprecedented CO poisoning tolerance, high electrochemical active surface area, and high catalytic mass activity for methanol oxidation reaction, demonstrated by increases of 110, 134, and 60%, respectively. We found that the high concentration of oxygen functional groups on reduced graphene oxide plays a major role on the removal of carbonaceous species on the adjacent Pt sites, underlining a synergetic effect between the oxygen moieties on graphene support and Pt nanoparticles. The present microwave assisted synthesis of Pt/RGO provides a new path to prepare electrocatalysts with excellent electrocatalytic activity and CO tolerance, which is of great significance in energy-related applications.
Flexible supercapacitors, a state‐of‐the‐art material, have emerged with the potential to enable major advances in for cutting‐edge electronic applications. Flexible supercapacitors are governed by ...the fundamentals standard for the conventional capacitors but provide high flexibility, high charge storage and low resistance of electro active materials to achieve high capacitance performance. Conducting polymers (CPs) are among the most potential pseudocapacitor materials for the foundation of flexible supercapacitors, motivating the existing energy storage devices toward the future advanced flexible electronic applications due to their high redox active‐specific capacitance and inherent elastic polymeric nature. This review focuses on different types of CPs‐based supercapacitor, the relevant fabrication methods and designing concepts. It describes recent developments and remaining challenges in this field, and its impact on the future direction of flexible supercapacitor materials and relevant device fabrications.
The conducting polymer‐based redox materials are bringing a revolution in the flexible pseudo‐capacitor applications. The future of the CPs‐based flexible energy storage devices hold even greater promise for a novel low cost, light‐weight and highly flexible devices.
The production of renewable solar fuel through CO2 photoreduction, namely artificial photosynthesis, has gained tremendous attention in recent times due to the limited availability of fossil-fuel ...resources and global climate change caused by rising anthropogenic CO2 in the atmosphere. In this study, graphene oxide (GO) decorated with copper nanoparticles (Cu-NPs), hereafter referred to as Cu/GO, has been used to enhance photocatalytic CO2 reduction under visible-light. A rapid one-pot microwave process was used to prepare the Cu/GO hybrids with various Cu contents. The attributes of metallic copper nanoparticles (∼4–5 nm in size) in the GO hybrid are shown to significantly enhance the photocatalytic activity of GO, primarily through the suppression of electron–hole pair recombination, further reduction of GO’s bandgap, and modification of its work function. X-ray photoemission spectroscopy studies indicate a charge transfer from GO to Cu. A strong interaction is observed between the metal content of the Cu/GO hybrids and the rates of formation and selectivity of the products. A factor of greater than 60 times enhancement in CO2 to fuel catalytic efficiency has been demonstrated using Cu/GO-2 (10 wt % Cu) compared with that using pristine GO.
Paper-based biosensors are considered simple and cost-efficient sensing platforms for analytical tests and diagnostics. Here, a paper-based electrochemical biosensor was developed for the rapid and ...sensitive detection of microRNAs (miRNA-155 and miRNA-21) related to early diagnosis of lung cancer. Hydrophobic barriers to creating electrode areas were manufactured by wax printing, whereas a three-electrode system was fabricated by a simple stencil approach. A carbon-based working electrode was modified using either reduced graphene oxide or molybdenum disulfide nanosheets modified with gold nanoparticle (AuNPs/RGO, AuNPs/MoS2) hybrid structures. The resulting paper-based biosensors offered sensitive detection of miRNA-155 and miRNA-21 by differential pulse voltammetry (DPV) in only 5.0 µL sample. The duration in our assay from the point of electrode modification to the final detection of miRNA was completed within only 35 min. The detection limits for miRNA-21 and miRNA-155 were found to be 12.0 and 25.7 nM for AuNPs/RGO and 51.6 and 59.6 nM for AuNPs/MoS2 sensors in the case of perfectly matched probe-target hybrids. These biosensors were found to be selective enough to distinguish the target miRNA in the presence of single-base mismatch miRNA or noncomplementary miRNA sequences.
