On the unipolarity of charge transport in methanofullerene diodes

Fullerenes are electron transporting organic semiconductors with a wide range of applications. In particular, methanofullereneshave been the preferred choice for solution-processed solar cells and photodiodes. The wide applicability of fullerenes as both ‘ntype’transport materials and electron acceptors is clear. However, what is still a matter of debate is whether the fullerenes can alsosupport efficient transport of holes, particularly in diode geometries. In this letter, we utilize a number of recently developedexperimental methods for selective electron and hole mobility measurements. We show for the two most widely used solutionprocessable fullerenes, PC70- and-PC60BM, that whilst both exhibit electron mobilities as high as 10−3 cm2/Vs, their hole mobilities

Ambipolar Deep-Subthreshold Printed-Carbon-Nanotube Transistors for Ultralow-Voltage and Ultralow-Power Electronics.

The development of ultralow-power and easy-to-fabricate electronics with potential for large-scale circuit integration (i.e., complementary or complementary-like) is an outstanding challenge for emerging off-the-grid applications, e.g., remote sensing, "place-and-forget", and the Internet of Things. Herein we address this challenge through the development of ambipolar transistors relying on solution-processed polymer-sorted semiconducting carbon nanotube networks (sc-SWCNTNs) operating in the deep-subthreshold regime. Application of self-assembled monolayers at the active channel interface enables the fine-tuning of sc-SWCNTN transistors toward well-balanced ambipolar deep-subthreshold characteristics. The significance of these features is assessed by exploring the applicability of such transistors to complementary-like integrated circuits, with respect to which the impact of the subthreshold slope and flatband voltage on voltage and power requirements is studied experimentally and theoretically. As demonstrated with inverter and NAND gates, the ambipolar deep-subthreshold sc-SWCNTN approach enables digital circuits with complementary-like operation and characteristics including wide noise margins and ultralow operational voltages (≤0.5 V), while exhibiting record-low power consumption (≤1 pW/μm). Among thin-film transistor technologies with minimal material complexity, our approach achieves the lowest energy and power dissipation figures reported to date, which are compatible with and highly attractive for emerging off-the-grid applications

Performance and energy-efficient implementation of a smart city application on FPGAs

The continuous growth of modern cities and the request for better quality of life, coupled with the increased availability of computing resources, lead to an increased attention to smart city services. Smart cities promise to deliver a better life to their inhabitants while simultaneously reducing resource requirements and pollution. They are thus perceived as a key enabler to sustainable growth. Out of many other issues, one of the major concerns for most cities in the world is traffic, which leads to a huge waste of time and energy, and to increased pollution. To optimize traffic in cities, one of the first steps is to get accurate information in real time about the traffic flows in the city. This can be achieved through the application of automated video analytics to the video streams provided by a set of cameras distributed throughout the city. Image sequence processing can be performed both peripherally and centrally. In this paper, we argue that, since centralized processing has several advantages in terms of availability, maintainability and cost, it is a very promising strategy to enable effective traffic management even in large cities. However, the computational costs are enormous, and thus require an energy-efficient High-Performance Computing approach. Field Programmable Gate Arrays (FPGAs) provide comparable computational resources to CPUs and GPUs, yet require much lower amounts of energy per operation (around 6$$\times$$ and 10$$\times$$ for the application considered in this case study). They are thus preferred resources to reduce both energy supply and cooling costs in the huge datacenters that will be needed by Smart Cities. In this paper, we describe efficient implementations of high-performance algorithms that can process traffic camera image sequences to provide traffic flow information in real-time at a low energy and power cost

Forward Value Creation and Digital Government: Solving the Cost-Benefit Paradox?

While adoption of new technologies and supply of online services are in focus of measuring uptake of online services in maturity models, measurement of direct and indirect outcome and value creation for the internal and external end-users are only marginal addressed. Based on three vignettes from Norway, this paper argues that the importance of cost overrun is overestimated in the short run, while long-term benefits, as well as indirect benefits, are underestimated in public sector it-projects. We present a set of propositions for future government digitalization projects, bringing attention to the involvement of internal and external users, and bringing focus to balancing short term and long term direct and indirect costs

External User Inclusion in Public e-Service Development : Exploring the Current Practice in Sweden

For the last decade e-government research has underlined the importance of an external user perspective in public e-service development and there have been numerous attempts to provide guidance and directions for government agencies in this matter. Individual research studies show little progress in this matter, but a more generalisable picture of the current state of external user inclusion is missing. The aim of this paper is to provide a better and more generalisable understanding of Swedish government agencies’ current practice of external user inclusion in public e-service development. In order to do so, we have interviewed Swedish government agencies regarding their perceptions on external user inclusion. Our findings show mixed results regarding attitudes towards and current practice of external user inclusion. It is clear that organisational size and previous experience of public e-service development matter. At the same time challenges such as a general lack of resurces and a lack of time are seen as general barriers, regardless of agency level and size