68 research outputs found
Physical routes for the synthesis of kesterite
This paper provides an overview of the physical vapor technologies used to synthesize Cu2ZnSn(S,Se)4
thin films as absorber layers for photovoltaic applications. Through the years, CZT(S,Se) thin films
have been fabricated using sequential stacking or co-sputtering of precursors as well as using
sequential or co-evaporation of elemental sources, leading to high-efficient solar cells. In addition,
pulsed laser deposition of composite targets and monograin growth by the molten salt method were
developed as alternative methods for kesterite layers deposition. This review presents the growing
increase of the kesterite-based solar cell efficiencies achieved over the recent years. A historical
description of the main issues limiting this efficiency and of the experimental pathways designed to
prevent or limit these issues is provided and discussed as well. Afinal section is dedicated to the
description of promising process steps aiming at further improvements of solar cell efficiency, such as
alkali doping and bandgap grading1. R Caballero and M León acknowledge financial support via the Spanish Ministry of Science, Innovation and Universities project (WINCOST, ENE2016-80788-C5-2-R) and thank H2020 EU Programme under the project INFINITE-CELL (H2020-MSCA-RISE-2017-777968).
2. S Canulescu and J Schou acknowledge the support from Innovation Fund Denmark.
3. D-H Kim acknowledges financial support via the DGIST R&D Program of the Ministry of Science and ICT, KOREA (18-BD-05).
4.C. Malerba acknowledges the support from the Italian Ministry of Economic development in the framework of the Operating Agreement with ENEA for the Research on the Electric System.
5.A Redinger acknowledges financial support via the FNR Attract program, Project : SUNSPOT, Nr.11244141.
6. E Saucedo thanks H2020 EU Programme under the projects STARCELL (H2020-NMBP-03-2016-720907) and INFINITE-CELL (H2020-MSCA-RISE-2017-777968), the Spanish Ministry of Science, Innovation and Universities for the IGNITE project (ENE2017-87671-C3-1-R), and the European Regional Development Funds (ERDF, FEDER Programa Competitivitat de Catalunya 2007–2013). IREC belong to
the SEMS (Solar Energy Materials and Systems) Consolidated Research Group of the ‘Generalitat de Catalunya’ (Ref. 2017 SGR 862).
7. Taltech acknowledges financial support via the Estonian Ministry of Education and Research funding project IUT19-28 and the European Union Regional Development Fund, Project TK141.
8. B Vermang has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme (Grant Agreement No 715027
Emerging nanomagnetism in 4d transition metal nanowires
Monatomic nanowires of the nonmagnetic transition metals Ru, Rh, and Pd have
been studied theoretically, using first-principles computational techniques, in
order to investigate the possible onset of magnetism in these nanosystems. Our
fully relativistic spin-polarized all-electron density functional calculations
reveal the onset of Hund's rule magnetism in nanowires of all three metals,
with mean-field moments of 1.1, 0.3, and 0.7 bohr magnetons, respectively, at
the equilibrium bond length. An analysis of the band structures indicates that
the nanocontact superparamagnetic state suggested by our calculations should
affect the ballistic conductance between tips made of Ru, Rh or Pd, leading to
possible temperature and magnetic field dependent conductance.Comment: 5 figures, 17 pages New content with respect to old arxiv versio
Π-Π interactions stabilize PeptoMicelle-based formulations of Pretomanid derivatives leading to promising therapy against tuberculosis in zebrafish and mouse models
Tuberculosis is the deadliest bacterial disease globally, threatening the lives of millions every year. New antibiotic therapies that can shorten the duration of treatment, improve cure rates, and impede the development of drug resistance are desperately needed. Here, we used polymeric micelles to encapsulate four second-generation derivatives of the antitubercular drug pretomanid that had previously displayed much better in vivo activity against Mycobacterium tuberculosis than pretomanid itself. Because these compounds were relatively hydrophobic and had limited bioavailability, we expected that their micellar formulations would overcome these limitations, reduce toxicities, and improve therapeutic outcomes. The polymeric micelles were based on polypept(o)ides (PeptoMicelles) and were stabilized in their hydrophobic core by π-π interactions, allowing the efficient encapsulation of aromatic pretomanid derivatives. The stability of these π-π-stabilized PeptoMicelles was demonstrated in water, blood plasma, and lung surfactant by fluorescence cross-correlation spectroscopy and was further supported by prolonged circulation times of several days in the vasculature of zebrafish larvae. The most efficacious PeptoMicelle formulation tested in the zebrafish larvae infection model almost completely eradicated the bacteria at non-toxic doses. This lead formulation was further assessed against Mycobacterium tuberculosis in the susceptible C3HeB/FeJ mouse model, which develops human-like necrotic granulomas. Following intravenous administration, the drug-loaded PeptoMicelles significantly reduced bacterial burden and inflammatory responses in the lungs and spleens of infected mice.Drug Delivery Technolog