In this study, we have successfully demonstrated that a GaN nanowire (GaNNW) based extended-gate field-effect-transistor (EGFET) biosensor is capable of specific DNA sequence identification under ...label-free in situ conditions. Our approach shows excellent integration of the wide bandgap semiconducting nature of GaN, surface-sensitivity of the NW-structure, and high transducing performance of the EGFET-design. The simple sensor-architecture, by direct assembly of as-synthesized GaNNWs with a commercial FET device, can achieve an ultrahigh detection limit below attomolar level concentrations: about 3 orders of magnitude higher in resolution than that of other FET-based DNA-sensors. Comparative in situ studies on mismatches (“hotspot” mutations related to human p53 tumor-suppressor gene) and complementary targets reveal excellent selectivity and specificity of the sensor, even in the presence of noncomplementary DNA strands, suggesting the potential pragmatic application in complex clinical samples. In comparison with GaN thin film, NW-based EGFET exhibits excellent performance with about 2 orders higher sensitivity, over a wide detection range, 10−19−10−6 M, reaching about a 6-orders lower detection limit. Investigations illustrate the unique and distinguished feature of nanomaterials. Detailed studies indicate a positive effect of energy band alignment at the biomaterials−semiconductor hybrid interface influencing the effective capacitance and carrier-mobility of the system.
Business Model Innovation in Practice Euchner, Jim; Ganguly, Abhijit
Research technology management,
11/1/2014, 20141101, Letnik:
57, Številka:
6
Journal Article
Recenzirano
Business model innovation is often the key to capturing value from innovation within corporations. Developing and implementing new business models in practice, however, is difficult and fraught with ...risk. This paper discusses a systematic approach to developing new business models and identifies concrete steps to reduce the risks associated with them. It draws on literature on elements of the process as well as experience developing and implementing new business models at Goodyear.
Conducting Business Experiments Ganguly, Abhijit; Euchner, Jim
Research technology management,
20/3/4/, Letnik:
61, Številka:
2
Journal Article
Recenzirano
Breakthrough innovation inside established companies-innovation that creates new revenue streams-often requires business model innovation in addition to innovation in product or offering. ...Unfortunately, new business models are rife with uncertainty. They may require new channels or new partnerships, appeal to new customer sets, rely on different revenue models, or require unfamiliar technologies. The risk associated with creating new business models is a major reason high-potential new businesses are not launched inside established companies. Well-designed business experiments are a valuable tool for reducing that risk. Although business experiments are not new, much of the literature concerning such experiments focuses on software and Internet businesses, where experiments are easier to conduct, and on startup companies rather than large corporations. This paper addresses the conduct of experiments in companies that produce physical goods and addresses the issues associated with conducting experiments within an established company. It describes methods used to design experiments, to focus them on critical issues, and to manage them in a corporate context.
Breakthrough innovation inside established companies--innovation that creates new revenue streams--often requires business model innovation in addition to innovation in product or offering. ...Unfortunately, new business models are rife with uncertainty. They may require new channels or new partnerships, appeal to new customer sets, rely on different revenue modeis, or require unfamiliar technologies. The risk associated with creating new business models is a major reason high-potential new businesses are not launched inside established companies. Well-designed business experiments are a valuable tool for reducing that risk. Although business experiments are not new, much of the literature concerning such experiments focuses on software and Internet businesses, where experiments are easier to conduct, and on startup companies rather than large corporations. This paper addresses the conduct of experiments in companies that produce physical goods and addresses the issues associated with conducting experiments within an established company. It describes methods used to design experiments, to focus them on critical issues, and to manage them in a corporate context.
This review will give a brief introduction to the growth and characterization methods of both binary and ternary compounds, in particular those exhibiting one-dimensionality, of the family to orient ...the readers about the material system to be discussed. A section will deal with the size and shape selection in group III nitride nanomaterials with a stress on intriguing morphologies such as nanowires, nanotips, and nanobelts. Complex structures, such as hierarchical and core-shell structures, will be introduced. Optical, electrical, and mechanical property, such as hardness, will be discussed in a greater detail, distinguishing the bulk from the nano wherever possible. Available models of electrical conduction and photoconduction in nanomaterials and their dependence on the actual size of the objects will be presented and compared. Optical properties of ensemble and single nanostructures, wherever possible, will be addressed in detail. The section on application will focus mainly on the sensor applications, including chemical sensors, gas sensors, and biosensors, with a thrust on DNA sensing. Because popular applications such as light-emitting diodes (LEDs) and field effect transistors (FETs) have already been reviewed extensively, only major contributions to this field-for example, nano-LEDs-will be discussed. Some recent advances in the group III-nitride materials family will be presented that will indicate future directions of research in this area.
PDF
