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•We study variation in mobility measurements on organic films.•Values extracted by different scientists typically vary by about a factor of 3.•We propose a protocol that drastically ...reduces this variation.•Control of film thickness and electrode quality are also important factors.
Charge carrier mobility is a figure of merit commonly used to rate organic semiconducting materials for their suitability in applications such as solid-state lighting or photovoltaics. Although large variations are found in published mobility values on identical materials, there is little open discussion in the literature of the reproducibility of these results. We address this with an interlaboratory study of mobility measurements performed on a set of organic semiconductors using the space-charge limited current method. We found mobility measured on nominally identical devices could vary by more than one order of magnitude, with the largest sources of variation being poor electrodes and film thickness variation. Moreover, we found that mobility values extracted from identical data by different scientists would typically vary by a factor of 3. We propose a protocol for analysis and reporting that was found to reduce this analysis variation to as little as 20%. We also present general guidelines for improving the reproducibility of benchmark mobility measurements.
Halide double perovskites have recently bloomed as the green candidates for optoelectronic applications, such as X‐ray detection. Despite great efforts, the exploration of promising organic–inorganic ...hybrid double perovskites toward X‐ray detection remains unsuccessful. Now, single crystals of the lead‐free hybrid double perovskite, (BA)2CsAgBiBr7 (BA+ is n‐butylammonium), featuring the unique 2D multilayered quantum‐confined motif, enable quite large μτ (mobility‐lifetime) product up to 1.21×10−3 cm2 V−1. This figure‐of‐merit realized in 2D hybrid double perovskites is unprecedented and comparable with that of CH3NH3PbI3 wafers. (BA)2CsAgBiBr7 crystals also exhibit other intriguing attributes for X‐ray detection, including high bulk resistivity, low density of defects and traps, and large X‐ray attenuation coefficient. Consequently, a vertical‐structure crystal device under X‐ray source yields a superior sensitivity of 4.2 μC Gyair−1 cm−2.
Finding X‐rays: Single crystals of a lead‐free hybrid double perovskite, (BA)2CsAgBiBr7 (BA+: n‐Butylammonium), adopting a unique 2D multilayered quantum‐confined motif, can serve as a potential X‐ray detecting material. This promise stems from the large μτ product of 1.21×10−3 cm2 V−1, high bulk resistivity, low trap density, and efficient X‐ray attenuation.
Proteomic measurements with greater throughput, sensitivity, and structural information are essential for improving both in‐depth characterization of complex mixtures and targeted studies. While LC ...separation coupled with MS (LC–MS) measurements have provided information on thousands of proteins in different sample types, the introduction of a separation stage that provides further component resolution and rapid structural information has many benefits in proteomic analyses. Technical advances in ion transmission and data acquisition have made ion mobility separations an opportune technology to be easily and effectively incorporated into LC–MS proteomic measurements for enhancing their information content. Herein, we report on applications illustrating increased sensitivity, throughput, and structural information by utilizing IMS–MS and LC–IMS–MS measurements for both bottom‐up and top‐down proteomics measurements.
•GC–IMS applied to food flavor analysis has rapidly developed in the past few years.•It is used for classification, adulteration studies, spoilage, off-flavor detection, etc.•GC–IMS is fast, ...convenient and precise with great future potential.
Rapid, nondestructive, high-throughput testing and screening of volatile ingredients plays an important role in food flavor analysis. Gas chromatography–ion mobility spectrometry (GC–IMS) is a powerful technique for the separation and sensitive detection of volatile organic compounds. It has a fast response, high sensitivity, easy operation, and low cost. In this article, a brief introduction to the working principle of GC–IMS is presented. A summary of recent studies of different food flavor analysis applications is also provided, including food classification and adulteration, the evaluation of food freshness and spoilage, off-flavor detection, monitoring the processing of food products, and evaluation of aroma changes during food storage. Finally, future directions of GC–IMS are proposed.
We explore the relationship between university graduates' early career decisions and their interregional mobility. We focus on graduates' immediate entry into the labour market, analysing the ...antecedents and relations of their career decisions (self-employment versus salaried job) and mobility choices (staying in their university region or moving). We use a longitudinal dataset of 3436 students from 62 Italian universities who were surveyed at graduation and one year later. We find that self-employment most likely occurs among those who study and stay in their home region, as well as those who study in a different region and return to their home one. Conversely, salaried positions are more appealing to those who, after graduation, move to a region other than their home one. Individual characteristics explain the decision to enter self-employment or accept a salaried job. In contrast, the decision to move or stay is mainly affected by contextual factors.