Secondary crystalline phases identification in Cu2ZnSnSe4 thin films: contributions from Raman scattering and photoluminescence
In this work, we present the Raman peak
positions of the quaternary pure selenide compound
Cu2ZnSnSe4 (CZTSe) and related secondary phases that
were grown and studied under the same conditions. A vast
discussion about the position of the X-ray diffraction
(XRD) reflections of these compounds is presented. It is
known that by using XRD only, CZTSe can be identified
but nothing can be said about the presence of some secondary
phases. Thin films of CZTSe, Cu2SnSe3, ZnSe,
SnSe, SnSe2, MoSe2 and a-Se were grown, which allowed
their investigation by Raman spectroscopy (RS). Here we
present all the Raman spectra of these phases and discuss
the similarities with the spectra of CZTSe. The effective
analysis depth for the common back-scattering geometry
commonly used in RS measurements, as well as the laser penetration depth for photoluminescence (PL) were estimated
for different wavelength values. The observed
asymmetric PL band on a CZTSe film is compatible with
the presence of CZTSe single-phase and is discussed in the
scope of the fluctuating potentials’ model. The estimated
bandgap energy is close to the values obtained from
absorption measurements. In general, the phase identification
of CZTSe benefits from the contributions of RS and
PL along with the XRD discussion.info:eu-repo/semantics/publishedVersio
First-principles calculation of positron lifetimes and affinities in perfect and imperfect transition-metal carbides and nitrides
Enhanced Electrical Conductivity of Silver Nanoparticles for High Frequency Electronic Applications
Neuronal apoptosis by HIV-1 Vpr: contribution of proinflammatory molecular networks from infected target cells
Background: Human immunodeficiency virus type 1 (HIV-1) induces neuronal dysfunction through host cellular factors and viral proteins including viral protein R (Vpr) released from infected macrophages/microglia. Vpr is important for infection of terminally differentiated cells such as macrophages. The objective of this study was to assess the effect of Vpr in the context of infectious virus particles on neuronal death through proinflammatory cytokines released from macrophages.Methods: Monocyte-derived macrophages (MDM) were infected with either HIV-1 wild type (HIV-1wt), Vpr deleted mutant (HIV-1{increment}Vpr) or mock. Cell lysates and culture supernatants from MDMs were analyzed for the expression and release of proinflammatory cytokines by quantitative reverse transcription-PCR and enzyme-linked immunosorbent assay respectively. Mitogen-activated protein kinases (MAPK) were analyzed in activated MDMs by western blots. Further, the effect of Vpr on neuronal apoptosis was examined using primary neurons exposed to culture supernatants from HIV-1wt, HIV-1{increment}Vpr or mock-infected MDMs by Annexin-V staining, MTT and Caspase - Glo® 3/7 assays. The role of interleukin (IL)-1β, IL-8 and tumor necrosis factor (TNF)-α on neuronal apoptosis was also evaluated in the presence or absence of neutralizing antibodies against these cytokines.Results: HIV-1{increment}Vpr-infected MDMs exhibited reduced infection over time and specifically a significant downregulation of IL-1β, IL-8 and TNF-α at the transcriptional and/or protein levels compared to HIV-1wt-infected cultures. This downregulation was due to impaired activation of p38 and stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK) in HIV-1{increment}Vpr-infected MDMs. The association of SAPK/JNK and p38 to IL-1β and IL-8 production was confirmed by blocking MAPKs that prevented the elevation of IL-1β and IL-8 in HIV-1wt more than in HIV-1{increment}Vpr-infected cultures. Supernatants from HIV-1{increment}Vpr-infected MDMs containing lower concentrations of IL-1β, IL-8 and TNF-α as well as viral proteins showed a reduced neurotoxicity compared to HIV-1wt-infected MDM supernatants. Reduction of neuronal death in the presence of anti-IL-1β and anti-IL-8 antibodies only in HIV-1wt-infected culture implies that the effect of Vpr on neuronal death is in part mediated through released proinflammatory factors.Conclusion: Collectively, these results demonstrate the ability of HIV-1{increment}Vpr to restrict neuronal apoptosis through dysregulation of multiple proinflammatory cytokines in the infected target cells either directly or indirectly by suppressing viral replication. © 2012 Guha et al.; licensee BioMed Central Ltd
Obesity: systemic and pulmonary complications, biochemical abnormalities, and impairment of lung function
A better understanding of the reaction pathways in the formation of Cu2ZnSn(Sx,Se1−x)4 thin films
- …