Muoniated radical states in the organic semiconductor phthalocyanine

Phthalocyanine samples of ZnPc, H2Pc and CuPc were investigated by the muon spin rotation amp; 956;SR technique. In ZnPc and H2Pc, three muoniated radical states of paramagnetic origin were identified, two of which having hyperfine interactions in the range 110 150 MHz and correspondign to muonium addition at the outer benzene rings. The third state presents a smaller hyperfine interaction about 25 MHz , and is tentatively assigned to addition at bridging nitrogen atoms. CuPc has an unpaired electron from the Cu atom, which originates a diamagnetic like signal upon muonium addition. The signal exhibits two components with very different relaxation rates, corresponding to two different spatial couplings of the Cu electron with the muonium s electro

Reply to Comment on Role of the transition state in muon implantation and Thermal spike in muon implantation

The transition state model proposed for muonium formation in solids is critically discussed with respect to the delayed capture model. The two models differ mainly in how the electron capture at the muon is treated. In the delayed capture model the electron stems from the ionization track of the implanted muon. Important electron mobility information is derived in several papers from the time the electron needs to arrive at the muon. In our transition state model, the electron is picked up in the charge exchange regime during slowing down and is present already when the muon stops in the target. Thus, no information about electron mobility can be obtained from such measurement

Células solares ultrafinas de Cu (In,Ga)Se2 : passivação de interfaces

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMO: A comunidade de Cu(In,Ga)Se2 (CIGS) tem focado grande parte da sua investigação no estudo e melhoramento das propriedades cristalinas do CIGS.A última estratégia utilizada, que tem permitido aumentar o valor de eficiência das células solares, passa pela implementação de elementos alcalinos através de tratamentos pós-deposição (PDT). Para se atingir valores de conversão de eficiência competitivos é necessário melhorar as interfaces do CIGS. Neste estudo, focamo-nos no estudo das propriedades morfológicas, estruturais e optoelectrónicas entre o CIGS e a alumina (Al2O3), que tem o potencial de ser usada como camada passivadora frontal. Pode-se concluir que as propriedades morfológicas e estruturais não são alteradas devido à deposição do Al2O3. O Al2O3 não resiste ao banho químico usado para a deposição do CdS. O Al2O3 apresenta um valor de densidade de defeitos baixos, uma propriedade desejada destas camadas. Este estudo demonstra a potencialidade de se utilizar a Al2O3, para camadas buffer alternativas, que não usem processos químicos durante a sua deposição.ABSTRACT: Cu(In,Ga)Se2 (CIGS) community have been focusing the research line in the study and improvement of the crystalline properties of CIGS. The last trend, to increase the light to power conversion efficiency values, is the use of fluoride-alkaline post-deposition treatments. (PDT). To reach competitive efficiency values, it is necessary to focus on the improvement of CIGS interface. In this work, we focus on the study of the structural, morphological and optoelectronic properties in the interface of CIGS and alumina (Al2O3) which has the potential to be used as front passivation layer. We can conclude that the structural and morphological properties of CIGS remain the same with the deposition of Al2O3. When it was deposited the CdS, on Al2O3, the Al2O3 layer does not resist to the CdS chemical bath deposition. The interface Al2O3/CIGS has a low density of defects value, which is one of the desired properties of a passivation layer. This study demonstrates the potential of using Al2O3 as a front passivation layer with alternative buffer layers to CdS that do not use chemical processes during the deposition.info:eu-repo/semantics/publishedVersio

Inflationary potentials yielding constant scalar perturbation spectral indices

We explore the types of slow-roll inflationary potentials that result in scalar perturbations with a constant spectral index, i.e., perturbations that may be described by a single power-law spectrum over all observable scales. We devote particular attention to the type of potentials that result in the Harrison--Zel'dovich spectrum.Comment: 8 pages, 3 figures. New general derivation method, structure change

Muoniated radicals in the organic semiconductor zinc-phthalocyanine

[mu]SR experiments were conducted on the organic semiconductor zinc-phthalocyanine (Zn-Pc) in order to identify and characterize the muon states in this material. Transverse-field experiments at 0.5 mT reveal the existence of paramagnetic muon states in Zn-Pc, with the formation probability of nearly 100%. Two different muoniated radicals were detected, with hyperfine parameters of 127 and 142 MHz; muonium is thus bound to the Zn-Pc molecule at two different sites. Preliminary longitudinal field measurements indicate the onset of spin dynamics above 200 K. The observed relaxation is interpreted as due to spin exchange scattering with charge carriers.http://www.sciencedirect.com/science/article/B6TVH-47GJ103-3/1/9b94809bb0c63bc7bcd20fdfc0073d3

Structural analysis and 57Fe Mössbauer spectrometry of Zr6FeSn2 and related compounds

Hexagonal compounds of formula Zr6FeX2 were prepared and studied by X-ray and neutron diffraction and by 57Fe Mössbauer spectroscopy. The first results indicate that most of the compounds can be prepared mainly as a single phase after at least 5 weeks of annealing at a temperature close to 900 °C. In particular, the hyperfine parameter distributions in Mössbauer spectra reflect the ability to form pure phases.http://www.sciencedirect.com/science/article/B6TWY-4KXDWF9-4/1/9d2fe798d72e4ef53fbe83343d6a156

Spin exchange of muonium in CdS

http://www.sciencedirect.com/science/article/B6TVH-4V34D8T-7/2/3a955c2f8a5ab1c3fde448c9a148307

Catches of Pelagic Sharks by Subsurface Longline Fisheries in the South Atlantic Ocean during the Last Century: A Review of Available Data with Emphasis on Uruguay and Brazil

Pelagic sharks are typically discarded as bycatch in subsurface longline fisheries in the South Atlantic Ocean. During the last 40 years of the 20th century, despite considerable fishing effort involving subsurface longline fleets from more than seven countries, there were few available data describing catch rates and relative abundances and distributions of the species caught. The majority of information came from small-scale longline fleets operating out of Brazil and Uruguay, where sharks historically have been landed and sold in local markets. This review shows that most of the large-scale temporal fluctuations in catch per unit of effort (numbers or weights of fish caught per 1,000 hooks per year) in these small-scale fisheries can be attributed to market-oriented factors (reflecting variabilities in consumer demand for various species) and the discovery of new fishing grounds. Toward the end of the century, gear-related changes also appear to have had an impact on catch rates. The lack of data precludes analyses of smaller-scale temporal and spatial trends in catches and relative abundances for nearly all species, except the blue shark (Prionace glauca). The available data indicate that such trends in the southwestern Atlantic Ocean can be largely attributed to movements associated with reproduction. We propose that the future effective management of pelagic sharks in the South Atlantic would be facilitated by implementation of more rigorous methods of obtaining information on catches and biological parameters for the key species, as well as an examination of the factors influencing gear selectivity

Low-energy muon [LEM] study of Zn-phthalocyanine and ZnO thin films

http://www.sciencedirect.com/science/article/B6TVH-4V2NP2J-14/2/e2844eb805cd79148fe2c51116014ae