Improvement of the physical properties of ZnO/CdTe core-shell nanowire arrays by CdCl2 heat treatment for solar cells

Abstract CdTe is an important compound semiconductor for solar cells, and its use in nanowire-based heterostructures may become a critical requirement, owing to the potential scarcity of tellurium. The effects of the CdCl2 heat treatment are investigated on the physical properties of vertically aligned ZnO/CdTe core-shell nanowire arrays grown by combining chemical bath deposition with close space sublimation. It is found that recrystallization phenomena are induced by the CdCl2 heat treatment in the CdTe shell composed of nanograins: its crystallinity is improved while grain growth and texture randomization occur. The presence of a tellurium crystalline phase that may decorate grain boundaries is also revealed. The CdCl2 heat treatment further favors the chlorine doping of the CdTe shell with the formation of chlorine A-centers and can result in the passivation of grain boundaries. The absorption properties of ZnO/CdTe core-shell nanowire arrays are highly efficient, and more than 80% of the incident light can be absorbed in the spectral range of the solar irradiance. The resulting photovoltaic properties of solar cells made from ZnO/CdTe core-shell nanowire arrays covered with CuSCN/Au back-side contact are also improved after the CdCl2 heat treatment. However, recombination and trap phenomena are expected to operate, and the collection of the holes that are mainly photo-generated in the CdTe shell from the CuSCN/Au back-side contact is presumably identified as the main critical point in these solar cells.This work has been supported by the Nanosciences Foundation of Grenoble through the project II-VI Photovoltaic and by Grenoble INP with a Bonus Qualité Recherche grant through the project CELESTE. This work has also been partially supported by the Spanish Ministry under contract MAT2010-16116.Peer Reviewe

Light trapping and physical properties of ZnO / CdTe core shell nanowire arrays for solar cells

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Optical absorption and physical properties of ZnO/CdTe core shell nanowire arrays for solar cells

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Giving a voice to patients at high risk of dying in the intensive care unit: a multiple source approach

Purpose Data are scarce regarding the experience of critically ill patients at high risk of death. Identifying their concerns could allow clinicians to better meet their needs and align their end-of-life trajectory with their preferences and values. We aimed to identify concerns expressed by conscious patients at high risk of dying in the intensive care unit (ICU). Methods Multiple source multicentre study. Concerns expressed by patients were collected from five different sources (literature review, panel of 50 ICU experts, prospective study in 11 ICUs, in-depth interviews with 17 families and 15 patients). All qualitative data collected were analyzed using thematic content analysis. Results The five sources produced 1307 concerns that were divided into 7 domains and 41 sub-domains. After removing redundant items and duplicates, and combining and reformulating similar items, 28 concerns were extracted from the analysis of the data. To increase accuracy, they were merged and consolidated, and resulted in a final list of 15 concerns pertaining to seven domains: concerns about loved-ones; symptom management and care (including team competence, goals of care discussions); spiritual, religious, and existential preoccupations (including regrets, meaning, hope and trust); being oneself (including fear of isolation and of being a burden, absence of hope, and personhood); the need for comforting experiences and pleasure; dying and death (covering emotional and practical concerns); and after death preoccupations. Conclusion This list of 15 concerns may prove valuable for clinicians as a tool for improving communication and support to better meet the needs of patients at high risk of dying

Altered bioavailability of epoxyeicosatrienoic acids is associated with conduit artery endothelial dysfunction in type 2 diabetic patients

International audienceBackground: This pathophysiological study addressed the hypothesis that soluble epoxide hydrolase (sEH), which metabolizes the vasodilator and anti-inflammatory epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids (DHETs), contributes to conduit artery endothelial dysfunction in type 2 diabetes. Methods and results: Radial artery endothelium-dependent flow-mediated dilatation in response to hand skin heating was reduced in essential hypertensive patients (n = 9) and type 2 diabetic subjects with (n = 19) or without hypertension (n = 10) compared to healthy subjects (n = 36), taking into consideration cardiovascular risk factors, flow stimulus and endothelium-independent dilatation to glyceryl trinitrate. Diabetic patients but not non-diabetic hyper-tensive subjects displayed elevated whole blood reactive oxygen species levels and loss of NO release during heating, assessed by measuring local plasma nitrite variation. Moreover, plasma levels of EET regioisomers increased during heating in healthy subjects, did not change in hypertensive patients and decreased in diabetic patients. Correlation analysis showed in the overall population that the less NO and EETs bioavailability increases during heating, the more flow-mediated dilatation is reduced. The expression and activity of sEH, measured in isolated peripheral blood mono-nuclear cells, was elevated in diabetic but not hypertensive patients, leading to increased EETs conversion to DHETs. Finally, hyperglycemic and hyperinsulinemic euglycemic clamps induced a decrease in flow-mediated dilatation in healthy subjects and this was associated with an altered EETs release during heating. Conclusions: These results demonstrate that an increased EETs degradation by sEH and altered NO bioavailability are associated with conduit artery endothelial dysfunction in type 2 diabetic patients independently from their hyperten-sive status. The hyperinsulinemic and hyperglycemic state in these patients may contribute to these alterations

CRISPR/Cas9-mediated inactivation of the phosphatase activity of soluble epoxide hydrolase prevents obesity and cardiac ischemic injury

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CRISPR/Cas9-mediated inactivation of the phosphatase activity of soluble epoxide hydrolase prevents obesity and cardiac ischemic injury

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CRISPR/Cas9-mediated inactivation of the phosphatase activity of soluble epoxide hydrolase prevents obesity and cardiac ischemic injury

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