Time resolved investigation of Cu In,Ga Se2 growth and Ga gradient formation during fast selenization of metallic precursors

Ga segregation at the backside of Cu In,Ga Se2 solar cell absorbers is a commonly observed phenomenon for a large variety of sequential fabrication processes. Here, we investigate the correlation between Se incorporation, phase formation and Ga segregation during fast selenisation of Cu In Ga precursor films in elemental selenium vapour. Se incorporation and phase formation are analysed by real time synchrotron based X ray diffraction and fluorescence analysis. Correlations between phase formation and depth distributions are gained by interrupting the process at several points and by subsequent ex situ cross sectional electron microscopy and Raman spectroscopy. The presented results reveal that the main share of Se incorporation takes place within a few seconds during formation of In Se at the top part of the film, accompanied by outdiffusion of In out of a ternary Cu In Ga phase. Surprisingly, CuInSe2 starts to form at the surface on top of the In Se layer, leading to an intermediate double graded Cu depth distribution. The remaining Ga rich metal phase at the back is finally selenised by indiffusion of Se. On the basis of a proposed growth model, we discuss possible strategies and limitations for the avoidance of Ga segregation during fast selenisation of metallic precursors. Solar cells made from samples selenised with a total annealing time of 6.5 amp; 8201;min reached conversion efficiencies of up to 14.2 total area, without anti reflective coating . The evolution of the Cu In,Ga Se2 diffraction signals reveals that the minimum process time for high quality Cu In,Ga Se2 absorbers is limited by cation ordering rather than Se incorporatio

Investing in Insider-Dominated Firms; A Study of Russian Voucher Privatization Funds

Enterprises; privatization, investments

What is Socialism Today? Conceptions of a Cooperative Economy

Socialism is back on the political agenda in the United States. Politicians and some economists who identify as socialists, however, do not discuss property relations, a topic that was central in the intellectual history of socialism, but rather limit themselves to advocacy of economic reforms, funded through taxation, that would tilt the income distribution in favor of the disadvantaged in society. In the absence of a more precise discussion of property relations, the presumption must be that ownership of firms would remain private or corporate with privately owned shares. This formula is identified with the Nordic and other western European social democracies. In this article, I propose several variants of socialism, which are characterized by different kinds of property relation in the ownership of society’s firms. In addition to varying property relations, I include as part of socialism a conception of what it means for a socialist society to possess a cooperative ethos, in place of the individualistic ethos of capitalist society. Differences in ethea are modeled as differences in the manner in which economic agents optimize. With an individualistic ethos, economic agents optimize in the manner of John Nash, while under a cooperative ethos, many optimize in the manner of Immanuel Kant. It is shown that Kantian optimization can decentralize resource allocation in ways that neatly separate issues of income distribution from those of efficiency. In particular, remuneration of labor and capital contributions to production need no longer be linked to marginal-product pricing of these factors, as is the key to efficiency with capitalist property relations. I present simulations of socialist income distributions, and offer some tentative conclusions concerning how we should conceive of socialism today

Legal determinants of external finance revisited : the inverse relationship between investor protection and societal well-being

This paper investigates relationships between corporate governance traditions and quality of life as measured by a number of widely reported indicators. It provides an empirical analysis of indicators of societal health in developed economies using a classification based on legal traditions. Arguably the most widely cited work in the corporate governance literature has been the collection of papers by La Porta et al. which has shown, inter alia, statistically significant relationships between legal traditions and various proxies for investor protection. We show statistically significant relationships between legal traditions and various proxies for societal health. Our comparative evidence suggests that the interests of investors may not be congruent with the interests of wider society, and that the criteria for judging the effectiveness of approaches to corporate governance should not be restricted to financial metrics