Lead halide perovskite semiconductors are in general known to have an inherently high X-ray absorption cross-section and a significantly higher carrier mobility than any other low-temperature ...solution-processed semiconductor. So far, the processing of several-hundred-micrometres-thick high-quality crystalline perovskite films over a large area has been unresolved for efficient X-ray detection. In this Article, we present a mechanical sintering process to fabricate polycrystalline methyl ammonium lead triiodide perovskite (MAPbI3 ) wafers with millimetre thickness and well-defined crystallinity. Benchmarking of the MAPbI3 wafers against state-of-the-art CdTe detectors reveals competitive conversion efficiencies of 2,527 µC Gyair -1 cm-2 under 70 kVp X-ray exposure. The high ambipolar mobility-lifetime product of 2 × 10-4 cm2 V-1 is suggested to be responsible for this exceptionally high sensitivity. Our findings inform a new generation of highly efficient and low-cost X-ray detectors based on perovskite wafers.
This paper serves as an update to the previous RESNA Position on the Application of Power Wheelchairs for Pediatric Users with more current and additional scientific literature. This document ...contains typical clinical applications and best evidence from the literature supporting the application of power mobility (PM) for young children and to assist practitioners in decision-making and justification. It is RESNA' s position that age, limited vision or cognition, behavioral issues, and the ability to walk or propel a manual wheelchair short distances should not, in and of themselves, be used as discriminatory factors against providing PM for children. RESNA recommends early utilization of PM for children with mobility limitations as medically necessary, to promote integration and psycho-social development, reduce passive dependency, and to enhance participation, function, and independence.
•Despite increased attention for MaaS, well-designed pilot studies are rare.•Results from an exploratory MaaS pilot study (100 participants) are presented.•Findings suggest MaaS mainly complements ...car possession and car use.•Interrelation between MaaS and private car is bound to be complex.
Mobility-as-a-Service (MaaS) has received widespread attention over the past couple of years amongst scholars, businesses, policymakers and mainstream media. Most coverage is oriented towards its possible gains for traveling individuals and the travel industry, while still lacking conceptual clarity and sufficient detail about its potential acceptance by the general public. This leads to varying perspectives on what MaaS precisely is and will be in the near future. In this study, we reflect upon the relationship between MaaS use and private car ownership, based on insights gained from a MaaS pilot study organized mid-2017 in Ghent (Belgium). This exploratory pilot study targeted 100 car-owning participants (i.e., Ghent University employees) and explored how these motivated people can replace or significantly reduce car use in return for a monthly mobility budget which they could spend on MaaS services. The study reveals that most respondents were apt to explore MaaS services (especially public transport and car sharing services), but a clear reduction of private car use remained difficult in a real-life setting. Despite being highly motivated to reduce car use and being given incentives, participants faced considerable difficulties in bypassing their personal car, especially for (non-repetitive) leisure trips. By drawing parallels with a similar debate in the transport literature from a couple of decades ago, we suggest that MaaS should be regarded as a complement – rather than a substitution – of private car use in the near future. The relationship between MaaS use and car ownership might in reality be more complex than generally acknowledged. In addressing these parallels, the paper opens up new critical questions for MaaS research in the future.
Over the past three decades, significant research efforts have focused on improving the charge carrier mobility of organic thin‐film transistors (OTFTs). In recent years, a commonly observed ...nonlinearity in OTFT current–voltage characteristics, known as the “kink” or “double slope,” has led to widespread mobility overestimations, contaminating the relevant literature. Here, published data from the past 30 years is reviewed to uncover the extent of the field‐effect mobility hype and identify the progress that has actually been achieved in the field of OTFTs. Present carrier‐mobility‐related challenges are identified, finding that reliable hole and electron mobility values of 20 and 10 cm2 V−1 s−1, respectively, have yet to be achieved. Based on the analysis, the literature is then reviewed to summarize the concepts behind the success of high‐performance p‐type polymers, along with the latest understanding of the design criteria that will enable further mobility enhancement in n‐type polymers and small molecules, and the reasons why high carrier mobility values have been consistently produced from small molecule/polymer blend semiconductors. Overall, this review brings together important information that aids reliable OTFT data analysis, while providing guidelines for the development of next‐generation organic semiconductors.
Overestimated carrier mobility values reported in recent years for organic thin‐film transistors (OTFTs) have contaminated the literature. 30 years of OTFT carrier mobility data is examined in an effort to identify actual progress achieved, and summarize the key design strategies behind high carrier mobility values for both p‐ and n‐type organic semiconductors.
Dislocation glide is a general deformation mode, governing the strength of metals. Via discrete dislocation dynamics and molecular dynamics simulations, we investigate the strain rate and dislocation ...density dependence of the strength of bulk copper and aluminum single crystals. An analytical relationship between material strength, dislocation density, strain rate and dislocation mobility is proposed, which agrees well with current simulations and published experiments. Results show that material strength displays a decreasing regime (strain rate hardening) and then increasing regime (classical forest hardening) as the dislocation density increases. Accordingly, the strength displays universally, as the strain rate increases, a strain rate-independent regime followed by a strain rate hardening regime. All results are captured by a single scaling function, which relates the scaled strength to a coupling parameter between dislocation density and strain rate. Such coupling parameter also controls the localization of plasticity, fluctuations of dislocation flow and distribution of dislocation velocity.
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