Acenes have long been the subject of intense study because of the unique electronic properties associated with their π-bond topology. Recent reports of impressive semiconductor properties of larger ...homologues have reinvigorated research in this field, leading to new methods for their synthesis, functionalization, and purification, as well as for fabricating organic electronic components. Studies performed on high-purity acene single crystals revealed their intrinsic electronic properties and provide useful benchmarks for thin film device research. New approaches to add functionality were developed to improve the processability of these materials in solution. These new functionalization strategies have recently allowed the synthesis of acenes larger than pentacene, which have hitherto been largely unavailable and poorly studied, as well as investigation of their associated structure/property relationships.
Lost at Sea: Where Is All the Plastic? Thompson, Richard C.; Olsen, Ylva; Mitchell, Richard P. ...
Science (American Association for the Advancement of Science),
05/2004, Letnik:
304, Številka:
5672
Journal Article
Recenzirano
Thompson et al seek to establish that microscopic plastic fragments and fibers are also widespread in the oceans and have accumulated in the pelagic zone and sedimentary habitats. To quantify the ...abundance of microplastics, they collected sediment from beaches and from estuarine and subtidal sediments around Plymouth, UK. To assess the extent of contamination, a further 17 beaches were examined, and similar fibers were found, demonstrating that microscopic plastics are common in sedimentary forms. Their findings demonstrate that the broad spatial extent and accumulation of this type of contamination. Given the rapid increase in plastic production, the longevity of plastic, and the disposable nature of plastic items, the contamination is likely to increase, aside from the potential for plastics to adsorb, release, and transport chemicals. However, it remains to be shown whether toxic substances can pass from plastics to the food chain.
The importance and performance of organic electronic devices have increased significantly over the last 20 years. This review highlights the functionalization of linearly fused aromatic systems ...specifically for their application in electronic devices, particularly crystal structure/device property relationships in linearly fused acenes and heteroacenes.
In the field of polymer bulk-heterojunction organic photovoltaics, fullerenes and fullerene derivatives clearly play the dominant role as acceptor materials. Recently, a number of research efforts ...have focused on the development of new small-molecule acceptors for this device configuration. Although few materials prepared to-date have demonstrated power conversion efficiencies close to those achieved with fullerenes, numerous design rules and some interesting new materials classes have been explored. This short review will highlight the progress toward higher efficiency in nonfullerene small-molecule acceptors for organic solar cells.
Although promising, the use of organic semiconductors has not yet revolutionized consumer electronics. Synthesis of high-performance materials, enhanced control of morphology and smart exploitation ...of unique photophysical phenomena are the way forward to overcome the technological hurdles of this field.
Organic semiconductors have been the subject of intensive academic and commercial interest over the past two decades, and successful commercial devices incorporating them are slowly beginning to ...enter the market. Much of the focus has been on the development of hole transporting, or p‐type, semiconductors that have seen a dramatic rise in performance over the last decade. Much less attention has been devoted to electron transporting, or so called n‐type, materials, and in this paper we focus upon recent developments in several classes of n‐type materials and the design guidelines used to develop them.
Recent progress in the development of n‐type organic semiconductors for a range of applications, including field‐effect transistors and solar cells is reviewed. We focus on the design guidelines used to develop n‐type materials by examining several illustrative materials classes including fullerenes, rylenes, acenes, and siloles.
Organic semiconductors might enable new applications in low-cost, light-weight, flexible electronics. To build a solid foundation for these technologies, more fundamental studies of ...electro-mechanical properties of various types of organic semiconductors are necessary. Here we perform basic studies of charge transport in highly crystalline solution-processed organic semiconductors as a function of applied mechanical strain. As a test bed, we use small molecules crystallized on thin plastic sheets, resulting in high-performance flexible field-effect transistors. These devices can be bent multiple times without degradation to a radius as small as ~200 μm, demonstrating that crystalline solution-processed organic semiconductors are intrinsically highly flexible. This study of electro-mechanical properties suggests that solution-processable organic semiconductors are suitable for applications in flexible electronics, provided that integration with other important technological advances, such as device scalability and low-voltage operation, is achieved in the future.
A combination of surface energy‐guided blade coating and inkjet printing is used to fabricate an all‐printed high performance, high yield, and low variability organic thin film transistor (OTFT) ...array on a plastic substrate. Functional inks and printing processes were optimized to yield self‐assembled homogenous thin films in every layer of the OTFT stack. Specifically, we investigated the effect of capillary number, semiconductor ink composition (small molecule‐polymer ratio), and additive high boiling point solvent concentrations on film fidelity, pattern design, device performance and yields.
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