A new approach for alkali incorporation in Cu2ZnSnS4 solar cells

The addition of alkali elements has become mandatory for boosting solar cell performance in chalcogenide thin films based on kesterites (Cu2ZnSnS4, CZTS). A novel doping process is presented here, that consists in the incorporation of sodium or lithium during the deposition of the CdS buffer layer, followed by a post-deposition annealing (PDA). As the doping route leads to more efficient devices in comparison with the undoped reference sample, the influence of PDA temperature was also investigated. Compositional profiling techniques, time-of-flight secondary ion mass spectrometry (TOF-SIMS) and glow discharge optical mission spectroscopy (GDOES), revealed a dependence of the alkaline distribution in kesterites with the PDA temperature. Although the doping process is effective in that it increases the alkaline concentration compared to the undoped sample, the compositional profiles indicate that a significant proportion of Li and Na remains ‘trapped’ within the CdS layer. In the 200 °C-300 °C range the alkali profiles registered the higher concentration inside the kesterite. Despite this, an additional alkali accumulation close to the molybdenum/fluorine doped tin oxide substrate was found for all the samples, which is frequently related to alkali segregation at interfaces. The addition of both, lithium and sodium, improves the photovoltaic response compared to the undoped reference device. This is mainly explained by a substantial improvement in the open-circuit potential (V oc) of the cells, with best devices achieving efficiencies of 4.5% and 3% for lithium and sodium, respectively. Scanning-electron microscopy images depicted a ‘bilayer structure’ with larger grains at the top and small grains at the bottom in all samples. Moreover, the calculated bandgap energies of the CZTS films account for changes in the crystallographic order-disorder of the kesterites, more related to the PDA treatment rather than alkali incorporation. Even if further optimization of the absorber synthesis and doping process will be required, this investigation allowed the evaluation of a novel strategy for alkali incorporation in kesterite based solar cells.Fil: Valdes, Matias Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Hernandez, A.. Catalonia Institute For Energy Research Irec; EspañaFil: Sánchez, Y.. Catalonia Institute For Energy Research Irec; EspañaFil: Fonoll, R.. Catalonia Institute For Energy Research Irec; EspañaFil: Placidi, M.. Universidad Politécnica de Catalunya; España. Catalonia Institute For Energy Research Irec; EspañaFil: Izquierdo, V.. Catalonia Institute For Energy Research Irec; EspañaFil: Cabas Vidani, A.. Swiss Federal Laboratories for Materials Science and Technology; SuizaFil: Valentini, M.. Enea Centro Ricerche Casaccia; ItaliaFil: Mittiga, A.. Enea Centro Ricerche Casaccia; ItaliaFil: Pistor, P.. Universidad Pablo de Olavide; EspañaFil: Malerba, C.. Enea Centro Ricerche Casaccia; ItaliaFil: Saucedo, E.. Universidad Politécnica de Catalunya; Españ

AMBRA1 is able to induce mitophagy via LC3 binding, regardless of PARKIN and p62/SQSTM1

Damaged mitochondria are eliminated by mitophagy, a selective form of autophagy whose dysfunction associates with neurodegenerative diseases. PINK1, PARKIN and p62/SQTMS1 have been shown to regulate mitophagy, leaving hitherto ill-defined the contribution by key players in 'general' autophagy. In basal conditions, a pool of AMBRA1 - an upstream autophagy regulator and a PARKIN interactor - is present at the mitochondria, where its pro-autophagic activity is inhibited by Bcl-2. Here we show that, upon mitophagy induction, AMBRA1 binds the autophagosome adapter LC3 through a LIR (LC3 interacting region) motif, this interaction being crucial for regulating both canonical PARKIN-dependent and -independent mitochondrial clearance. Moreover, forcing AMBRA1 localization to the outer mitochondrial membrane unleashes a massive PARKIN- and p62-independent but LC3-dependent mitophagy. These results highlight a novel role for AMBRA1 as a powerful mitophagy regulator, through both canonical or noncanonical pathways

Ascertaining the notion of board accountability in Chinese listed companies

Accountability is a concept that has been frequently referred to in Anglo-American systems and in the OECD’s corporate governance documents, as well as in the English translations of corporate governance documents from non-English speaking jurisdictions. It is in the Anglo-American literature, in particular, where the word finds prominence. It has been suggested in China that accountability is one of the basic principles of corporate governance that needs to be consistently enforced. But does this mean that board accountability, as it has been provided for in the Anglo-American system, is actually an element of Chinese corporate governance? If not, should it be adopted? Or should China develop a concept that is more appropriately included as a critical part of its own particular corporate governance needs? The paper aims to address these matters in order to ascertain where Chinese corporate governance stands on accountability as far as the boards of large listed companies are concerned, and what it should do. We opine that while there are elements of accountability in Chinese corporate governance, it does not have the form of accountability embraced in Anglo-American systems. But, it is argued, as China moves from having a system totally based on administrative governance to one that is based more on economic governance the kind of approach that applies in Anglo-American jurisdictions is likely to become more relevant. Within a hybrid corporate governance system combining elements of both administrative and economic governance, we develop a unique “wenze system” with forms and characters of accountability that is likely to develop to address the needs of corporate governance in China and the fostering of its listed companies